Home to a culturally heterogeneous population, India is also a melting pot of genetic diversity. The population architecture characterized by multiple endogamous groups with specific marriage patterns, including the widely prevalent practice of consanguinity, not only makes the Indian population distinct from rest of the world but also provides a unique advantage and niche to understand genetic diseases. Centuries of genetic isolation of population groups have amplified the founder effects, contributing to high prevalence of recessive alleles, which translates into genetic diseases, including rare genetic diseases in India.Rare genetic diseases are becoming a public health concern in India because a large population size of close to a billion people would essentially translate to a huge disease burden for even the rarest of the rare diseases. Genomics-based approaches have been demonstrated to accelerate the diagnosis of rare genetic diseases and reduce the socio-economic burden. The Genomics for Understanding Rare Diseases: India Alliance Network (GUaRDIAN) stands for providing genomic solutions for rare diseases in India. The consortium aims to establish a unique collaborative framework in health care planning, implementation, and delivery in the specific area of rare genetic diseases. It is a nation-wide collaborative research initiative catering to rare diseases across multiple cohorts, with over 240 clinician/scientist collaborators across 70 major medical/research centers. Within the GUaRDIAN framework, clinicians refer rare disease patients, generate whole genome or exome datasets followed by computational analysis of the data for identifying the causal pathogenic variations. The outcomes of GUaRDIAN are being translated as community services through a suitable platform providing low-cost diagnostic assays in India. In addition to GUaRDIAN, several genomic investigations for diseased and healthy population are being undertaken in the country to solve the rare disease dilemma.In summary, rare diseases contribute to a significant disease burden in India. Genomics-based solutions can enable accelerated diagnosis and management of rare diseases. We discuss how a collaborative research initiative such as GUaRDIAN can provide a nation-wide framework to cater to the rare disease community of India. India is the sixth largest country in the world in terms of its geographical area and the second largest country in population density. The people of the country are diverse in terms of their social, linguistic, cultural, and racial backgrounds. Evolutionarily, the Indian subcontinent has been a corridor for different migratory waves arising from Africa, through land as well as coastline routes , 2. GeneThe genetic diversity is well reflected in the mitochondrial DNA (mtDNA), Y chromosomes, and candidate genes/markers, which have provided a fair understanding of the relatedness and divergence of specific communities or tribes of India , 11–17. A national genome-wide approach to understand the population architecture and look for markers specific to the Indian subcontinent was undertaken by the Indian Genome Variation (IGV) consortium, which used single-nucleotide polymorphisms (SNPs) to type 900 genes from over 1800 individuals across 55 endogamous populations. High heterozygosity values, varying allele frequencies, and common polymorphic haplotypes of sub-populations were shown to underline the heterogeneity within the Indian population. Additionally, unique mutations were discovered within the subcontinent, with concomitant founder effects , 21, 22.Plasmodium falciparum [The findings of the IGV consortium have led to the identification of specific markers and better understanding of genotype-phenotype correlations in Indian sub-populations. The phenotypically distinct outcomes of sub-population specific genotypes could be shown in susceptibility or resistance towards lciparum –27, risklciparum , homocyslciparum , and rislciparum , 31, amolciparum –35. Sub-lciparum –38.Thus, the extensive genetic heterogeneity and the endogamous cultural practices clearly suggest that there is a need to demarcate genetic affinities and distinctions among sub-populations. These findings also underscore the genetic distinction of the Indian population from the populations of other countries, warning against the imputation of genetic information from other populations. Evidently, a generalization of the population architecture can lead to erroneous interpretations in clinical settings.India, being a melting pot of genetic diversity, is also home to strict inbreeding practices and founder effects, which have resulted in the accumulation of deleterious genetic variations . The repWhat is striking, apart from the high prevalence of monogenic diseases, is the heterogeneity in the outcome of the same disease. The clinical heterogeneity in blood disorders in India has been attributed to subpopulation-specific variations and allele frequencies –57. SimiA number of genome-scale datasets of Indians have surfaced in recent years. These include an initiative by the IGV consortium of six laboratories affiliated to the Council of Scientific and Industrial Research (CSIR) with other key players, that typed SNPs and known markers scattered among 1000 genes , 22, 65.It is to be noted that given the heterogeneity shown by IGV and other studies, the number of Indian genomes and exomes that are available till date under-represents the peninsula’s diversity. This gap in the availability of baseline genetic information can hence act as a barrier in understanding the causes of diseases that are prevalent in the country and calls for a nation-wide genome project, as being undertaken in other parts of the world .Rare diseases or orphan diseases are defined as those which afflict a minimal fraction of a population. An attempt to identify the parameters that can be used to define a rare disease was made by the ‘Rare Disease Terminology & Definitions Used in Outcomes Research Working Group.’ The study concluded that a disease with the average global prevalence of 40–50 cases per 100,000 people can be called as a rare disease . The OrpThe pervasive endogamy and founder effects in sub-populations have led to a high prevalence of autosomal recessive rare genetic diseases in India, compared to other parts of the world. While there is no appropriate standard definition to describe a rare disease in India, Indian Council of Medical Research (ICMR) has defined a disease as rare if it affects less than 1 person in 2500 individuals . The OrgThe estimation of the prevalence of rare genetic diseases across India is limited by the lack of a centralized clinical registry of patients with rare genetic diseases. However, extrapolating the numbers in the Indian scenario, the Foundation for Research on Rare Diseases and Disorders has estimated that about 70 million people are affected by rare diseases . Rare diGiven the estimate of approximately 70 million people living with rare diseases, most of them undiagnosed, rare disease management contributes a huge burden for a developing country like India. The accurate socio-economic burden due to rare genetic diseases in India is unknown. Incidentally, the social impacts of hemophilia have been recorded adequately, in spite of an underestimated prevalence due to lower case reporting . Other sDespite over 70 million individuals being affected by rare diseases, India has limited resources committed to treating or understanding rare diseases. In recent years, Indian Council of Medical Research (ICMR) has taken a step towards bridging the gap between patients suffering from rare genetic diseases and healthcare providers by launching The Indian Rare Disease Registry. The registry acts as a common repository for data concerning rare disease patients throughout the country . FurtherMolecular Diagnostics, Counselling, Care and Research Centre (MDCRC) is a not-for-profit charitable organization which takes a holistic approach to manage Duchenne Muscular Dystrophy (DMD) patients, mostly catering to individuals from the southern part of India (Tamil Nadu). MDCRC undertakes genetic counseling in addition to providing screening for DMD and Spinal Muscular Atrophy (SMA). A pilot study by MDCRC estimated the prevalence of DMD to be 2.4 times higher as compared to global estimates . The UttSanofi-Genzyme’s India Charitable Access Program (INCAP), Shire HGT's charitable access program in partnership with Direct Relief , and Protalix Biotherapeutics have provided access to enzyme replacement therapy for lysosomal storage diseases in India . Apart fThe Genomics for Understanding Rare Diseases: India Alliance Network (GUaRDIAN) at CSIR-Institute of Genomics and Integrative Biology (CSIR-IGIB), Delhi is a unique research initiative in India that uses the power of genomics to solve and understand rare diseases. Details about the GUaRDIAN program are elaborated in the next section. Apart from those listed above, several government research laboratories, hospitals, and not-for-profit organizations also provide specialized tests for a specific patient group or community . Genomics for Understanding Rare Diseases: India Alliance Network (GUaRDIAN) is a research consortium which was proposed to address the above challenges. The consortium includes clinicians, clinical geneticists, genomics scientists, computational analysts, and basic research biologists, among others. The clinicians and clinical geneticists form the primary contacts and act as caregivers for the patients. The geneticists, genomics scientists, and researchers provide the necessary expertise required to identify the genetic variations, create models for understanding disease mechanisms, and explore the therapeutic potential of small molecules for rare genetic diseases. The simplified workflow of the GUaRDIAN consortium is summarized in Fig. The aim of the GUaRDIAN consortium is to establish a unique collaborative framework in health care planning, implementation, and delivery in the specific area of rare genetic diseases. The consortium proposes to apply the power of genomics for systematic characterization and diagnosis of rare genetic diseases in India. The GUaRDIAN network is connected to hospitals and major tertiary care centers across India. The consortium currently encompasses over 240 clinicians/researchers, from 70 clinical/research centers across India . The GUaA strong foundation of an ethical and legal framework is necessary for seamless collaboration and sharing of genetic data across the boundaries of institutions. The GUaRDIAN consortium is strongly anchored on the basic principles of beneficence, reciprocity, justice, and professional responsibility. As part of the collaborators’ network, a common format for collection of clinical and genetic data has been created. Additional efforts have gone into standardizing