title: Molecular comparison of isolates of an emerging fish pathogen, koi herpesvirus, and the effect of water temperature on mortality of experimentally infected koi.
abstract: Koi herpesvirus (KHV) has been associated with devastating losses of common carp (Cyprinus carpio carpio) and koi (Cyprinus carpio koi) in North America, Europe, Israel and Asia. A comparison of virion polypeptides and genomic restriction fragments of seven geographically diverse isolates of KHV indicated that with one exception they represented a homogeneous group. A principal environmental factor influencing the onset and severity of disease is water temperature. Optimal growth of KHV in a koi fin cell line occurred at temperatures from 15-25 degrees C. There was no growth or minimal growth at 4, 10, 30 or 37 degrees C. Experimental infections of koi with KHV at a water temperature of 23 degrees C resulted in a cumulative mortality of 95.2 %. Disease progressed rapidly but with lower mortality (89.4-95.2 %) at 28 degrees C. Mortality (85.0 %) also occurred at 18 degrees C but not at 13 degrees C. Shifting virus-exposed fish from 13-23 degrees C resulted in the rapid onset of mortality.
mesh_terms: D000818:Animals; D002347:Carps; D002460:Cell Line; D004279:DNA, Viral / Q000032:analysis; D005393:Fish Diseases / Q000401:mortality* / Q000821:virology; D014644:Genetic Variation; D006564:Herpesviridae / Q000235:genetics* / Q000302:isolation & purification / Q000472:pathogenicity / Q000502:physiology; D006566:Herpesviridae Infections / Q000401:mortality / Q000662:veterinary* / Q000821:virology; D012150:Polymorphism, Restriction Fragment Length; D013696:Temperature; D014779:Virus Replication
chemical_list: D004279:DNA, Viral