In most parts of the world, microscopy is still the gold standard for diagnosing malaria. An online tool could help to improve your diagnostic skills

Malaria kills over one million people in Africa each year and contributes 10% of the continent's burden of disease [ 1 ]. One of the factors that affects the morbidity and mortality rate is incorrect diagnosis [ 2 ]. In this article, we describe a freely available online training tool for health professionals to learn malaria diagnosis. We describe why we launched it and discuss how it is being used.The Burden of Disease Malaria affects at least 200–300 million people every year and causes from 1–2 million deaths—mostly children under five and pregnant women in sub-Saharan Africa [ 1 ]. These deaths largely occur in remote rural areas with poor access to health services. In non-pregnant adults, although mortality rates are lower, the debilitating disease affects quality of life. The economic burden is also extremely high, accounting for a reduction of 1.3% in the annual economic growth rate of countries where malaria is endemic [ 3 ]. Malaria costs Africa more than US$12 billion every year in lost GDP, even though it could be controlled for a fraction of that sum [ 1 ]. Malaria is not limited to Africa—40% of the world's population is at risk of acquiring the disease [ 4 , 5 ]—and it is crucial for all physicians, medical scientists, and other healthcare professionals to be alert to the diagnosis. In addition, each year, 25–30 million people from non-tropical countries visit areas where malaria is endemic [ 6 ], and between 10,000 and 30,000 contract malaria [ 7 ]. Some 90% of infected travellers do not become ill until they return home; this “imported malaria” is easily treated, but only if it is diagnosed promptly [ 2 , 8 ].
The Burden of Disease
Malaria affects at least 200–300 million people every year and causes from 1–2 million deaths—mostly children under five and pregnant women in sub-Saharan Africa [ 1 ]. These deaths largely occur in remote rural areas with poor access to health services. In non-pregnant adults, although mortality rates are lower, the debilitating disease affects quality of life. The economic burden is also extremely high, accounting for a reduction of 1.3% in the annual economic growth rate of countries where malaria is endemic [ 3 ]. Malaria costs Africa more than US$12 billion every year in lost GDP, even though it could be controlled for a fraction of that sum [ 1 ].Malaria is not limited to Africa—40% of the world's population is at risk of acquiring the disease [ 4 , 5 ]—and it is crucial for all physicians, medical scientists, and other healthcare professionals to be alert to the diagnosis. In addition, each year, 25–30 million people from non-tropical countries visit areas where malaria is endemic [ 6 ], and between 10,000 and 30,000 contract malaria [ 7 ]. Some 90% of infected travellers do not become ill until they return home; this “imported malaria” is easily treated, but only if it is diagnosed promptly [ 2 , 8 ].The Importance of Correct Diagnosis Despite the efforts of a global campaign to roll back the disease, the number of deaths from malaria is increasing in Africa [ 9 ]. This statistic highlights the importance of local capacity to diagnose and treat malaria in order to prevent illness and death [ 10 ]. In many parts of the world, education about malaria diagnosis and treatment is limited—and the incorrect diagnosis of malaria by clinical, laboratory staff, and other healthcare workers can contribute to morbidity and mortality [ 2 , 11 ]. There is another important reason why correct diagnosis matters. Because of rising drug resistance in Africa, the conventional drugs for treating malaria—chloroquine and sulfadoxine-pyrimethamine—are now failing in up to 80% of cases [ 12 ]. There is a highly effective alternative to these drugs, which is artemisinin-based combination therapy (ACT) [ 13 ], but ACT is expensive (an adult dose of chloroquine costs around 10 cents, whereas a dose of ACT costs at least ten times that amount) [ 14 ]. Scaling up the use of ACT is now a core strategy in the global campaign to control malaria. But in order to control costs, and to prevent the emergence of resistance to ACT, its use should be targeted to real (rather than presumptive) cases of malaria [ 14 ]. Currently, however, a comparison of the number of parasitologically confirmed cases of malaria with those that are presumptively diagnosed shows high rates of overdiagnosis outside of hospitals at the community level, where self treatment is routine [ 14 ].
