Longitudinal study of bovine rotavirus group A in newborn calves from vaccinated and unvaccinated dairy herds

Abstract

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.

Longitudinal surveillance of rotavirus A genotypes circulating in a high milk yield dairy cattle herd after the introduction of a rotavirus vaccine

“…In this study, dsRNA to from the RVA was identified in 5.9% (51/863) of the fecal samples with scores of 0 or 1 and in 12.5% (26/208) and 14.8% (22/149) of the fecal samples with scores of 2 and 3, respectively. Although RVA was more frequent in diarrheic calves, the overall frequency of RVA diagnosis was lower than that observed in unvaccinated herds (Rocha et al, 2017).…”

“…The percentage of RVA-positive fecal samples obtained during this study was 8.1% (99/1220). Other longitudinal studies that have been conducted in Brazil to determine the level of RVA infection in calves born from vaccinated dairy cows had percentages of RVA-positive diarrheic fecal samples that were 5.7% (49/850) (Coura et al, 2015) and 3.9% (11/281) (Rocha et al, 2017).…”

Synanthropic rodents as virus reservoirs and transmitters

“…RVs are widely distributed in Brazil, and have been described in animals (both young and adults) such as cattle 105 , birds 106 , and pigs 107,108 . In rodents, there is a single report of RVA associated with swine production 109 .…”

Phylogenetic Analyses of Rotavirus A from Cattle in Uruguay Reveal the Circulation of Common and Uncommon Genotypes and Suggest Interspecies Transmission

“…In this study, we observed a similar frequency of RVA detection in calves from vaccinated and unvaccinated herds. Failure in the protection against RVA infection by the vaccine was reported in studies conducted in Argentina and Brazil [ 34 , 35 , 36 , 37 ]; although vaccines are not effective in preventing RVA infection, they significantly reduce morbidity, the severity of diarrhea, and mortality related to RVA [ 38 ].…”