Distribution of the introduced cyprinid herpesvirus 3 in a wild population of common carp, Cyprinus carpio L.
Cyprinid herpesvirus 3 (CyHV-3), which causes a lethal disease in common carp, Cyprinus carpio L., and koi, C. carpio koi, first occurred in Lake Biwa, Japan in 2004. To elucidate distribution of CyHV-3 in a wild common carp population, we conducted a PCR survey of CyHV-3 among such fish in Lake Biwa in 2006. Only 6% (1/18) of the common carp smaller than 300 mm were positive with PCR, whereas 31% (18/58) of fish larger than 300 mm were positive. To evaluate their past exposure to CyHV-3 infection based on the presence of antibodies, we also measured the levels of serum anti-CyHV-3 antibodies in the carp, using an enzyme-linked immunosorbent assay. None (0/26) of the fish smaller than 300 mm was positive for the antibodies, whereas 54% (33/61) of fish larger than 300 mm were positive. Of the antibody-positive individuals, 44% (14/32) were also positive by PCR strongly suggesting that wild common carp that survived infection become CyHV-3 carriers. Five individuals were positive by PCR but negative for antibodies indicating that their infection with CyHV-3 had occurred recently. These results suggest that transmission of CyHV-3 from carriers to naïve common carp is still occurring in Lake Biwa.
Uchii
K
K
Research Institute for Humanity and Nature, Kitaku, Kyoto, Japan. kimi@chikyu.ac.jp
Matsui
K
K
Iida
T
T
Kawabata
Z
Z
D000818:Animals; D000914:Antibodies, Viral / Q000097:blood; D002347:Carps; D002353:Carrier State / Q000453:epidemiology / Q000276:immunology / Q000662:veterinary* / Q000821:virology; D004279:DNA, Viral / Q000737:chemistry / Q000235:genetics; D004797:Enzyme-Linked Immunosorbent Assay / Q000662:veterinary; D005393:Fish Diseases / Q000453:epidemiology / Q000276:immunology / Q000821:virology*; D006564:Herpesviridae / Q000235:genetics / Q000276:immunology*; D006566:Herpesviridae Infections / Q000453:epidemiology / Q000276:immunology / Q000662:veterinary* / Q000821:virology; D007564:Japan / Q000453:epidemiology; D016133:Polymerase Chain Reaction / Q000662:veterinary; D016036:Seroepidemiologic Studies
D000914:Antibodies, Viral; D004279:DNA, Viral