The Importance of Correct Diagnosis
Despite the efforts of a global campaign to roll back the disease, the number of deaths from malaria is increasing in Africa [ 9 ]. This statistic highlights the importance of local capacity to diagnose and treat malaria in order to prevent illness and death [ 10 ]. In many parts of the world, education about malaria diagnosis and treatment is limited—and the incorrect diagnosis of malaria by clinical, laboratory staff, and other healthcare workers can contribute to morbidity and mortality [ 2 , 11 ].There is another important reason why correct diagnosis matters. Because of rising drug resistance in Africa, the conventional drugs for treating malaria—chloroquine and sulfadoxine-pyrimethamine—are now failing in up to 80% of cases [ 12 ]. There is a highly effective alternative to these drugs, which is artemisinin-based combination therapy (ACT) [ 13 ], but ACT is expensive (an adult dose of chloroquine costs around 10 cents, whereas a dose of ACT costs at least ten times that amount) [ 14 ]. Scaling up the use of ACT is now a core strategy in the global campaign to control malaria. But in order to control costs, and to prevent the emergence of resistance to ACT, its use should be targeted to real (rather than presumptive) cases of malaria [ 14 ]. Currently, however, a comparison of the number of parasitologically confirmed cases of malaria with those that are presumptively diagnosed shows high rates of overdiagnosis outside of hospitals at the community level, where self treatment is routine [ 14 ].Microscopy as the Gold Standard for Diagnosis We still regard microscopy as the gold standard for the diagnosis and characterisation of malaria infection ( Figure 1 ). Modern “dipstick” technology and molecular techniques have emerged as an aid to diagnosis [ 13 , 14 ]. Some of these are useful particularly for  Plasmodium falciparum  [ 15 ]—although they are less effective for other species or for mixed infections [ 16 , 17 ]—but these techniques are often only available in larger hospitals, which are more likely to be able to afford them. Figure 1 Thin Film Micrograph Showing a Red Blood Cell Containing Two Ring-Form  P. vivax  Parasites
 P. vivax  rings have a large quantity of cytoplasm and a large chromatin dot, as well as occasional pseudopods. The red blood cells are normal, to 1.5× normal, sized, round, and contain fine Schüffner's dots, and they quite often contain multiple parasites. (Photograph: CDC/Dr Mae Melvin) Some authors have suggested that these new tests should not be considered a complete substitute for direct microscopic examination of blood smears [ 16 ]. We agree. While microscopy has limitations—morphology can be misleading if a patient has received partial treatment or incomplete prophylaxis, and in some locations a microscope (let alone a microscopist) can be rare—the new dipstick tests also have their flaws. For example, they must be stored correctly, used correctly, and interpreted correctly. There are concerns about the variability in the different tests' false positive and false negative rates and about their cost–benefit ratio. There are many supporters of the new dipstick technology, and as it improves and becomes more robust and reliable, it may well replace the microscope in practice. But for much of the world, the front-line diagnosis of malaria still remains in the hands of the reasonably trained microscopist. Analysis of DNA by the polymerase chain reaction (PCR) may be a useful tool for diagnosis of malaria when the results of conventional techniques are negative, especially since PCR allows accurate species identification [ 18 ]. And when compared with the “gold standard” of microscopy, PCR has a sensitivity and specificity of 100%, with a detection limit of just one  P. falciparum  or three  P. vivax  parasites per microlitre of blood [ 19 ]. However, in most areas with malaria transmission, limited financial resources, persistent subclinical parasitaemia, and inadequate laboratory infrastructure preclude PCR as a routine diagnostic method [ 20 ]. Even in affluent, nonendemic countries, PCR is not a suitable method for routine use. Capital investment and ongoing running costs are prohibitive for many laboratories, and certainly for the foreseeable future this technology will remain a tool for the more specialised services in the more affluent societies. At this stage, it is not considered a “routine” assay.