the patient information. The benefits and potential ethical, legal, and social implications of whole exome or genome sequencing and availability of the anonymized data in the public domain are conveyed in detail to the patients and family. The identity stripped clinically annotated data of variations is available to all the members through a firewalled access. In addition, publications in peer-reviewed journals serve as the major interaction points for sharing findings with the general clinical and research community.As part of the collaborative initiative, a referral system for systematic collection and curation of baseline data is being maintained. The program collects detailed clinical information, including the signs, symptoms, and clinical investigations performed on the patient and family members. The GUaRDIAN maintains a semantically oriented framework, which relies extensively on the internationally accepted and popularly used semantic ontologies established and widely used including the human phenotype ontology . The appA centralized sequencing facility has been established at the CSIR-Institute of Genomics and Integrative Biology (CSIR-IGIB), Delhi, which can be accessed by any collaborator in order to generate high-quality NGS sequencing data as per international standards –136, witGUaRDIAN stands for providing scientifically sound and clinically actionable solutions. The genomes/exomes of patients are analyzed through custom built in-house bioinformatic pipelines to identify the most accurate genetic variation that can explain a certain condition. Further, the pathogenicity of variants is predicted by the latest guidelines laid down by the American College of Medical Genetics and Genomics . The GUaData sharing also forms a major component of the program and collaboration. The anonymized clinically annotated data of variations is available to all members through a firewalled access. In addition, the summary data of each novel variant and/or allele frequencies would be available in the public domain without access restrictions. Credits for contributions are a major point to address in such a scalable collaborative network. All collaborating members of the network shall agree to adhere to basic principles of data veracity and ethical codes of conduct. The credit-sharing agreement forms the major framework of trust between participating members. This shall be in line with principles laid out for biomedical resource contributions .Once the GUaRDIAN computational analysis identifies a pathogenic variation of clinical significance, it is subjected to validation by segregation analysis. After this, if the identified genetic variation is immediately actionable, the information is transferred to the clinician as a research report which will be used for patient counseling. This genetic information can further be used for making informed decisions by the family. Wherever required, the genetic variation information is utilized for potential community-level screening programs, thus building towards affordable diagnostic solutions.In the case where novel pathogenic variations are identified, researchers at the GUaRDIAN consortium replicate the disease in suitable models such as zebrafish and patient-derived IPSCs to gain the correlation between the disease phenotype and the identified variant. Genetic engineering to create disease models also provides the opportunity for discovery of novel therapeutics as well as to repurpose existing drugs for new indications in rare genetic diseases.A large number of cases have been solved through the GUaRDIAN program, and a subset of interesting investigations have been published in peer-reviewed journals, which encompass diseases as diverse as epidermolysis bullosa –143, fam megalencephalic leukoencephalopathy with subcortical cysts 1 (MLC1) gene in leukodystrophy was instrumental in community service in the form of affordable diagnostics. Six children from a consanguineous Muslim family belonging to the Nalband community from north India were presented with difficulty in balancing the head and inability to sit independently, with recurrent episodes of seizures. Based on the clinical characteristics, the provisional diagnosis of leukodystrophy was made; however, leukodystrophies are a class of disorders with the involvement of multiple genes. Whole exome sequencing revealed a homozygous variation in the MLC1 gene, found to be segregated among all the affected members and was absent in all the unaffected members. Based on this, the diagnosis of megalencephalic leukoencephalopathy with subcortical cysts (MLC) was confirmed. MLC is a rare leukodystrophy characterized by macrocephaly, progressive motor dysfunction, recurrent episodes of seizures, and mental retardation. Further, three more families from the same community were found to be affected and carried the same variation, indicating a founder effect. As a follow up for this, an additional 83 members of the community were screened. Out of these, 24 were found to be the carriers and 9 were affected [MLC1 has been developed for carrier status determination and prenatal screening, at an affordable cost.Of the many success stories of GUaRDIAN, the diagnosis of a rare mutation inaffected . The NalKeratin 5 (KRT5) gene in a large multigenerational family from northwestern India. The variant was shown to be segregated in nine affected members in the family but found absent in five unaffected members. The study reported the first causative mutation for EBS from India [Keratin 14 (KRT14) gene in an autosomal recessive form of EB, in two siblings presented with generalized blistering of the skin and dystrophic nails. The same study identified a known homozygous stop gain variant in the same gene in a child with trauma-induced blistering all over the body [laminin subunit alpha 3 (LAMA3), laminin subunit β3 (LAMB3), collagen type XVII α1 (COL17A1) [COL7A1 gene [Another area where the GUaRDIAN has made a significant contribution is in the rare diseases of the skin. Epidermolysis bullosa (EB), a skin-blistering disease, was once considered ultra-rare in the Indian population. Epidermolysis bullosa simplex (EBS) is the most common subtype of EB. The GUaRDIAN team identified a novel variant in the om India . Whole ethe body . In caseCOL17A1) . In the 7A1 gene . There h7A1 gene , 154.dihydropyrimidine dehydrogenase (DPYD) gene, which determines the metabolism of the commonly used anti-neoplastic drug 5-fluorouracil, in south-east Asian countries [GUaRDIAN has contributed to the identification of the pharmacogenetic variants in ountries . The conountries  and Qataountries , 158, anountries , 160. GUountries .In the era of clinical genomics, it is imperative for clinicians to be well equipped with the basics of high-throughput data analysis so as to interpret the data concerning a certain disease. Keeping this in mind, the GUaRDIAN consortium initiated an outreach program, where clinicians are trained in basics of NGS technologies and systematic computational analysis of sequencing data as a part of continuing medical education (CME) workshops. A handbook called ‘Exome Sequence Analysis and Interpretation for Clinicians’ has been prepared and made available for free download from Google Books . Over 80It has been increasingly shown that the challenges of genetic and phenotypic heterogeneity which makes diagnosis of rare genetic diseases cumbersome could potentially be addressed by using next generation sequencing techniques, enabling the high-throughput identification and annotation of causal variants , 163. InIn the case of Duchenne muscular dystrophy (DMD), a wide spectrum of mutations and frequencies have been shown in patients from different Indian sub-populations –166. TheNiemann–Pick disease type C2 (NPC2) gene [Lysosomal storage disorders (LSD), a class of more than 50 genetic diseases, are found to be of high burden in India . The oveC2) gene .An estimated one million Indians are affected by primary immunodeficiencies, a class comprising of hundreds of genetic disorders . The utmMitochondrial disorders are difficult to diagnose owing to overlapping phenotypes and multi-system involvement. Whole mitochondrial genome sequencing coupled with nuclear gene sequencing has been performed to establish genotype-phenotype correlations in a cohort of patients from South India . Whole eIn case of autosomal recessive forms of ataxia, such as spastic ataxia  and cereMLC1 gene in individuals from Nalband community suffering from megalencephalic leukoencephalopathy with subcortical cysts (MLC) [ DPYD gene that were found to be associated with 5-FU toxicity in South Asian population [Although the cost of next generation sequencing-based diagnostics is declining, with more than 70 million people suffering from a genetic disease in India, affordable and faster measures are required to cater to the needs of the ailing population. CSIR-IGIB has an ongoing outreach platform to provide affordable access to genetic testing for common genetic diseases. The program named “Genomics and other Omics tools for Enabling Medical Decision (GOMED)”  providests (MLC) . As partpulation  has beenAs a step towards improving public health, efforts have also been undertaken to compile a directory of genetic test services and counseling centers in India. The directory includes about 120 centers across various states in India. It acts as a resource for clinicians as well as researchers for referring to facilities which provide accessible and comprehensive public healthcare .There are a few priority areas that are emerging in the country as far as rare diseases are concerned. Newborn screening at a nation-wide level is pivotal in reducing the burden of rare diseases. In 2014, India Newborn Action Plan (INAP) was released to reduce the incidence of child birth defects and stillbirths . While aFor a large and heterogeneous population like that of India, it has been shown that the international genomics initiatives such as the 1000 genome project have an inadequate representation of the genetic diversity due to limited sampling . In highIndia is home to culturally and genetically diverse populations, which are burdened by genetic diseases. Due to the high prevalence of recessive alleles owing to endogamous practices, rare diseases form a significant burden in India. Genomics can greatly aid in addressing rare disease burden by faster and more accurate diagnoses. The Genomics for Understanding Rare Diseases: India Alliance Network (GUaRDIAN) provides a template for a nation-wide collaborative platform that uses the power of genomics to dissect the rare disease conundrum. More such pan-India genomics-driven initiatives can help in deriving Indian-specific references for deducing pathogenic and benign variations in the population, which can pave the way for precision medicine, including in the rare disease space.


