Serological survey to determine the occurrence of malignant catarrhal fever infection in the Japanese small ruminant population from northern districts.

Ovine herpesvirus 2 (OvHV-2) causes sheep-associated malignant catarrhal fever (SA-MCF), and is responsible for economic losses in cattle and other susceptible species around the world. A survey of 154 serum samples from 14 flocks in 3 Japanese prefectures (Hokkaido, Aomori and Iwate) was undertaken between 2007 and 2008 to test for antibodies to OvHV-2. OvHV-2 was present in 56 sheep and 2 goats, with 37.66% of samples having a positive reaction using a serum neutralization test. The immune reaction reported in goats could result from Caprine herpesvirus-2. These results indicate that sheep are reservoirs for OvHV-2 in the field in Japan, and they might transmit the virus to susceptible cattle and wild fauna.