Microscopy as the Gold Standard for Diagnosis
We still regard microscopy as the gold standard for the diagnosis and characterisation of malaria infection ( Figure 1 ). Modern “dipstick” technology and molecular techniques have emerged as an aid to diagnosis [ 13 , 14 ]. Some of these are useful particularly for  Plasmodium falciparum  [ 15 ]—although they are less effective for other species or for mixed infections [ 16 , 17 ]—but these techniques are often only available in larger hospitals, which are more likely to be able to afford them.Some authors have suggested that these new tests should not be considered a complete substitute for direct microscopic examination of blood smears [ 16 ]. We agree. While microscopy has limitations—morphology can be misleading if a patient has received partial treatment or incomplete prophylaxis, and in some locations a microscope (let alone a microscopist) can be rare—the new dipstick tests also have their flaws. For example, they must be stored correctly, used correctly, and interpreted correctly. There are concerns about the variability in the different tests' false positive and false negative rates and about their cost–benefit ratio. There are many supporters of the new dipstick technology, and as it improves and becomes more robust and reliable, it may well replace the microscope in practice. But for much of the world, the front-line diagnosis of malaria still remains in the hands of the reasonably trained microscopist.Analysis of DNA by the polymerase chain reaction (PCR) may be a useful tool for diagnosis of malaria when the results of conventional techniques are negative, especially since PCR allows accurate species identification [ 18 ]. And when compared with the “gold standard” of microscopy, PCR has a sensitivity and specificity of 100%, with a detection limit of just one  P. falciparum  or three  P. vivax  parasites per microlitre of blood [ 19 ]. However, in most areas with malaria transmission, limited financial resources, persistent subclinical parasitaemia, and inadequate laboratory infrastructure preclude PCR as a routine diagnostic method [ 20 ]. Even in affluent, nonendemic countries, PCR is not a suitable method for routine use. Capital investment and ongoing running costs are prohibitive for many laboratories, and certainly for the foreseeable future this technology will remain a tool for the more specialised services in the more affluent societies. At this stage, it is not considered a “routine” assay.Teaching Microscopy Online In the hope of improving health professionals' understanding of malaria diagnosis, treatment, and prophylaxis, we launched an online malaria education tool that went live in July 1998 ( http://www.rph.wa.gov.au/labs/haem/malaria/index.html ). The materials are now available in English, French, and Spanish. One of the most important features is a “Test and Teach” section to allow microscopists to develop and sharpen their skills in malaria diagnosis ( Figure 2 ). Figure 2 A Clinical Case from the “Test and Teach” Section Because of regional variability in Internet access, we also made the tool freely available as a CD-ROM. The first CD-ROMs we produced, which were in English, reached institutions and centres in 41 countries during the first few months after the launch. By October 1999, we produced a new CD-ROM that incorporated a French translation of key areas of the project; a Spanish version followed. By the end of 1999, the CD-ROM version had reached over 70 countries and the website had received nearly 30,000 visitors. To date, the website has received more than 500,000 visitors. Around 83 million pages of text were downloaded from the website between July 2001 and September 2003. The CD-ROM version (over 8,000 copies) has been sent on request to institutions and centres in 149 countries, a number that does not include unauthorised (pirated) copies of the CD-ROM. The number of hits to the site (the number of pages or images of the site that are accessed) has risen dramatically, from 1,500 to over 100,000 per week.
