Department of General Systems Studies, The University of Tokyo, Meguro, Tokyo, Japan; Research Institute for Humanity and Nature, Kita, Kyoto, Japan.
FEMS Microbiol Ecol. 2014 Feb;87(2):536-42. doi: 10.1111/1574-6941.12242. Epub 2013 Nov 21.
Emerging infectious diseases are of growing concern in wildlife conservation and animal health. To better understand the consequences of these diseases, a key question lies in how they persist in host populations after they emerge. Using a gene expression approach, we investigated the mechanisms underlying the persistence of an emerging virus, Cyprinid herpesvirus 3 (CyHV-3), which has been spreading to wild populations of common carp (Cyprinus carpio) in Japan since 2003. Seasonal expression patterns of CyHV-3 genes in wild seropositive carp indicated that replication-related genes were transcribed only during the spring when water temperatures were permissive to CyHV-3 replication. In contrast, possible latency-related genes, which are expressed when CyHV-3 do not multiply, were also transcribed under nonpermissive conditions. These observations suggest that CyHV-3 may persist in carriers by establishing latent infection and then reactivating periodically coincident with the spring temperature increase when carp aggregate for mating, allowing successive virus transmissions between hosts during mating every year. Our results revealed that the life cycle of CyHV-3 may fit perfectly into the ecology of its host, resulting in the long-term persistence of this emerging virus in wild common carp populations.
新发传染病在野生动物保护和动物健康领域引起了越来越多的关注。为了更好地了解这些疾病的后果，一个关键问题在于它们在出现后如何在宿主群体中持续存在。我们使用基因表达方法研究了一种新发病毒——鲤鱼疱疹病毒 3（CyHV-3）持续存在的机制，该病毒自 2003 年以来一直在日本的野生鲤鱼种群中传播。野生阳性鲤鱼中 CyHV-3 基因的季节性表达模式表明，与复制相关的基因仅在春季水温有利于 CyHV-3 复制时转录。相比之下，在不进行复制时表达的可能与潜伏相关的基因也在非许可条件下转录。这些观察结果表明，CyHV-3 可能通过建立潜伏感染在携带者中持续存在，然后在春季温度升高时周期性地重新激活，当鲤鱼聚集交配时，允许每年在交配期间在宿主之间连续传播病毒。我们的研究结果表明，CyHV-3 的生命周期可能与宿主的生态环境完美契合，导致这种新发病毒在野生鲤鱼种群中长期存在。
