Oyster herpes: Latest symptom of global warming?

New strain can kill 80 percent of an oyster bed in a week, experts say.

By Rachel Kaufman for National Geographic News
Published August 6, 2010 Don’t worry — oyster herpes isn’t a new side effect of eating “the food of love.” The incurable, deadly virus is, however, alarming fishing communities in Europe, where oyster herpes seems to be spreading—and could go on spreading as seas continue to warm, experts say. (Also see “Fish-killing Virus Spreads to Lake Superior.”) In July lab testing of farmed oysters detected the first known United Kingdom cases of herpes in the shellfish. The virus has already killed between 20 to 100 percent of breeding Pacific oysters in some French beds in 2008, 2009, and 2010, according to the French Research Institute for Exploitation of the Sea (Ifremer). The reason for oyster herpes’s emergence in Pacific oysters off England remains a mystery, though global warming may have played a part, experts speculate. A new strain named Ostreid herpesvirus 1 (OsHV-1) μvar (mew-var), the virus remains dormant until water temperatures exceed 16 C [61 degrees F], which U.K. waters reach in the height of summer, according to Kevin Denham of the British government’s Fish Health Inspectorate. With that in mind, Tristan Renault, director of Ifremer’s genetic and pathology lab, said that global warming “could be an explanation of the appearance of this particular type of the virus.” Though all herpes strains are DNA-based viruses, herpes, which infects everything from cows to clams to monkeys, comes in a wide variety of species, each with their own unique set of symptoms. Among humans, perhaps the best known forms are the Herpes simplex viruses, which are spread through close contact and can manifest themselves as oral and genital blisters. Ostreid herpes viruses are known to affect not only oysters but also clams, scallops, and other mollusks, according to Renault. …