Teaching Microscopy Online
In the hope of improving health professionals' understanding of malaria diagnosis, treatment, and prophylaxis, we launched an online malaria education tool that went live in July 1998 ( http://www.rph.wa.gov.au/labs/haem/malaria/index.html ). The materials are now available in English, French, and Spanish. One of the most important features is a “Test and Teach” section to allow microscopists to develop and sharpen their skills in malaria diagnosis ( Figure 2 ).Because of regional variability in Internet access, we also made the tool freely available as a CD-ROM. The first CD-ROMs we produced, which were in English, reached institutions and centres in 41 countries during the first few months after the launch. By October 1999, we produced a new CD-ROM that incorporated a French translation of key areas of the project; a Spanish version followed. By the end of 1999, the CD-ROM version had reached over 70 countries and the website had received nearly 30,000 visitors.To date, the website has received more than 500,000 visitors. Around 83 million pages of text were downloaded from the website between July 2001 and September 2003. The CD-ROM version (over 8,000 copies) has been sent on request to institutions and centres in 149 countries, a number that does not include unauthorised (pirated) copies of the CD-ROM. The number of hits to the site (the number of pages or images of the site that are accessed) has risen dramatically, from 1,500 to over 100,000 per week.Feedback from Users Through a circulated questionnaire with a 63% response rate, we have received feedback from users in 15 countries. Respondents said they valued the content, presentation, and usefulness of the online information. Who is using the material? A wide range of people—from students through to experienced personnel, and from clinicians to scientific, research, and technical staff. Many tropical medicine institutions have requested copies of the CD-ROM to supplement their own training programs. We have discussed the project at scientific conferences around the world and in scientific journals, advertising the fact that this educational material is freely available. Institutions wishing to obtain a free copy of the CD-ROM should contact E-mail:  Graham.Icke@health.wa.gov.au . We also became aware that unauthorised copies of the CD-ROM were being produced. Although there is a real need to guarantee the integrity of the information on the CD-ROMs and ensure proper credit for the authors and patrons, our main aim is to spread the “good word”, and such unauthorised copies are a powerful aid to distribution. Given that there is no need to recoup profit from this project, our only concern is its usefulness. Consequently, we have welcomed the production of these pirated copies, on condition that they were of good quality and were made freely available at no cost.
Feedback from Users
Through a circulated questionnaire with a 63% response rate, we have received feedback from users in 15 countries. Respondents said they valued the content, presentation, and usefulness of the online information. Who is using the material? A wide range of people—from students through to experienced personnel, and from clinicians to scientific, research, and technical staff. Many tropical medicine institutions have requested copies of the CD-ROM to supplement their own training programs. We have discussed the project at scientific conferences around the world and in scientific journals, advertising the fact that this educational material is freely available. Institutions wishing to obtain a free copy of the CD-ROM should contact E-mail:  Graham.Icke@health.wa.gov.au .We also became aware that unauthorised copies of the CD-ROM were being produced. Although there is a real need to guarantee the integrity of the information on the CD-ROMs and ensure proper credit for the authors and patrons, our main aim is to spread the “good word”, and such unauthorised copies are a powerful aid to distribution. Given that there is no need to recoup profit from this project, our only concern is its usefulness. Consequently, we have welcomed the production of these pirated copies, on condition that they were of good quality and were made freely available at no cost.Conclusion The Internet and associated technologies make it possible for educators with a desire to teach to contact those with a need to learn, regardless of the geographical distances involved. By enlisting assistance from international colleagues, language barriers can be overcome. In addition to the English, French, and Spanish versions, we are aware that our project has been translated into German, Thai, and Vietnamese and has been distributed through small regional health group networks. There can be little doubt that these new technologies have the potential to revolutionise information dissemination, with particularly significant implications for healthcare professionals in developing countries. The malaria educational program could be a model on which future health education programs are based. With rapidly increasing access to these new information technologies, health care professionals from anywhere in the world can now join the global health community.
Conclusion
The Internet and associated technologies make it possible for educators with a desire to teach to contact those with a need to learn, regardless of the geographical distances involved. By enlisting assistance from international colleagues, language barriers can be overcome. In addition to the English, French, and Spanish versions, we are aware that our project has been translated into German, Thai, and Vietnamese and has been distributed through small regional health group networks.There can be little doubt that these new technologies have the potential to revolutionise information dissemination, with particularly significant implications for healthcare professionals in developing countries. The malaria educational program could be a model on which future health education programs are based. With rapidly increasing access to these new information technologies, health care professionals from anywhere in the world can now join the global health community.


Background Waterpipe smoking is becoming a global public health problem, especially in the Eastern Mediterranean region (EMR).
Background
Waterpipe smoking is becoming a global public health problem, especially in the Eastern Mediterranean region (EMR).Methods We try in this study, which is a cross sectional survey among a representative sample of waterpipe smokers in cafes/restaurants in Aleppo-Syria, to assess the time period for the beginning of this new smoking hype. We recruited 268 waterpipe smokers (161 men, 107 women; mean age ± standard deviation (SD) 30.1 ± 10.2, response rate 95.3%). Participants were divided into 4 birth cohorts (≤ 1960, 1961–1970, 1971–1980, >1980) and year of initiation of waterpipe smoking and daily cigarette smoking were plotted according to these birth cohorts.
