Prevalence of Bovine Viral Diarrhea Virus Infection in Dairy Herds of Nepal

Background: The Bovine Viral Diarrhea Virus (BVDV) infection causes reproductive and respiratory disease in cattle and buffaloes and is an economically important livestock disease across the world. In Nepal, cattle and buffalo farming is an important source of income for a majority of farmers. Infectious reproductive and respiratory diseases are common in Nepalese dairy herds and a large proportion of these cases remains undiagnosed. The burden of BVDV in Nepal is unknown. The objective of this pilot study was to determine the prevalence of persistent BVDV infection in dairy cattle in two commercially important livestock districts of Nepal. Materials and Methods: In total, 240 ear notch samples (153 samples from Chitwan and 87 samples from Kavrepalanchowk) from 60 dairy herds (30 herds in each district) were collected from cattle and buffaloes from December, 2014 through April, 2015. Questionnaire surveys were conducted to collect information on demographics and farm characteristics. Results: The farm-wise prevalence was 3.3% (95% CI: 0.1-17.2%) in Chitwan and 10.0% (95% CI: 2.1-26.5%) in Kavrepalanchowk, whereas individual animal prevalence was 0.7% (95% CI: 0.0-3.6%) in Chitwan and 3.4% (95% CI: 1.2-9.7%) in Kavrepalanchowk. Questionnaire survey indicated overall poor biosecurity in dairy farms and use of natural insemination for breeding with bulls of unknown origin, which may contribute to the spread of BVDV infection. Conclusion: This pilot study indicates circulation of BVDV and the presence of persistent infections in dairy herds in Nepal. It is suggested that the Nepal government and commercial dairy farmers include BVDV in regular surveillance and diagnostic activities.