The purpose of this pictorial review is to present an overview of the radioclinical features of osteomyelitis.The presentation of the disease may vary depending on the clinical stage , the pathogenesis of the infection and the age of the patient. Thorough knowledge of the basic pathophysiological mechanisms is a prerequisite to understanding the variable imaging appearance of osteomyelitis.Special subtypes of osteomyelitis including CRMO and SAPHO will be discussed very shortly. Osteomyelitis (OM) is defined as an infection of the bone marrow and adjacent osseous structures with potential surrounding soft tissue extent. OM has a variable imaging appearance and therefore often mimics other bone diseases . The purGenerally one may distinguish three clinical stages , although in clinical practice there may be some overlap between these stages.The routes of contaminations may vary in those clinical stages. In children hematogenous spread is the predominant route of infection, whereas in adults spread from a contiguous source, direct contamination or post-operative infection is much more frequent.Furthermore, clinical manifestations may also differ according to the age of the patients. Particularly in infants the clinical findings are often more pronounced including local swelling, pain, reduced movement or refusal to move the affected limb, particularly in the acute phase. On the contrary, in adults the clinical onset is often more insidious. In children the tubular bones such as tibia and femur are the most common sites of infection, whereas the axial skeleton is most frequently affected in adults.Laboratory findings typically show an increase of c-reactive protein (CRP) and erythrocyte sedimentation rate (ESR) especially in acute osteomyelitis in children whilst the white blood count may be normal. The evolution of the CRP levels correlate with the response to the therapy. Cultures are essential for accurate treatment but in acute setting only half of the blood cultures are positive impeding the diagnosis 34.3There are different routes of contamination of which hematogenous spread of a micro-organism is the most frequent. In 95 percent of the cases the micro-organism is Staphylococcus aureus, but a variety of micro-organisms may be responsible.  Other poThe nature of blood supply to the diaphysis, metaphysis and epiphysis depends on the age of the patient. Thorough knowledge of these different patterns allows an understanding of the different radiological patterns of OM between children and adults Figure  5]..5].Although traditionally the growth plate has been considered a barrier for epiphyseal extension of the infectious focus in children because of the specific age-dependent vascularization Figures , this baIn rare scenarios, the infection spreads predominantly by the circulus articuli vasculosus of Hunter supplying the epiphysis Figure . This maImaging findings Figures , 12, 13 acute OM are summarized in Figures Consecutive changes occurring in Plain radiography is not sensitive for the assessment of the osseous extent of the lesion in the first ten days after onset of infection. Nonspecific soft tissue swelling may be seen. Bony changes such as periosteal thickening, loss of trabecular architecture, osteopenia and osteolytic destruction are seen after one week at the earliest. However, plain radiography is useful as a baseline study for further follow-up and for differential diagnosis purposes.Ultrasound (US) allows easy comparison of both sides. It is an accurate and quick tool to detect subperiosteal spread in acute OM particularly in children because of loose attachment of the periosteum. Visualization of periosteal elevation, fluid collections or abscesses are signs suggestive of osteomyelitis. A soft tissue abscess presents as a hypo-echogenic collection to normal muscle with a peripheral vascularized rim of increased Power Doppler signal. US detects these signs earlier than standard radiography and allows US-guided biopsy and/or aspiration Figure  7]..7].Magnetic Resonance Imaging is the modality of choice for early detection of acute OM. Bone marrow changes are detected within three to five days after disease onset on Fat–Sat T2-weighted imaging (WI). OM can spread to the joint depending on the position of the joint capsule compared to the growth plate. An extra-articular location of the growth plate does not predispose to joint infection, whereas intra-articular position of the growth plate may cause rapid spread to the adjacent joint Figure . Soft ti89Subacute osteomyelitis is characterized by the presence of Brodie’s abscess at the metaphysis. It typically presents as an oval radiolucent lesion with peripheral sclerosis within the metaphysis of the long bones on plain radiography Figure . The sha11Inhomogeneous osteosclerosis and/or sequestrum formation (necrotic bone) is characteristic for chronic osteomyelitis on plain radiography. A sequestrum represents a segment of necrotic bone that is separated from the living bone by granulation tissue and bone resorption. It is typically denser than the living bone . In someBone scintigraphy is able to detect osteomyelitis with high sensitivity. In the delayed phase an increased activity in the affected bone is seen, uptake in the surrounding bone and/or soft tissue may be present as well. The specificity is, however, low. Multiplicity is easily detected by this method .Computed Tomography (CT) is useful in evaluating chronic osteomyelitis in areas with a complex anatomy. CT may provide information regarding the presence of sequestra, cloaca, cortical destruction and the thickness of the involucrum. Particularly in the assessment of sequestrum formation, CT is more accurate than plain radiography and MRI. In addition, it is a useful technique for imaging-guided needle biopsy and aspiration material for microbiology . HoweverGarré’s sclerosing osteomyelitis is a specific subtype typically affecting the mandible but can also be seen in the long bones. Children and young adults are mainly affected. The etiology remains unclear, as the cultures are generally negative an underlying viral infection is suspected . PatientCRMO is defined as an auto-immune disease with recurrent inflammatory lesions of the bone that typically affects children . It typiThe combination of synovitis, acne, pustulosis, hyperostosis and osteitis is designated as SAPHO and is seen as the adult counterpart of CRMO. It represents an inflammatory disorder of unknown etiology in which osteitis is a key symptom. The axial skeleton is preferentially affected with predominant involvement of the sternoclavicular joints  Figure  and the Plain radiography in CRMO initially shows osteolytic lesions, sometimes associated with periosteal reaction having a so-called “onion ring” appearance Figure . In lateIn SAPHO, the affected joints show sclerosis and erosions of the joint facets which are all signs of arthritis. Hyperostosis and enthesopathy are visualized .CT is able to detect and assess the extent of these bony changes with precision .MRI shows bone marrow edema in acute CRMO lesions with a hypo-intense SI on T1–WI and hyperintense SI on T2–WI Figure . TransphOf note, according to other authors CRMO and SAPHO belong to the spectrum of spondylarthropathy rather than being an infection. Further discussion of these entities is therefore beyond the scope of this pictorial review.The variable imaging appearance of osteomyelitis may be explained by the different pathogenic mechanisms involved in the spread of the infection and by the age-related vascularization of bone. Standard radiography is still the baseline examination for follow-up and differential diagnosis. Ultrasound is the preferred modality in case of suspicion of acute osteomyelitis in children or concomitant septic arthritis. US-guided biopsies and/or aspiration are safely and easily performed. CT may be useful in the evaluation of chronic osteomyelitis, particularly in areas with a complex anatomy. CT may provide information regarding the presence of sequestra, cloaca, cortical destruction and reactive involucrum formation. In addition, it is used for imaging-guided biopsy and aspiration of infectious material for microbiological examination. MRI is the preferred modality for early detection of osteomyelitis. The fat globule sign on T1–WI is pathognomonic for acute osteomyelitis whilst the penumbra sign is pathognomonic for a Brodie abscess in subacute osteomyelitis. A combination of T1– and Fat–Sat T2–WI and gadolinium enhanced imaging is mandatory.


The World Health Organization (WHO) considers that obesity has reached proportions of pandemic. Experts also insist on the importance of considering obesity as a chronic disease and one of the main contributors to the worldwide burden of other nontransmissible chronic diseases, which have a great impact on health, lifestyle, and economic cost. One of the most current challenges of biomedical science faces is to understand the origin of the chronic nontransmissible diseases, such as obesity and cancer. There is a large evidence, both in epidemiological studies in humans and in animal models, of the association between obesity and an increased risk of cancer incidence. In the last years, the initial discovery of epigenetic mechanisms represents the most relevant finding to explain how the genome interacts with environmental factors and the ripple effects on disease pathogeneses. Since then, all epigenetic process has been investigated by the scientific communities for nearly two decades to determine which components are involved in this process. DNA/RNA methylation and miRNA are classified as two of the most important representative classes of such epigenetic mechanisms and dysregulated activity of such mechanism can certainly contribute to disease pathogenesis and/or progression especially in tumors. This review article serves to highlight the impact of DNA/RNA methylation and miRNA-based epigenetic mechanism activities in the interplay between obesity and the development and clinical significance of colorectal cancer. The World Health Organization (WHO) considers that obesity has reached pandemic proportions: more than 1900 million adults are overweight and, of these over 650 million of them, obesity , 3. One During tumorigenesis, adipocytes that are found near to cancer cells suffer several morphological and biochemical alterations and are implicated in developing of the Cancer-Associated Adipocytes (CAAs) which influence cancer cell malignancy. CAAs located close to the invasive front acquire different fibroblast-like features. Lipids secreted by adipocytes are transferred to cancer cells and used for energy production through beta-oxidation. The loss of expression of differentiation markers in CAAs such as adiponectin or leptin and the increased secretion of proinflammatory cytokines as Interleukin 6 (IL-6) and tumor necrosis factor (TNF) generate a permissive niche for tumor growth and dissemination by stimulating adhesion, migration, and invasion proprieties of malignant cells . MoreoveIn particular, the new location of the CAAs transforms them in highly metabolic cell that secrete greater amounts of cytokines associated with insulin resistance . In any Epigenetic processes, including DNA methylation, modification of histones and noncoding RNAs of different size and function, change genes expression without modifying the DNA sequence. They are sensitive to external , internal (hormones and inflammation markers), and genetic factors and reversible and can be passed on to later generations. Two large-scale epigenetic studies have identified a large number of DNA methylation loci associated with Body Mass Index (BMI) . Clearly FTO (fat-mass and obesity-associated) gene have been consistently associated with obesity. The great success on a large scale of the genome-wide association studies (GWAS) was the discovery that the FTO locus could regulate the expression of several genes despite their distance in the linear sequence of DNA to influence body weight, through the regulation of epigenetic mechanisms related to obesity .