Methods
We try in this study, which is a cross sectional survey among a representative sample of waterpipe smokers in cafes/restaurants in Aleppo-Syria, to assess the time period for the beginning of this new smoking hype. We recruited 268 waterpipe smokers (161 men, 107 women; mean age ± standard deviation (SD) 30.1 ± 10.2, response rate 95.3%). Participants were divided into 4 birth cohorts (≤ 1960, 1961–1970, 1971–1980, >1980) and year of initiation of waterpipe smoking and daily cigarette smoking were plotted according to these birth cohorts.Results Data indicate that unlike initiation of cigarette smoking, which shows a clear age-related pattern, the nineties was the starting point for most of waterpipe smoking implicating this time period for the beginning of the waterpipe epidemic in Syria.
Results
Data indicate that unlike initiation of cigarette smoking, which shows a clear age-related pattern, the nineties was the starting point for most of waterpipe smoking implicating this time period for the beginning of the waterpipe epidemic in Syria.Conclusion The introduction of new flavored and aromatic waterpipe tobacco ( Maassel ), and the proliferation of satellite and electronic media during the nineties may have helped spread the new hype all over the Arab World.
Conclusion
The introduction of new flavored and aromatic waterpipe tobacco ( Maassel ), and the proliferation of satellite and electronic media during the nineties may have helped spread the new hype all over the Arab World.Maassel

Background Waterpipe smoking is becoming increasingly a worldwide phenomenon, with populations in the Eastern Mediterranean region (EMR) being especially affected [ 1 ]. This centuries-old tobacco use method comes under many different names (e.g., shisha, hookah, narghile, arghile), shapes, and sizes, depending on the region, with the term waterpipe implying a unifying feature of all these forms;  the passage of smoke through water before inhalation by the smoker  [ 2 ], Recent evidence shows that a quarter of some populations in the EMR currently smoke the waterpipe [ 3 ]. This trend is worrisome because of tobacco's known harmful effects to human health, and because prevailing norms the EMR may put certain slices of the society at increased risk of acquiring the habit, particularly women and children [ 6 , 7 ]. Although research on the health effects of waterpipe is still scarce, preliminary evidence links waterpipe use to respiratory, cardiovascular, and cancer diseases [ 8 - 11 ]. Developing effective intervention strategies to curb this emerging public health problem requires clear understanding of factors influencing the take up of this habit, as well its time course [ 1 ]. According to waterpipe smokers, the recent resurgence in waterpipe popularity is due to the introduction of  Maassel  (a specially prepared tobacco with sweetened fruit flavors and mild aromatic smoke), the media, and social trends [ 6 ]. Understanding the context in which these factors operate as well as being able to follow the secular course of the waterpipe epidemic requires estimation of the time frame for the beginning of the waterpipe hype. In this study we try to identify this time frame as well as provide evidence for the increase in waterpipe smoking.
