Phylogenetic analysis of bovine viral diarrhea virus from nasal swab sample of persistently infected cattle in Republic of Korea

Bovine viral diarrhea virus (BVDV) is an economically important worldwide disease in livestock industry. In this study, the occurrence of BVDV in Korean indigenous cattle was performed by RT-PCR using nasal swab. Twelve of 21 cattle were identified as BVDV positive and classified as persistently infected (PI). These animals showed the occurrence of diseases such as diarrhea and pneumonia. BVDV PI outbreaks were found mostly in PI calves. Sequencing and phylogenetic analysis based on the 5'-untranslated region (UTR) showed that our case belonged to BVDV-2a. These results suggested that the nasal swab sampling was available method for the detection of PI animals, underscoring the need for BVDV control strategies in Korean indigenous cattle.