Abstract:
Bovine respiratory syncytial virus (BRSV) is one of the most important respiratory pathogens
of cattle. In this study, frequency of infection, analysis of variants, and the immune status of vaccinated and non-vaccinated cattle were studied. Blood (n = 162) and nasal/oropharyngeal (n = 277)
swabs were collected from 62 cattle herds in Turkey. Lung samples (n = 37) were also taken from
dead animals and abattoirs. Antibodies to BRSV were detected in 76 (46%) out of 162 sera. The
antibody levels in the vaccinated and non-vaccinated groups were statistically significant. Among
277 nasal/oropharyngeal swabs and 37 lungs, ten nasal/oropharyngeal and four lung samples were
positive for BRSV-RNA. BRSV-G gene sequences of 5 out of 14 RT-PCR positive samples showed
that all viruses clustered as Group-III in phylogenetic analysis with 88–100% homology. Similarity
with previous Turkish BRSVs was 89–98%, and that with BRSVs detected in the USA and Czechia
was 89.47–93.12%. BRSV continues to circulate in Turkish cattle, and vaccination seems beneficial in preventing BRSV. The diversity of the BRSVs found in this study needs be considered in
vaccination strategies.