Background
Waterpipe smoking is becoming increasingly a worldwide phenomenon, with populations in the Eastern Mediterranean region (EMR) being especially affected [ 1 ]. This centuries-old tobacco use method comes under many different names (e.g., shisha, hookah, narghile, arghile), shapes, and sizes, depending on the region, with the term waterpipe implying a unifying feature of all these forms;  the passage of smoke through water before inhalation by the smoker  [ 2 ], Recent evidence shows that a quarter of some populations in the EMR currently smoke the waterpipe [ 3 ]. This trend is worrisome because of tobacco's known harmful effects to human health, and because prevailing norms the EMR may put certain slices of the society at increased risk of acquiring the habit, particularly women and children [ 6 , 7 ]. Although research on the health effects of waterpipe is still scarce, preliminary evidence links waterpipe use to respiratory, cardiovascular, and cancer diseases [ 8 - 11 ].the passage of smoke through water before inhalation by the smokerDeveloping effective intervention strategies to curb this emerging public health problem requires clear understanding of factors influencing the take up of this habit, as well its time course [ 1 ]. According to waterpipe smokers, the recent resurgence in waterpipe popularity is due to the introduction of  Maassel  (a specially prepared tobacco with sweetened fruit flavors and mild aromatic smoke), the media, and social trends [ 6 ]. Understanding the context in which these factors operate as well as being able to follow the secular course of the waterpipe epidemic requires estimation of the time frame for the beginning of the waterpipe hype. In this study we try to identify this time frame as well as provide evidence for the increase in waterpipe smoking.MaasselMethods The current analysis is drawn from a survey conducted in 2003 among a representative sample of waterpipe smokers visiting cafes/restaurants in Aleppo, Syria. The survey details can be found elsewhere [ 12 ], but briefly a cross sectional interviewer-administered survey was conducted in 17 randomly selected (out of total 112) café/restaurants in Aleppo, Syria. Overall, 268 waterpipe smokers were recruited (161 men and 107 women; mean age ± SD 30.1 ± 10.2, age range 18–68 years; response rate 95.3%). Participants were asked about their waterpipe use frequency, cigarette smoking status, current age, age of initiation of waterpipe smoking, and age of initiation of daily cigarette smoking. The protocols and informed consent documents for this study were approved by the SCTS' IRB and the University of Memphis' IRB. The questionnaire was anonymous and informed consent was obtained prior to all interviews.
Methods
The current analysis is drawn from a survey conducted in 2003 among a representative sample of waterpipe smokers visiting cafes/restaurants in Aleppo, Syria. The survey details can be found elsewhere [ 12 ], but briefly a cross sectional interviewer-administered survey was conducted in 17 randomly selected (out of total 112) café/restaurants in Aleppo, Syria. Overall, 268 waterpipe smokers were recruited (161 men and 107 women; mean age ± SD 30.1 ± 10.2, age range 18–68 years; response rate 95.3%). Participants were asked about their waterpipe use frequency, cigarette smoking status, current age, age of initiation of waterpipe smoking, and age of initiation of daily cigarette smoking.The protocols and informed consent documents for this study were approved by the SCTS' IRB and the University of Memphis' IRB. The questionnaire was anonymous and informed consent was obtained prior to all interviews.Analysis First, year of birth was calculated by subtracting current age of participant from the year of survey (2003), while year of initiation of waterpipe smoking and daily cigarette smoking were calculated by adding the age of initiation of smoking to the year of birth. Year of birth was then divided into four decade-long categories (people born in/before 1960; during 1961–1970; during 1971–1980; in/after 1981), and year of smoking initiation into three decade-long categories (initiation in/before 1990, initiation during 1991–2000, and initiation in/after 2001). The Chi-Square test was used to assess differences between the three smoking initiation time-groups for each birth cohort, with  p  level <0.05 considered significant.
Analysis
First, year of birth was calculated by subtracting current age of participant from the year of survey (2003), while year of initiation of waterpipe smoking and daily cigarette smoking were calculated by adding the age of initiation of smoking to the year of birth. Year of birth was then divided into four decade-long categories (people born in/before 1960; during 1961–1970; during 1971–1980; in/after 1981), and year of smoking initiation into three decade-long categories (initiation in/before 1990, initiation during 1991–2000, and initiation in/after 2001).The Chi-Square test was used to assess differences between the three smoking initiation time-groups for each birth cohort, with  p  level <0.05 considered significant.pResults and conclusions Figure  1a,1b  compares between year of initiation of waterpipe and cigarettes among study participants, respectively, according to their birth cohort. It shows that while cigarette initiation displays an age-related pattern with peak initiation of participants occurring during in their twenties, most of waterpipe initiation and for all birth cohorts is commencing in the 1990s. Figure  2 , depicts number of waterpipe smokers according to their year of initiation, and suggests indirectly the rapid increasing trend of this smoking method. Taking into