–21. FTO 6A), which revealed that it is found in at least 25% of all mRNAs, typically near stop codons [ FTO gene research is the recent discovery of FTO protein as the first m6A RNA demethylase [6A in RNA can act as a new epitranscriptomic marker [6A process has been associated with cancer, contributing to the self-renewal of cancer stem cell, promotion of cancer cell proliferation, and resistance to radiotherapy or chemotherapy, and playing a crucial role in the metabolism of mRNA and regulation of noncoding RNAs in cancer cells [Epigenomics connects genomics with environmental factors in the pathogenesis of several diseases. In fact, another emerging concept in the regulation of gene expression is that some modified nucleotides are found internally in mRNA. These modifications constitute a new concept of epitranscriptomic code. The initial concept of epitranscriptome was introduced with the transcriptomic scale mapping of N6-methyladenosine (mp codons . In factethylase . This fic marker . Recent 5C). This process can take place passively, without methylation of the newly synthesized chain after DNA replication, or actively, by mechanisms that do not depend on replication. Active demethylation of DNA has just begun to be studied, along with the discovery of another methylated variant of cytosine, 5-hydroxymethylcytosine (hm5C), and the enzymes that catalyze its generation from m5C [5C and its impact on gene expression, but the products of DNA demethylation are not known in detail, whether they are only intermediates or epigenetic marks by themselves. Therefore, their study will reveal in a novel way the implication of epigenetics in cancer and obesity processes.Sometimes, it is necessary to go beyond the sequences of the genes to understand better the regulatory mechanisms of their expression, because, often, genomic studies do not identify the causes and etiologies of many diseases. One of the important mechanisms that explain the regulatory elements of the genes is the epigenetic modifications in DNA such as methylation, which consist in the addition of a methyl group to position 5 of the cytosine bases, which generates 5-methylcytosine  overlap, such as CpG hypermethylated islands, which may explain the epigenetic instability that drives the onset of cancer in individuals with obesity . These sEpigenetic gene inactivation in transformed cells involves many “belts of silencing”. One of the best-known lesions of the malignant cell is the transcriptional repression of tumor-suppressor genes by promoter CpG island hypermethylation. Currently, the scientific community are beginning to understand a great deal of epigenetic silencing of tumor-suppressor genes in human cancer by CpG island promoter hypermethylation. In the process of completing the molecular dissection of the entire epigenetic machinery involved in methylation-associated silencing, such as DNA methyltransferases, methyl-CpG binding domain proteins, histone deacetylases, histone methyltransferases, histone demethylases, and specially the identification of many more hypermethylation-silenced miRNA genes with tumor-suppressor function in human cancer, the epigenetic silencing of these miRNAs will become an excellent target . The impThe low vitamin D levels in colorectal cancer and high expression of vitamin D receptor in adipose tissue may, at least in part, mediate this relationship by modifying adipose tissue DNA methylation and promoting inflammation. Although more studies are needed to discover the precise mediators and mechanisms that determine this relationship, the possible mediation of adipose tissue in colorectal cancer should be born in mind to create new treatments and preventive strategies for colorectal cancer , 31.The recent concept of the implication of epigenetic variations in numerous pathologies has directed attention towards the development of new markers for its detection. Therefore, it has become necessary to develop new analytical tests to identify epigenetic changes through molecular biomarkers related to the active or silenced state of the regions in which they are found, in order to detect changes in methylation, both in DNA and in RNA, whose manifestations can be revealed in advance even of the development of the disease. Every cell, including small and early cancerous lesions, leaves a record of its physiological state that is reflected in the fragments of DNA and RNA, proteomic and circulating metabolic products. The molecules in circulation make up a file of biomarkers, which constitute a potential reservoir of diagnostic information for the complete organism, whose clinical use depends on the sensitivity of the detection and quantification methods of methylated DNA/RNA from liquid biopsies , 33. DesThe MicroRNAs (miRNAs) consist of the most clinically important noncoding RNA families and have been investigated by the scientific communities for nearly two decades, since the initial discovery of the RNA interference (RNAi) pathway by Fire and Mello in 1998 . StructuThis regulatory function by miRNAs revealed a further level of complexity in the nature of gene regulation within a vast spectrum of physiological processes and, consequently, highlighted the influence of miRNAs in human disease pathology and progression and/or inhibition, whenever such miRNAs exhibit dysregulated activity . In addiThe first indications of miRNA involvement in the regulation of lipid metabolism date back to 2006, where the study conducted by Esau and colleagues elucidated that miR-122 upregulation led to increased plasma cholesterol levels, together with a decrease in lipid metabolic activities, in murine study models . FurtherThe conclusions of this seminal study were that miR-143 and miR-103 upregulation both lead to exacerbated adipogenesis, with additional evidence provided by the correlated increases in adipogenesis markers and triglyceride production in such murine in vivo models . The firγ coactivator 1 alpha (PPARGC1A), leading to a reduction in lipid oxygenation capacity within muscles [The first reporting of the link between circulating miRNA expression and obesity was by the Wang study in 2013 . The res muscles . FTO expression [ FTO is a direct target gene for miR-33 activity [In 2014, Shao and colleagues revealed the initial connection between miR-33 andpression . This stactivity .In 2015, Chu and colleagues highlighted the influence of miR-181a on lipid regulatory activities . The stuMore recently, the study by O'Neill and colleagues revealed the utility of analyzing the circulating expression level of miR-758-3p as a means for discerning between obesity and metabolic syndrome . FurtherThe study described above, conducted by Kloting and colleagues, could also be deemed to shed the first rays of light on the influence of miRNAs in obesity and cancer interactions, since miR-17-5p would be later recognized by the scientific community to be a member of the most notorious oncogenic polycistronic miR cluster, namely, the miR-17-92 polycistronic cluster, with such members being highly upregulated in a wide spectrum of human cancer models , 48.Focusing on colorectal cancer, the level of influence by miRNA dysregulated activity has also been widely reported by the scientific community in the last 15 years, ever since the first reporting by Michael and colleagues in 2003 . Among tmiRNAs can also act as tumor suppressors within most human cancer models. This is also reflected in CRC, where a whole spectrum of miRNAs acts as regulators of the differing phenotype characteristics of CRC that make the tumor more aggressive and life threatening. The comprehensive review by Mizuno and colleagues gives a detailed representation of the Let-7 family of miRNAs that are typically downregulated in CRC cases . In addiThe scientific reporting of miRNA activities involved in regulating physiological and molecular pathway links between obesity and colorectal cancer (CRC) is relatively scarce, though such observations are evermore on the increase .The initial findings by Olivio-Marston and colleagues in 2014 examined the possibility of diet-induced obesity to have a tumorigenic effect on CRC within the azoxymethane murine model . In addiIn 2016, Meerson and Yehuda discovered a precise molecular interplay that placed miRNA activity as pivotal intermediates for the cross-communication between obesity and CRC . This stContinuing in this line of research, the investigations carried out by Tie and colleagues in 2017 revealed further details on the level of miRNA interplay with hypercholesterolemia and CRC . Employmγ) in obesity [γ expression level and degree of its promoter methylation [γ expression was also found to be downregulated within the same patient groups, consequently inferring the miRNA interplay to lead to increased CRC risks within patients through a downregulatory action by such a miRNA combination on PPAR-γ expression [Another scientific report of importance was the recent publication by Motawi and colleagues in 2017 . This st obesity . Blood shylation . The reshylation . Furtherpression .There are already a number of reputable industry leaders in miRNA therapies such as miRNA therapeutics, miRagen Therapeutics, Santaris pharma, or Regulus Therapeutics. They are currently entering clinical trials, using miRNAs for the treatment of several diseases, including cancer. The purpose of miRNA therapies is mainly using miRNAs that normally downregulate several target-oncogene, as possible drugs. The loss of function of these miRNAs might alter the expression of target-oncogene. Therefore, it could initiate tumor formation. These miRNAs should function as an inhibitor that antagonize (by sequence complementarity) the upregulated oncomiR in order to artificially lower the oncomiR's expression level to “normal” levels. Alternatively, the patient can be treated with miRNA mimics in order to artificially increase the expression levels of downregulated tumor-suppressor miRNAs. In both cases, a bespoke drug delivery system is employed to assure safe passage of such miRNA mimics/inhibitors through the bloodstream and allow uptake at the site of action .Approximately 20 clinical trials against cancer have currently been conducted using miRNA-based therapeutics . miRNAs The gene-miRNA-diet interaction could be a promising target to consider miRNA as drug therapies in the obesity-related cancer axis. A study conducted in prostate cancer cell lines found that genistein (isoflavone) was able to upregulate ADP–Ribosylarginine-Hydrolase (ARH1), a suppressor tumor, by downregulating miR-221 and miR-222 . CurcumiEnhancing awareness among the scientific community about the prospect of miRNA influences is crucial to consider miRNA therapies in obesity-linked colorectal cancer tumorigenesis and its clinical progression. Research articles pertaining to the identification and validation of such crucial miRNA biomarkers in this bespoke niche of cancer patients are still very low and, consequently, it is necessary to increase the spotlight and eventually increase the level of global research efforts for discovering novel miRNA influences of obesity-linked colorectal cancer. Ultimately, additional research will eventually lead to novel miRNA-based theragnostic tools that can benefit the cancer patient within the clinical setting in the not-too-distant future. Currently, we have enough knowledge about the role of miRNA as a diagnostic tool, but we must gather all the efforts to turn them into a therapeutic tool.Although miRNA-based therapeutics and diagnostics are still in their infancy, the degree of bespoke therapeutic efficacy and enhanced patient risk-stratification precision offered by such technology will certainly grow to the point where novel diagnostic kits and drug treatments for the treatment of all conditions influenced by miRNA dysregulations will become the mainstay clinical tools of the consultant oncologist by the end of the next decade. Recent technological advances could allow a high performance to obtain the specific profiles of miRNA (fingerprint) at a very precise level, in a cost-effective manner in the diagnosis, treatment, and monitoring of obesity and cancer. The low cost of data generating could lead us to the Big Data Era. The availability of these large datasets provides unprecedented opportunities but also poses new challenges for data mining and more accurate analysis.Even though the current level of evidence is at its infancy, epigenetics mechanism involved to regulatory elements influences within all aspects of human cell physiology pathways can never be underestimated. In this review, we aimed to shed light on merely how epigenetics modifications could induce molecular orchestration that interplays between obesity and colorectal cancer tumorigenesis and development. Within the short-term future, the authors are highly confident that further evidence will be revealed by the global scientific community to further confirm the paramount roles played by DNA methylation and miRNAs within the obese individual, both for inducing comorbidities and severe disease pathologies and for possible prophylaxis and treatment measures.


