Epidemiological observations of bovine viral diarrhea virus in Korean indigenous calves.

Bovine viral diarrhea virus (BVDV) is an important worldwide disease in the livestock industry. To date, little research has been done on BVDV circulating in the Republic of Korea (ROK). The cases outlined in our research originated from rectal swabs taken from calves up to 80 days of age. Twenty-two of 99 Korean indigenous calves with diarrhea were identified as BVDV positive and 3 different 5'-untranslated region (UTR) sequences were determined. The results indicated that BVDV infections in the ROK were found mostly in winter and when calves were less than 20 days old. Phylogenetic analysis based on the 5'-UTR revealed that our cases from Korean indigenous calves belonged to BVDV-2a. Therefore, the result of this study will be useful to understand epidemiology and allow producers in the ROK to better protect their livestock.