| 要旨トップ | 目次 | 日本生態学会第59回全国大会 (2012年3月,大津) 講演要旨
ESJ59/EAFES5 Abstract


一般講演(口頭発表) F2-13 (Oral presentation)

Seasonal and spatial distribution of Cyprinid herpesvirus 1 and Cyprinid herpesvirus 2 in Lake Biwa, Japan

*Honjo, M. N., Minamoto, T, Kawabata, Z. (Res. Inst. Human & Nat.)

Cyprinid herpesvirus 1 (CyHV-1) is a DNA virus which infects common carp and koi (Cyprinus carpio), resulting in high mortality in fish younger than 2 months of age. Cyprinid herpesvirus 2 (CyHV-2) infects goldfish (Carassius auratus L.) reared in aquaculture, causing high mortality in all size classes.

To determine the prevalence of these viruses in aquatic environments, we established a method for quantifying CyHV-1 and -2 DNA. Water samples were collected from 22 sites in Lake Biwa, Japan from 2008 to 2010 and were concentrated prior to analysis. CyHV-1 and -2 were detected in 5.2% and 4.9% of the samples and had a maximum concentration of 1.2 x 103 and 7.4 x 102 copies DNA/L, respectively. CyHV-1 was detected with high frequency from February to June 2010 and from sampling points with water temperatures of 10 to 25oC, which is the temperature range of viral replication. Moreover, compared to other zones of the lake, CyHV-1 showed higher concentrations in the reed zone. These results suggest that CyHV-1 is prevalent at breeding sites during the breeding season and may affect wild carp populations. On the other hand, CyHV-2 was detected with relatively higher frequency in 2009 but did not show any seasonal or spatial patterns. The presence of CyHV-2 suggests that the virus and/or goldfish are introduced to and present in Lake Biwa from aquaculture effluent.


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