consideration possible limitations of this study, particularly the use of cross-sectional design to examine time trends and the relative youngness of the study sample, these results suggest that the current hype of waterpipe smoking is a recent one, commencing mostly in the nineties of the 20 th  century, and showing an increasing trend. Based on these results and our previous data regarding factors related to the spread of waterpipe [ 6 ], we present the following scenario for the current surge of popularity of waterpipe smoking. In the nineties,  Maassel  was introduced [ 13 ] simplifying waterpipe preparation and attracting more people to its mild aromatic smoke. Out of curiosity about this new tobacco or of modeling of others, people started experimenting with the waterpipe. The increasing number of waterpipe users together with the spread of satellite channels and electronic media, occurring during the same time period, may have contributed further to the creation and spread of this new smoking trend. Since waterpipe smoke contains considerable amounts of the addictive substance nicotine [ 14 , 15 ], nicotine dependence can sustain the habit among experimenters creating a stable base of waterpipe smokers within the society and contributing further to its spread. It remains to be seen, the possible role of resurgence of local identities in contrast to western culture in the adoption of this "oriental" method of smoking. The dramatic increase of this addictive smoking method within a short period of time and its potential health risks mandate that active surveillance and in depth research into its risk profile should become a priority for health systems in the EMR. Policy makers should also be alerted to this eminent public health threat, which is so far escaping current regulations and restrictions imposed on cigarettes, such as the ban on advertisement and the inclusion of health warnings on waterpipe tobacco products. Figure 1 a: Shows the proportion of current waterpipe smokers of different birth cohorts according to their year of initiation categorized into three decade-long categories. b. The same parameters are shown for cigarette smoking. Figure 2 Shows number of study participants according to their year of initiation of waterpipe smoking.
Results and conclusions
Figure  1a,1b  compares between year of initiation of waterpipe and cigarettes among study participants, respectively, according to their birth cohort. It shows that while cigarette initiation displays an age-related pattern with peak initiation of participants occurring during in their twenties, most of waterpipe initiation and for all birth cohorts is commencing in the 1990s. Figure  2 , depicts number of waterpipe smokers according to their year of initiation, and suggests indirectly the rapid increasing trend of this smoking method. Taking into consideration possible limitations of this study, particularly the use of cross-sectional design to examine time trends and the relative youngness of the study sample, these results suggest that the current hype of waterpipe smoking is a recent one, commencing mostly in the nineties of the 20 th  century, and showing an increasing trend. Based on these results and our previous data regarding factors related to the spread of waterpipe [ 6 ], we present the following scenario for the current surge of popularity of waterpipe smoking. In the nineties,  Maassel  was introduced [ 13 ] simplifying waterpipe preparation and attracting more people to its mild aromatic smoke. Out of curiosity about this new tobacco or of modeling of others, people started experimenting with the waterpipe. The increasing number of waterpipe users together with the spread of satellite channels and electronic media, occurring during the same time period, may have contributed further to the creation and spread of this new smoking trend. Since waterpipe smoke contains considerable amounts of the addictive substance nicotine [ 14 , 15 ], nicotine dependence can sustain the habit among experimenters creating a stable base of waterpipe smokers within the society and contributing further to its spread. It remains to be seen, the possible role of resurgence of local identities in contrast to western culture in the adoption of this "oriental" method of smoking. The dramatic increase of this addictive smoking method within a short period of time and its potential health risks mandate that active surveillance and in depth research into its risk profile should become a priority for health systems in the EMR. Policy makers should also be alerted to this eminent public health threat, which is so far escaping current regulations and restrictions imposed on cigarettes, such as the ban on advertisement and the inclusion of health warnings on waterpipe tobacco products.MaasselCompeting interests None declared.
Competing interests
None declared.Authors' contributions SR designed the study, conducted the analysis and wrote the first draft of the manuscript. KW and TE contributed to the design of survey and revision of the manuscript. WM contributed to the design of survey and wrote the final draft of the manuscript. All authors read and approved the final manuscript.
Authors' contributions
SR designed the study, conducted the analysis and wrote the first draft of the manuscript. KW and TE contributed to the design of survey and revision of the manuscript. WM contributed to the design of survey and wrote the final draft of the manuscript. All authors read and approved the final manuscript.Pre-publication history The pre-publication history for this paper can be accessed here:
Pre-publication history
The pre-publication history for this paper can be accessed here: