Genotypes and subgenotypes of bovine viral diarrhea virus (BVDV) field isolates from Japan, Germany and the United States of America (USA) were identified, and the prevalent pattern of BVDV in individual countries was estimated genetically. Subgenotypes were determined based on phylogenetic analyses of nucleotide sequences of a part of the E2-coding gene of BVDV. Forty-five, 61 and 56 BVDV strains were isolated from naturally infected cattle in Japan, Germany and USA, respectively, between 1980 and 2003. The most prevalent BVDV in these three countries was BVDV - 1b. The second most prevalent BVDV strains were 1a, 1d and BVDV - 2 in Japan, Germany and USA, respectively. The most prevalent subgenotype 1b in each country constructed individual small clusters in the subgenotype 1b branch in the phylogenetic tree. Although cattle and/or cattle products were moving among the three countries as part of international trade, the distribution of BVDV in the field in each country showed long-standing individual patterns.

Serological analysis was performed to detect morbillivirus infection in Kuril harbor seals in Hokkaido, Japan. Serum samples were collected from the seals at Nosappu (231 sera), Akkeshi (16), and Erimo (75) between 1998 and 2005. Antibodies to phocine distemper virus (PDV) were detected by ELISA in seals from Nosappu and Erimo. Antibodies to PDV were found in 56% (5/9) of the sampled seals from Nosappu in 1998, versus only 5% (3/66) for 2003, 1% (1/79) for 2004, and 1% (1/77) for 2005. These suggest epidemic caused by the virus in or before 1998. As antibody-positive seals included juvenile seals in 2003 and 2005, sporadic infections of the virus are thought to have occurred in recent years. In Erimo, antibodies to PDV were found in 50% (14/28) of sampled seals in 2004, versus only 13% (1/8) for 1999, 7% (1/15) for 2003, and 0% (0/24) for 2005. These suggest sporadic infection by the virus before 2003 and the epizootic between after autumn in 2003, when samples of 2003 were collected, and 2004. Since antibodies to canine distemper virus (CDV) were detected in one adult seal from Nosappu in each year from 2003 to 2005, sporadic infections of the virus, were suggested. There were no difference in incidence of seals with antibodies to the viruses between males and females and between juveniles and adults.