Longitudinal study of bovine rotavirus group A in newborn calves from vaccinated and unvaccinated dairy herds.
Reports of rotavirus excretion in calves usually result from cross-sectional studies, and in face of the conflicting results regarding protection of calves born to vaccinated dams against diarrhea, the aim of the present study was to evaluate rotavirus excretion in dairy calves born to vaccinated or unvaccinated dams, to identify the genotypes of bovine rotavirus group A (RVA) strains isolated from these animals as well as to investigate characteristics of the disease in naturally occurring circumstances throughout the first month of life. Five hundred fifty-two fecal samples were taken from 56 calves, 28 from each farm and, in the vaccinated herd, 11/281 samples (3.91%) taken from six different calves tested positive for RVA while in the unvaccinated herd, 3/271 samples (1.11%) taken from 3 different calves tested positive. The genotyping of the VP7 genes showed 91.2% nucleotide sequence identity to G6 genotype (NCDV strain), and for the VP4 gene, strains from the vaccinated herd were 96.6% related to B223 strain, while strains from the unvaccinated herd were 88% related to P[5] genotype (UK strain). Genotypes found in this study were G6P[11] in the vaccinated herd and G6P[5] in the unvaccinated herd. All calves infected with rotavirus presented an episode of diarrhea in the first month of life, and the discrepancy between the genotypes found in the commercial vaccine (G6P[1] and G10P[11]) and the rotavirus strains circulating in both vaccinated and unvaccinated herds show the importance of keeping constant surveillance in order to avoid potential causes of vaccination failure.
['Rocha|Thaís Gomes|TG|', 'Silva|Fernanda Dornelas Florentino|FD|', 'Gregori|Fábio|F|', 'Alfieri|Amauri Alcindo|AA|', 'Buzinaro|Maria da Glória|MD|', 'Fagliari|José Jurandir|JJ|']
D000818:Animals D000831:Animals, Newborn D001483:Base Sequence D002417:Cattle D002418:Cattle Diseases D003430:Cross-Sectional Studies D003967:Diarrhea D005243:Feces D005838:Genotype D008137:Longitudinal Studies D010802:Phylogeny D012401:Rotavirus D012400:Rotavirus Infections D022243:Rotavirus Vaccines D014611:Vaccination
Dairy calves RVA VP7 gene Sequencing VP4 gene Calf diarrhea