Salmo salar 300x124 Case Closed on Salmon Mystery DiseaseThere was a lot of mystery surrounding a disease which was rampaging through European Salmon farms, a disease which was wasting their hearts and muscles. Finally, through the use of Genome sleuthing, the mystery has been solved.

The disease is caused by a previously unknown virus. This identification does not mean that there is now also a cure for the disease, however it is a great step forward into solving the problem. Now that scientists have pinned down the disease and the genome, it is only a matter of time before a cure will be found.

“It’s a new virus. And with this information now in hand, we can make vaccines,”
explained director of Columbia Univerity’s Center for Infection and Immunity, Ian Lipkin.

A couple of years ago, some Norwegion fisheries got into touch with Lipkin and asked for his aid in discovering what was going on in their Norwegion Salmon farms. They wanted to know what was causing the HSMI (Heart and Skeletal Muscle inflammation), the scientific name for an affliction which was identified in 1999 on one of their farms.

The fish which are infected are physically stunted, and have muscles so weak that they often have trouble swimming about, or even circulating blood around their bodies. This disease often results in death, so there is a great cause or concern. The reason there is so much concern is that the original outbreak was followed by 417 other in Norway and the United Kingdom, and every year there are more reports of the disease.. What is even more disturbing is that there have been reports of wild salmon being infected, which means that salmon which escape the farm are infecting the already low numbers of wild stocks. If something is not done to fix this problem, it could quite possibly spiral out of control, and have a devastating effect on not only local ecosystems but on the entire salmon market as we know it. “If the potential hosts are in close proximity, it goes through them like wildfire,” said Lipkin.

Lipkin and his team, which have already had great success in identifying mystery viruses, rigorously examined samples taken from infected salmon pens. They were looking for the DNA sequences which resemble sequences found in other viruses, and hopefully finding the HSMI-causing sequence. Lipkin compared the grueling process akin to solving a Sunday paper crossword. The researchers eventually found what they were looking for, and dubbed the virus piscine reovirus, or PRV. The virus was unveiled and explained in the issue of Public Library of Science one, published on the 9th of July.

Some viruses which are rather similar have been discovered on poultry farms, and cause muscle and heart disease in chickens. “Analogies between commercial poultry production and Atlantic salmon aquaculture may be informative,” The researchers wrote in the article. “Both poultry production and aquaculture confine animals at high density in conditions that are conducive to transmission of infectious agents.”

The results from these investigations might just be useful when the Obama administration comes up with its national policy for regulating aquaculture.