Guchengosuchus shiguaiensis, which is one of the stratigraphically oldest erythrosuchids and is known from a single partial skeleton from the lowermost Middle Triassic (lower Anisian) lower Ermaying Formation of Shaanxi Province, China. We provide a new differential diagnosis for Guchengosuchus shiguaiensis, and identify a series of autapomorphies relating to the morphologies of the skull roof and vertebrae. Incorporating updated anatomical information for Guchengosuchus into the most comprehensive morphological phylogenetic analysis available for early archosauromorphs recovers it as an early branching member of Erythrosuchidae, outside of the clade formed by Garjainia, Erythrosuchus, Chalishevia, and Shansisuchus. Fugusuchus hejiapanensis, from the uppermost Lower Triassic to lower Middle Triassic Heshanggou Formation of China, is recovered as the earliest branching member of Erythrosuchidae.Erythrosuchidae is a clade of early archosauriform reptiles, which were apex predators in many late Early and Middle Triassic ecosystems, following the Permo-Triassic mass extinction. Erythrosuchids had a worldwide distribution, with well-preserved fossil material known from South Africa, European Russia, and China. We here redescribe the anatomy and revise the taxonomy of  Erythrosuchidae is a clade of early archosauriform reptiles that comprises a small number of species ranging stratigraphically from the late Early to the Middle Triassic . ErythroGuchengosuchus shiguaiensis from the earliest Middle Triassic of Shaanxi, China : maxilla with 14 tooth positions and ankylothecodont tooth implantation; maxilla without maxillo-nasal tuberosity and antorbital fossa; nasal with series of three knob-like convexities dorsal to the facet for the postnarial process of the premaxilla*; parietal with dorsal surface of the base of anterolateral process bearing a subtriangular fossa that extends onto the frontal and is separated from the supratemporal fenestra by a raised edge*; pterygoid without palatal teeth; anterior–middle cervical vertebrae with a strongly transversely convex and rugose distal expansion of the neural spine*; accessory lamina subdivides the postzygapophyseal centrodiapophyseal fossae of the cervical and anterior dorsal vertebrae*; accessory articular surface for third head of cervical rib positioned at the same height dorsoventrally as the diapophysis*; and scapular blade with strongly concave posterior margin , Erythrosuchus africanus , and Chalishevia cothurnata (PIN 4366/1). The lateral surface of the maxilla is flat. The anterior process of the maxilla is anteroposteriorly short, representing approximately 35% of the total length of the bone as preserved. The dorsal margin of the anterior process and the anterior margin of the ascending process are continuous along a curve that is slightly concave in lateral view  and some specimens of Shansisuchus shansisuchus . By contrast, the anterior process is well distinguished from the ascending process by a clear inflexion in Garjainia prima , Erythrosuchus africanus , Shansisuchus shansisuchus . There is no indication of a facet for articulation with the premaxilla along this concave margin, which The main body of the maxilla is elongate and dorsoventrally narrow. Its ventral margin is very gently convex along the anterior process in lateral view, meaning that the anterior end of the tooth row is slightly upturned relative to the tooth row midpoint. The ventral margin of the maxilla along the horizontal process is straight, but this margin is concave in Garjainia prima (PIN 2394/5). The lateral thickening of the ascending process is considerably less developed than the probably homologous pillar-like maxillo-nasal tuberosity , Garjainia prima , Shansisuchus shansisuchus , and Chalishevia cothurnata (PIN 4366/1). The preserved ventral margin of the antorbital fenestra extends for around 24 mm and is slightly concave dorsally, resembling the condition in several basal archosauriforms . As a result, the horizontal process increases slightly in height posterior to the anterior border of the antorbital fenestra. Beyond this point the ventral margin of the antorbital fenestra is broken, so that the maxilla appears to generally taper in dorsoventral height toward its posterior end, but the true profile of the maxilla cannot be determined. At its posterior end, above crowns 11–14, the maxilla is slightly thickened below the area of articulation with the lacrimal and jugal, and this thickening extends from anterodorsal to posteroventral. No antorbital fossa is evident on either the main body of the maxilla or the posterior surface of the base of the ascending process, similar to the condition in Proterosuchus fergusi , Kalisuchus rewanensis (NM QR 3570), and Fugusuchus hejiapanensis  and Shansisuchus shansisuchus , by contrast, a well-developed antorbital fossa is present on the base of the ascending process and horizontal process. An antorbital fossa is also present in Erythrosuchus africanus (BP/1/5207), but is less extensive.The base of the ascending process is situated above crowns 2–5. Because of the damage to the anterior end of the maxilla, it is not possible to determine if there was a short edentulous section adjacent to the premaxilla, or to confirm the presence or absence of an anteriorly opening notch and/or groove. The ascending process is anteroposteriorly broad and slightly thickened at its posterior margin . This thty sensu  of Erythpanensis , fig. 22Erythrosuchus africanus, Garjainia prima, and Chalishevia cothurnata . Most of this anterior sheet is currently missing, but as figured by Euparkeria capensis: SAM-PK-K6050; Teleocrater rhadinus: Asilisaurus kongwe: Silesaurus opolensis: ZPAL Ab III/361/26). A similar, transversely compressed and laterally offset sheet is present posterior to the ascending process, forming the dorsal part of the main body of the maxilla, and bounding the antorbital fenestra ventrally. There are no foramina visible on the medial surface, and the palatal process is broken at its base. The preserved portion of the palatal process is situated immediately above the bases of the interdental plates, resembling the condition in several other archosauriforms . By contrast, this process is placed distinctly dorsal to the alveolar margin and adjacent to the anterodorsal margin of the bone in Erythrosuchus africanus , Asperoris mnyama (NHMUK PV R36615), and several archosaurs . The posterior end of the horizontal process is considerably thickened, and possesses a strongly dorsoventrally convex medial surface. A cluster of anterodorsally-to-posteroventrally oriented thin ridges occurs immediately above the bases of the interdental plates, at the level of the sixth to ninth alveoli. This striated surface represents the facet for reception of the posterolateral process of the palatine. The posterior tip of the horizontal process is also covered with a series of thin ridges. In this case, however, the ridges are longitudinal and mark the area of contact with the lateral process of the ectopterygoid, as also occurs in various other saurian reptiles . Dorsal to the thickening of the posterior end of the horizontal process there is a very deep, longitudinal groove that received the jugal and possibly also the lacrimal if the jugal did not participate in the border of the antorbital fenestra. The position of this facet suggests that the antorbital fenestra was relatively long anteroposteriorly.The majority of the medial surface of the main body of the maxilla is dorsoventrally convex, resulting in transverse thickening of the maxilla. A thickened ridge extends dorsally from the main body onto the posterior half of the medial surface of the ascending process. Anterior to this thickened ridge, the ascending process forms a transversely compressed and laterally offset sheet, resembling the condition in other archosauriforms , Erythrosuchus africanus (BP/1/5207: tooth count 11), Chalishevia cothurnata , Shansisuchus shansisuchus , Proterosuchus fergusi  and Prolacerta broomi , Kalisuchus rewanensis (QM F8998), Garjainia madiba (BP/1/5525) and referred specimens of Garjainia prima . By contrast, maxillary tooth implantation appears to be fully thecodont  in the holotype of Garjainia prima (PIN 2394/5), Erythrosuchus africanus , and eucrocopodan archosauriforms . Crowns are recurved, with their apices positioned distal to the distal margins of their bases, and labiolingually compressed. Fine mesial denticles are present, but are poorly preserved in most cases and appear to be restricted to the apical 30–40% of the crown. The distal denticles are generally better preserved, and appear to extend along almost the entire distal margin. The denticles have a rectangular outline in labial or lingual view. Enamel wrinkles and blood grooves are absent.A total of 14 teeth were present (assuming that the most anterior preserved crown was the most anterior in the complete specimen), a relatively low maxillary tooth count comparable to those for a broomi , proterouriforms , althougNasal. An incomplete left nasal is preserved (Garjainia prima (PIN 2394/5), but being considerably less strongly sculptured than in Asperoris mnyama , Shansisuchus shansisuchus (Garjainia prima (PIN 2394/5), or Erythrosuchus africanus . Accordingly, this condition appears to be an autapomorphy of Guchengosuchus.The lateral part of the external surface of the nasal forms the dorsal part of the lateral wall of the preorbital part of the skull, and thus would have faced mostly laterally and slightly dorsally. At the anterior end a small part of the posterodorsal margin of the external naris is preserved. Posteroventral to this, the external surface of the nasal between the external naris and the facet for the postnarial process of the premaxilla is gently concave. This concavity runs parallel to the facet for the postnarial process and is terminated posterodorsally by a short anteroposteriorly extending series of three knob-like rugosities  that aresisuchus , GarjainChalishevia cothurnata (PIN 4366/1), Shansisuchus shansisuchus (Erythrosuchus africanus (BP/1/5207). By contrast, in Garjainia prima the distal tip of the postnarial process of the premaxilla is comparatively broad (PIN 2394/5). Posteroventrally, a very narrow, almost flat surface, representing the lateral exposure of the descending process of the nasal, separates the facet for reception of the postnarial process of the premaxilla from the facet for reception of the ascending process of the maxilla (see Erythrosuchus africanus (BP/1/5207) and several other archosauriforms . By contrast, the descending process of the nasal is anteroposteriorly very broad in Garjainia prima (PIN 2394/5), Shansisuchus shansisuchus .Posteroventral to this concavity is the posterodorsally tapering facet for the postnarial process of the premaxilla. This facet is deepest anterodorsally, and becomes shallower posteroventrally. The facet is relatively narrow, suggesting that the postnarial process was also relatively narrow at its tip as in sisuchus , and Erysisuchus , and ChaPosterior to the descending process of the nasal there is a diagonal ridge, anteroventrally oriented, which delimits anteriorly the facet for reception of the ascending process of the maxilla. This facet becomes deeper posteriorly. As a result, the facet for reception of the ascending process of the maxilla is a medially inset, transversely compressed, ventrally descending sheet of bone situated slightly posterior to the facet for the postnarial process of the premaxilla. This surface for the maxilla is broken posteriorly. The posteriormost preserved part of the lateral margin of the nasal is grooved, perhaps for contact with the lacrimal. The internal surface of the nasal is transversely concave, with no notable ridges or foramina present.Frontal. The frontals are largely intact and preserved as part of the articulated section of skull roof, but their anterior ends are missing (Prolacerta broomi (BP/1/471), Teyujagua paradoxa , Tasmaniosaurus triassicus (Fugusuchus hejiapanensis (Erythrosuchus africanus (Shansisuchus shansisuchus (Euparkeria capensis (SAM-PK-5867). By contrast, the paired frontals are wider than long in Garjainia prima (PIN 2394/5). The dorsal surface of the most anteriorly preserved region of the frontal bears a few low longitudinal ridges. The facets for articulation with the prefrontals are not well preserved but may be situated at the anterolateral corners of the preserved portion of the frontals. The absence of a facet on the lateral surface of the frontal indicates that the bone contributed extensively to the dorsal border of the orbit, resembling the condition in most early archosauromorphs . By contrast, in other erythrosuchids the contribution of the frontal to the dorsal border of the orbit is very restricted or absent , but is flanked laterally by a pair of moderately deep depressions. By contrast, no inflated median area is present in Prolacerta broomi , “Chasmatosaurus” yuani (IVPP V4067), Fugusuchus hejiapanensis , or Euparkeria capensis (SAM-PK-5867). In Guchengosuchus shiguaensis the inflated area terminates anteriorly at a median depression. The inflated areas on the midline and adjacent to the orbital border define a shallow concavity on the frontal that becomes slightly deeper anteriorly. missing . The paiparadoxa , Proteropanensis : fig. 22a broomi , Proteropanensis , ErythroGarjainia prima (PIN 2394/5) and some specimens of Erythrosuchus africanus , and they meet the parietals along a suture that is poorly interdigitated medially. The parietals form a median, short subrectangular projection that extends anteriorly between the frontals. The lateral portion of the frontoparietal suture is strongly convex posteriorly, creating a posterior projection of the frontal resembling that present in Shansisuchus shansisuchus (IVPP V2508). The posterolateral corner of the frontal forms a laterally convex suture with the parietal and postfrontal, excluding contact between the frontal and the postorbital.The dorsal surface of the posterolateral corner of the frontal possesses a subtriangular depression that extends posteriorly onto the parietal and is well delimited anteriorly by a transverse tuberosity. Posteriorly, the paired frontals do not enclose a pineal fossa, contrasting with the condition in Shringasaurus indicus: ISIR 781, 789, 790; Prolacerta broomi: BP/1/2675; Tasmaniosaurus triassicus: Sarmatosuchus otschevi: PIN 2865/68). The latter ridge and the ridge that defines the anterior limit of the orbital depression bound a concave area at the anterolateral corner of the ventral surface of the frontal that is also present in some other basal archosauriforms . This condition differs from that in other erythrosuchids , and is hourglass-shaped. The olfactory tract opens anteriorly into a recess for the olfactory bulbs of the anterior brain, which is considerably anteroposteriorly longer than wide and laterally delimited by a ridge, as also occurs in other early archosauromorphs , Shansisuchus shansisuchus (IVPP V2508), and Erythrosuchus africanus (NHMUK PV R3592). This suture is V-shaped on the ventral surface of the skull roof of Guchengosuchus shiguaiensis. The postfrontal forms the posterodorsal corner of the orbit, and the ventral surface of the bone forms the posterior end of the orbital depression and is therefore slightly concave. The dorsal surface of the bone is slightly convex, and ornamented with low rugosities.parietal , but theParietal. The parietal possesses an anterolaterally projecting process that forms the anterior border of the supratemporal fenestra and articulates with the frontal and postfrontal , Garjainia prima (PIN 2394/5), Shansisuchus shansisuchus , Proterosuchus goweri (NM QR 880), and some specimens of Proterosuchus fergusi . The supratemporal fossa is not dorsally exposed, being restricted to the lateral and anterolateral borders of the supratemporal fenestra, but is dorsoventrally very deep. The posterior margin of the paired parietals forms a thick transverse eminence, as also occurs in other archosauromorphs  (Prolacerta broomi (BP/1/471), Teyujagua paradoxa (UNIPAMPA 653 cast), Proterosuchus fergusi (SAM-PK-K10603), Fugusuchus hejiapanensis (GMB V 313 photographs), Shansisuchus shansisuchus (Euparkeria capensis (SAM-PK-5867). By contrast, the posterolateral process acquires a wing-like appearance in occipital view with a strongly convex dorsal margin in Garjainia prima (PIN 2394/5) and Erythrosuchus africanus  . The possisuchus , fig. 6,fricanus . The antTasmaniosaurus triassicus: Erythrosuchus africanus: The ventral surface of the parietals possesses a deep concavity on the midline of the skull roof, representing the impression of the cerebrum. The concavity is laterally delimited by a thick tuberosity that separates it from the facet for reception of the capitate process of the laterosphenoid, as occurs in other archosauriforms , Fugusuchus hejiapanensis (Erythrosuchus africanus (BP/1/4645), and referred specimens of Garjainia prima . The occipital surface of the supraoccipital is concave lateral to the median ridge and becomes flat to gently convex toward the lateral margin of the bone, which is situated at the base of the paroccipital process. The suture between the supraoccipital and the otoccipital is discernible as a low shelf with a dorsolateral–ventromedial orientation. It is not possible to determine whether the supraoccipital contributes to the dorsal border of the foramen magnum or is excluded by a median contact between the otoccipitals. The midline portion of the dorsal surface of the supraoccipital forms a convex articular surface for contact with the ventral surface of the parietals. The lateral half of the dorsal surface of the supraoccipital has a rugose articular facet for the ventral surface of the base of the posterolateral process of the parietal. The anterior surface of the supraoccipital is strongly transversely concave, and articulates dorsolaterally with the prootic and ventrolaterally with the otoccipital. prootic . A sharpsisuchus , but is panensis , ErythroOtoccipital . The left otoccipital is largely intact , Garjainia madiba (Fugusuchus hejiapanensis (Erythrosuchus africanus (Sarmatosuchus otschevi (Fugusuchus hejiapanensis: Sarmatosuchus otschevi: Garjainia prima: PIN 2394/5). The dorsal surface of the paroccipital process is rugose. The anterior surface of the base of the paroccipital process articulates with the posterior process of the prootic. The lateral half of the anterior surface of the paroccipital process is weakly dorsoventrally convex, but the distal end of the anterior surface bears a shallow concavity for a loose contact with the posterior surface of the squamosal. The posteroventral margin of the paroccipital process is thin and sharp along its entire length.y intact , but is panensis : fig. 4botschevi . The parThe proximal half of the paroccipital process has a thin but well-developed ridge that extends distally from the base of the ventral ramus of the opisthotic and delimits the stapedial groove posteromedially. Only the base of the ventral ramus of the opisthotic, which divides the fenestra ovalis from the anteroposteriorly narrower metotic foramen, is preserved. The ventral ramus of the opisthotic expands slightly anteroposteriorly toward its ventral extremity. The facets for reception of the basioccipital are not preserved.Prootic. The left prootic is almost completely preserved , Shansisuchus shansisuchus (Garjainia prima (PIN 2394/5) also lack palatal teeth, but a referred specimen of Garjainia prima possesses two anteroposteriorly short rows of palatal teeth that extend onto the palatine (PIN 951/18).complete , but nowcomplete . This infricanus , UralosaGuchengosuchus shiguaiensis that are no longer preserved , Proterosuchus alexanderi (NM QR 1484), “Chasmatosaurus” yuani (IVPP V4067), Sarmatosuchus otschevi (PIN 2865/68), Garjainia prima (PIN 2394/5), and Erythrosuchus africanus (NHMUK PV R3592).The portions of the pterygoid of reserved , pl. 1.8reserved . The venMandible. The right articular and the posterior part of the right surangular are present and preserved in articulation . This shelf is better developed and has a more convex lateral edge in Garjainia prima , Erythrosuchus africanus (NHMUK PV R3592), Shansisuchus shansisuchus (Chanaresuchus bonapartei: PULR 07), and some pseudosuchians . A raised, posteriorly convex ridge of bone forms the posterior border of the glenoid. This ridge is separated by a deep, smooth concavity from the retroarticular process, as occurs in Proterosuchus fergusi (BSPG 1934 VIII 514), Garjainia prima (PIN 2394/5), referred specimens of Garjainia prima (PIN 951/33), and Garjainia madiba (NM QR 3051). The retroarticular process is relatively short and not upturned at its distal end, resembling the condition in Erythrosuchus africanus (Garjainia prima (PIN 2394/5). The medial surface of the retroarticular process displays the broken base of a dorsomedial projection. Behind the medial part of the posterior margin of the glenoid fossa is a ventromedial process that extends a very short distance medial to the medial edge of the fossa in dorsal view. An anteroposteriorly extending ridge on the ventral surface of the articular separates the facet for the angular on the ventrolateral surface from the facet for the prearticular on the ventromedial surface. The foramen for the passage of the chorda tympani is not preserved. The lateral surface of the retroarticular process is dorsoventrally concave and would have been covered by the posterior tip of the surangular.The articular forms most of the glenoid fossa and the retroarticular process. Almost all of the articular is artificially compressed and displaced, such that the glenoid fossa faces mainly medially. As a result of this distortion and the loss of the angular, the medial projection of the articular is artificially well exposed in lateral view. The glenoid fossa is transversely expanded and saddle-shaped, with a smaller lateral concavity separated by a low convexity from a larger and deeper medial concavity. The size discrepancy between the concavities suggests that the medial ventral condyle of the quadrate was considerably transversely wider than the lateral ventral condyle. By contrast, the ventral condyles of the quadrate are subequal in width in fricanus  and GarjVertebrae.Guchengosuchus shiguaiensis does not represent a juvenile individual. Preservation is relatively poor.Teyujagua paradoxa (UNIPAMPA 653 cast), Proterosuchus fergusi , and Euparkeria capensis (SAM-PK-5867). By contrast, the cervical centra are only slightly longer than tall in Sarmatosuchus otschevi (PIN 2865/68) and Garjainia prima (PIN 2394/5), and considerably anteroposteriorly shorter than tall in Erythrosuchus africanus (Shansisuchus shansisuchus (Sarmatosuchus otschevi (PIN 2865/68), Erythrosuchus africanus (BP/1/4680), Garjainia prima (PIN 2394/5), Prolacerta broomi (BP/1/2675), Proterosuchus fergusi (BSPG 1934 VIII 514), and Euparkeria capensis (SAM-PK-5867). The lateral surface of the centrum is deeply excavated, forming a deep centrodiapophyseal fossa ventral to the inferred position of the neurocentral suture and posteroventral to the diapophysis. This fossa undercuts the ventral surface of the diapophysis. The parapophysis is broken away on the right side, but on the left side is positioned on the anteroventral corner of the centrum and has fused to the capitulum of the cervical rib. There is no indication on either side of a third articular surface for the rib, although this area of the vertebra is not well preserved.The first cervical , Cuyosuchus huenei (MCNAM 2669), Erythrosuchus africanus . The prezygodiapophyseal lamina of Guchengosuchus shiguaiensis was probably originally placed further laterally to the base of the prezygapophysis before post-mortem compression. Although poorly preserved in this vertebra, this low thickening forms the anteroventral border of a shallow fossa on the lateral wall of the neural canal. This fossa represents a prezygapophyseal centrodiapophyseal fossa. Just ventral to the base of the neural spine, the lateral surface of the neural arch bears another deep fossa, which is bounded by the postzygodiapophyseal lamina, the weakly developed prezygodiapophyseal lamina, and a spinoprezygapophyseal lamina that extends from the posterior margin of the prezygapophysis onto the lateral surface of the neural spine. This is a spinodiapophyseal fossa and resembles the excavation present immediately lateral to the base of the neural spine in the postaxial cervical vertebrae of several other archosauromorphs, such as Protorosaurus speneri , Eorasaurus olsoni (PIN 156/108-110), Proterosuchus alexanderi (NM QR1484), Vonhuenia fredericki (PIN 1025/11), Garjainia prima (PIN 2394/5), Cuyosuchus huenei (MCNAM PV 2669), and Euparkeria capensis (SAM-PK-5867).The diapophysis is broken away on both sides, but its articular facet would have been set at the end of a ventrolaterally directed process, the base of which is placed approximately on the neurocentral suture, just anterior to the midlength of the centrum. The ventral orientation of the diapophyses is probably exaggerated by post-mortem transverse compression. A well-defined and thick postzygodiapopohyseal lamina arches posterodorsally from the base of the diapophysis to connect to the anterior margin of the postzygapophysis. A low posterior centrodiapophyseal lamina extends posteroventrally from the base of the diapophysis onto the posterodorsal portion of the centrum, forming the posterodorsal wall of the centrodiapophyseal fossa described above. The postzygodiapopohyseal lamina and the weakly developed posterior centrodiapophyseal lamina together frame a postzygapophyseal centrodiapophyseal fossa positioned posterior to the diapophysis and anteroventral to the postzygapophysis, as occurs in the cervical and dorsal vertebrae of several other archosauriforms , Teyujagua paradoxa (UNIPAMPA 653 cast), Garjainia prima (PIN 2394/5), some specimens of Proterosuchus fergusi  and Euparkeria capensis (SAM-PK-5867). The spine is inclined slightly anteriorly, an unusual condition among early archosauromorphs that also occurs in the anterior postaxial cervical vertebrae of Proterosuchus alexanderi (NM QR 1484) and some specimens of Proterosuchus fergusi (GHG 231). The neural spine expands anteroposteriorly toward its apex, the degree of expansion being greater in the anterior direction. The distal third of the spine also forms a strong transverse expansion, which is strongly rugose and dorsally convex. This rugose transverse expansion is well developed ventrally, extending along the distal third of the neural spine. This feature is also present in several isolated neural spines from the Lower Triassic Rewan Formation of Queensland (Teleocrater rhadinus (Yarasuchus deccanensis (ISIR 334). Anterior to the base of the spine is a well-developed spinoprezygapophyseal fossa bounded laterally by the prezygapophyses and dorsolaterally by the spinoprezygapophyseal laminae. The ventral part of this fossa is divided into left and right halves by an anterior, flange-like projection of the base of the neural spine. Posteriorly, a well-developed spinopostzygapophyseal fossa is placed between the postzygapophyses and extends onto the ventral half of the neural spine.The neural spine is anteroposteriorly broad and set above the posterior 80% of the centrum, resembling the condition in rhadinus  and YaraProlacerta broomi: BP/1/2675; Proterosuchus alexanderi: NM QR 1484; Chasmatosuchus rossicus: PIN 2252/381; Erythrosuchus africanus: Cuyosuchus huenei: MCNAM PV 2669; Teleocrater rhadinus: NHMUK PV R6795), in which the third facet is situated anteroventral to the diapophysis on a thick paradiapophyseal lamina. The third articular facet is separated from the diapophyseal facet by a small non-articular area, but lies adjacent to the anterior margin of the transverse process. A moderately thin lamina extends posteriorly from the base of the third articular facet and subdivides the centrodiapophyseal fossa of the centrum, extending as far posteriorly as does the base of the diapophysis. To our knowledge, this lamina is not present in other non-archosaurian archosauromorphs.The second cervical vertebra , and the early archosauriforms Cuyosuchus huenei (MCNAM 2669), Garjainia prima (PIN 2394/5-16), Erythrosuchus africanus . A paradiapophyseal lamina, if one was originally present, has broken away. The posterior centrodiapophyseal lamina extends longitudinally along the entire ventral surface of the transverse process and gives it a subtriangular cross-section, resembling the condition in Garjainia prima (PIN 2394/5-16). The facet of the diapophysis is subtriangular and strongly concave. A deep postzygapophyseal centrodiapophyseal fossa is present posterior to the diapophysis; it seems likely that prezygopophyseal centrodiapophyseal and centrodiapophyseal fossae were also present, although the area they would have occupied is damaged. A deep spinodiapophyseal fossa is present dorsal to the transverse process, resembling the condition in Erythrosuchus africanus (NHMUK PV R3592), but contrasting with the distinctly shallower fossa present in Garjainia prima (PIN 2394/5-16) and Garjainia madiba (BP/1/7135). Spinoprezygapophyseal and spinopostzygapophyseal fossae are present anterior and posterior to the base of the neural spine in Guchengosuchus shiguaiensis. An accessory, posteroventrally oriented lamina divides the postzygapophyseal centrodiapophyseal fossa, as also occurs in the cervical vertebrae. The prezygapophysis projects anterodorsally and its articular surface faces dorsomedially at around 45° to the horizontal; the postzygapophysis faces ventrolaterally at a similar angle. A well-preserved hyposphene with the same morphology as those of the cervical vertebrae is present posteriorly, resembling the condition in the dorsal vertebrae of Erythrosuchus africanus (NHMUK PV R3592) and Sarmatosuchus otschevi (PIN 2865/68). The neural spine is elongate and anteroposteriorly narrow; it widens slightly anteroposteriorly toward its apex, but considerably less than occurs in the cervicals. The morphology of this neural spine closely resembles that of the cervico-dorsal vertebrae of Garjainia prima (PIN 2394/5-16). The neural spine apex is rugose and slightly expanded transversely.The partial dorsal vertebra  includessisuchus : fig. 21A fragment of an additional vertebra  includesRibs. Four partial ribs are preserved . The anterior margin of the scapular blade (Euparkeria capensis (SAM-PK-5867), Garjainia prima , Proterosuchus alexanderi (NM QR 1484), “Chasmatosaurus” yuani (IVPP V2719), Sarmatosuchus otschevi (PIN 2865/68), and Cuyosuchus huenei (MCNAM 2669) the anterior margin of the scapular blade is convex and the posterior margin is posterodistally directed. Erythrosuchus africanus , Garjainia prima (PIN 2394/5), Garjainia madiba (BP/1/7152), and Sarmatosuchus otschevi (PIN 2865/68-37). A similar tuberosity or ridge is present at or very close to the base of the supraglenoid lip in several archosauriforms . The humerus (Garjainia madiba (BP/1/6232r), including in the presence of a squared-off distal end in lateral view. The distal end of the radius (Garjainia prima (Erythrosuchus africanus (Shansisuchus shansisuchus (Riojasuchus tenuisceps (PVL 3828). humerus  has stro humerus  is very e radius  is stronia prima , Erythrosisuchus , and theMetapodial (currently lost). A bone interpreted as a non-ungual phalanx by Guchengosuchus shiguaiensis was recovered within Erythrosuchidae, as the sister-taxon of a clade composed of the genus Garjainia and the Middle Triassic species Erythrosuchus africanus +  ; maxilla with lateroventrally facing neurovascular foramina on the lateral surface of the anterior and horizontal processes and extending ventrally as deep, well-defined grooves (character 53: 0→1); maxillary alveolar margin distinctly upturned on the anterior third of the bone  (character 70: 0→1); parietal with posterolateral process with a strongly transversely convex dorsal margin elevated from the median line of the posterior margin of the skull roof (character 169: 0→1); and radius with a strongly anteroposteriorly expanded distal end (character 438: 0→1). However, Bremer support for this branch is