viral hemorrhagic septicemia (VHS)
(Novirhabdovirus viral hemorrhagic septicemia)

Overview

Common Names

Viral hemorrhagic septicemia virus, VHSv, VHSv Type IV-b, Egtved disease

Description

Viral hemorrhagic septicemia is a viral fish disease caused by the viral hemorrhagic septicemia virus (VHSv) of the rhabdovirus family. Symptoms of infected fish may include hemorrhaging (especially evident at fin margins, eyes, in the body cavity, etc.), darkened coloration, bloated abdomen, "popeye" (exophthalmia), lethargy or abnormal swimming and darting, and have the potential for high mortality

Habitat and Habits

VHS was historically a coolwater disease caused by several distinct strains of VHSv, each strain occupying a different region of the globe and infecting slightly different groups of host fish species. The Great Lakes strain is designated Type IV-b and has been shown to infect some warmwater species, causing kills up to approx. 70 degrees F. It is inactive at higher temperatures and thus cannot infect humans.

Susceptible Species

Species observed to have been killed by Type IV-b now include lake trout, steelhead trout, chinook salmon, yellow perch, round goby, emerald shiner, muskellunge, whitefishes, and walleye

Ecological Threat

The first detection of VHS on the Great Lakes was in 2005 in Lake Ontario. Following that, an archived muskellunge specimen that had been collected in 2003 tested positive, making it the earliest confirmed case. Type IV-b was initially considered a “low” mortality strain of VHSv, but then went on to cause massive kills of several Great Lakes fish species in spring 2006. In response, the US Department of Agriculture’s Animal and Plant Health Inspection Service (APHIS) imposed a federal order in late 2006 restricting international and interstate transport of susceptible species within or out of the at-risk region (i.e., states and provinces bordering the Great Lakes and St. Lawrence River). Some individual states to which the order applied imposed their own regulatory responses to also limit intrastate transport of susceptible fishes; check with state management agencies for the current regulations in your own state. Fish kills effecting multiple susceptible species should be reported to state management agencies. And never move live fish (including bait) from one body of water to another.

Invasive Listing Sources

No reference that we have lists this species as invasive in North America. This species is included for comparison to other species that are considered invasive.