Epidemiological Survey of Bovine Viral Diarrhea Virus Isolated from the Offspring of Cows Moved to an Another Prefecture and the Eradication Efforts  in Tottori Prefecture

Tsuneyuki Masuda, Moegi Kuroda, Ken Iwao, Chiemi Ikemoto, Michiko Kodani, Yasumitsu Masuda, Ken-ichiro Kameyama, Yoshihiro Sakoda

Since 2012, efforts toward the eradication of bovine viral diarrhea virus (BVDV) have been undertaken in Tottori Prefecture because many persistently infected (PI) cows have been detected.  In 2016, six PI cows had been detected on three farms in Tottori Prefecture between January and October.  An epidemiological survey revealed that the inseminated dams of the six PI cows had been moved to the same ranch outside Tottori Prefecture during approximately the same period.  Using phylogenetic analysis of the 1122-base pair E2 gene sequence of BVDV isolated from five of the six PI cows, all five isolates were classified as BVDV-1c, with high nucleotide sequence homology (99.6-99.9%).  These results suggest that the dams of the six PI cows were infected with BVDV-1c during the insemination period and then gave birth to PI cows after returning to Tottori Prefecture.  As the route of invasion for PI offspring through inseminated cows moved to another prefecture demonstrated, BVDV eradication will require both local and interregional efforts.

J. Jpn. Vet. Med. Assoc.