minimal, and the absolute and GC bootstrap frequencies are 58% and 53%, respectively.Our phylogenetic analysis recovered 27 MPTs of 3,585 steps, with a consistency index of 0.2519 and a retention index of 0.6477. As in a previous analysis by hurnata) . The ChiGarjainia and Middle Triassic erythrosuchids possesses the following synapomorphies that are absent in Guchengosuchus shiguaiensis: maxilla and nasal with a high maxillo-nasal tuberosity, delimiting anteriorly the antorbital fenestra or fossa, forming a distinct change of slope with the external surface of the anterior process (character 46: 1→2); maxilla with an antorbital fossa exposed in lateral view (character 54: 0→1/2); maxilla with a sub-vertical anterior margin of the base of the ascending process (character 58: 1→2); frontal with an only slightly constricted longitudinal canal for the passage of the olfactory tract and no olfactory bulb moulds and distinct semilunate posteromedially-to-anterolaterally oriented ridge on the orbital roof (character 120: 0→1); parietals with a pineal fossa on the median line of their dorsal surface (character 162: 0→1); surangular with a strongly laterally projecting shelf with a strongly convex lateral edge on the dorsolateral surface of the bone (character 286: 2→3); anterior cervical centra with a median, ventral longitudinal keel that extends ventral to the centrum rim in at least one vertebra (character 327: 1→2); and postaxial cervical vertebrae with a shallow, posterolaterally facing fossa ventral to the postzygapophysis (character 335: 0→1). This branch is very well supported, with a Bremer support of 4 and absolute and GC bootstrap frequencies of 82% and 78%, respectively.The branch that includes both species of Guchengosuchus shiguaiensis as the sister taxon of all other erythrosuchids (including Fugusuchus hejiapanensis), six steps to force its recovery as the sister taxon of Erythrosuchus africanus +  and eight steps to make it the sister taxon of Garjainia. Finally, six additional steps are needed to position Guchengosuchus shiguaiensis outside Erythrosuchidae, either as one of the closest sister taxa of Erythrosuchidae + Eucrocopoda or as the earliest branching member of Eucrocopoda.Under suboptimal searches, four additional steps are needed to place Guchengosuchus shiguaiensis. By contrast, the hypodigms of the Early Triassic erythrosuchids Fugusuchus hejiapanensis and Garjainia prima include fairly complete skulls  is also formed by the premaxilla and maxilla, but the nasal contributes substantially to the opening. Indeed, the secondary antorbital fenestra of Shansisuchus shansisuchus and Chalishevia cothurnata is in part a result of the presence of a long, non-articular margin on the anteroventral margin of the nasal, between the articular facets for the reception of the postnarial process of the premaxilla and the ascending process of the maxilla. This non-articular margin is absent in Guchengosuchus shiguaiensis, the articular facets of the premaxilla and maxilla being adjacent to each other. If an opening was present between the premaxilla and maxilla, as originally suggested by Decuriasuchus quartacolonia: Prestosuchus chiniquensis: Herrerasaurus ischigualastensis ; present but low, with a gradual transition with the external surface of the anterior process (1), present and high, with a distinct change of slope between it and the external surface of the anterior process (2). ORDERED.Character 393. Scapula, lateral tuber or ridge on the posterior edge: absent (0); present, just dorsal to the glenoid fossa (1); present, around the level of maximum anteroposterior narrowing of the scapular blade (2).Guchengosuchus shiguaiensis, Erythrosuchus africanus, Shansisuchus shansisuchus) is homologous with the tuberosity or ridge present immediately dorsal to the supraglenoid lip in several other archosauriforms . Guchengosuchus shiguaiensis (based on IVPP V8808): changed from (1: present) to (0: absent).Character 46 . Guchengosuchus shiguaiensis: changed from (0) to (1). Garjainia prima, Erythrosuchus africanus, Shansisuchus shansisuchus, Chalishevia cothurnata, and Batrachotomus kupferzellensis: changed from (1) to (2) because of the addition of a new character-state. See above for character-states.Character 56 . Guchengosuchus shiguaiensis (based on IVPP V8808): changed from (0: absent) to (-: inapplicable).Character 69 . Guchengosuchus shiguaiensis (based on IVPP V8808): changed from (0: absent) to (?: missing data).Character 393 . Guchengosuchus shiguaiensis . “Chasmatosaurus” yuani (based on IVPP V4067), Guchengosuchus shiguaiensis (based on IVPP V8808), Proterosuchus alexanderi (based on NM QR 1484), Proterosuchus fergusi (based on BSPG 1934 VIII 514): changed from  to .Scorings changed from the data matrix of 10.7717/peerj.6435/supp-1Supplemental Information 1Additional figures of the type material of Guchengosuchus, forming part of the raw data underpinning the manuscript.Click here for additional data file.10.7717/peerj.6435/supp-2Supplemental Information 2Raw data in TNT format for the phylogenetic analysis.Click here for additional data file.


Geographical mapping of dengue in resource-limited settings is crucial for targeting control interventions but is challenging due to the problem of zero-inflation because many cases are not reported. We developed a negative binomial generalised linear mixed effect model accounting for zero-inflation, spatial, and temporal random effects to investigate the spatial variation in monthly dengue cases in Bangladesh. The model was fitted to the district-level (64 districts) monthly reported dengue cases aggregated over the period 2000 to 2009 and Bayesian inference was performed using the integrated nested Laplace approximation. We found that mean monthly temperature and its interaction with mean monthly diurnal temperature range, lagged by two months were significantly associated with dengue incidence. Mean monthly rainfall at two months lag was positively associated with dengue incidence. Densely populated districts and districts bordering India or Myanmar had higher incidence than others. The model estimated that 92% of the annual dengue cases occurred between August and September. Cases were identified across the country with 94% in the capital Dhaka . Less than half of the affected districts reported cases as observed from the surveillance data. The proportion reported varied by month with a higher proportion reported in high-incidence districts, but dropped towards the end of high transmission season. A better understanding of spatial and temporal variation in dengue risk is invaluable since it guides intervention strategies and facilitates effective health resource allocation. Transmission of dengue depends on the distribution and abundance of the mosquito vectors which are sensitive to climatic and environmental factors including temperature, rainfall, and population density. By modelling dengue-climate relationships, the burden of dengue can be estimated in locations where data on transmission are not available permitting identification of high-risk areas. This reveals the extent of under-reporting in dengue surveillance data in resource-limited countries which is essential to estimating the changing burden of dengue. Aedes mosquitoes, predominantly Aedes aegypti and Aedes albopictus. The severe forms of the disease are potentially fatal. The World Health Organization (WHO) estimates that about 52% of the people at risk of dengue worldwide live in 10 countries of the WHO South-East Asia Region  credible interval [CrI]: 1.63, 6.04), while it’s negative interaction  with DTR indicates that increasing temperature and decreasing DTR is associated with increased dengue incidence. Mean monthly rainfall at two months lag showed a positive relationship  with dengue. Population density was significantly  associated with dengue. Districts not adjoining the borders with India or Myanmar were found to have significantly lower incidence compared with adjacent districts. The posterior density plots of fixed effect covariates are shown in p-value<0.0001) provided significant evidence against the null hypothesis of zero spatial autocorrelation in dengue cases in Bangladesh. Significance of the spatial effects were evident from the estimates of tau and kappa.A zero-inflation parameter with mean 0.08  confirms significant zero-inflation in reported dengue data. The Moran’s index . Transmission is spatially heterogeneous, with a higher number of cases estimated in the south compared to the northern districts, and the highest in Dhaka. An earlier study investigated space-time clusters of dengue transmission in Bangladesh from 2000 to 2009 and reported Dhaka as the most likely cluster throughout the study period, with a small number of secondary clusters in the south of the country in 2000 . June-NoOur model also identified districts with transmission that went unreported; during the high transmission month of August, cases were reported from less than 50% of the affected districts. We estimated that the reporting percentage  also varies by month. During the high transmission months, reporting is generally higher in districts with high compared to those with low transmission. However, towards the end of the high transmission season, proportion reported declined in majority of districts presumably due to the lower case numbers.A study measuring global burden of dengue estimated 4,097,833 symptomatic infections  in Bangladesh in 2010 [The strength of our model is the ability to generate estimates of dengue in areas with suspected under-detection. Relatively low case numbers indicate the potential of active transmission of the disease in a district which is crucial in the absence of information regarding the mosquito vector population. This is also indicative of increased transmission risk across the neighbouring districts resulting from inter-district movements of viraemic individuals. The assumption that transmission is governed by climatic suitability is reasonable, especially in the absence of effective public health strategies including mosquito control program. Our model was incapable of capturing the inter-annual variation in dengue and climate variables due to the aggregation of monthly counts over the study period which was required to model the monthly spread of dengue across the country.In conclusion, our study provides model-based estimates of spatial variation in monthly dengue cases across Bangladesh without compromising data for model fit. We believe that our findings provide a valuable assessment of the national dengue situation accounting for under-reporting. This study will contribute important information for prioritising and targeting dengue control and elimination interventions across Bangladesh.