A recent study sheds light on a disease that has caused widespread damage to farmed salmon in Norway and the United Kingdom.
Heart and skeletal muscle inflammation (HSMI) was first detected in salmon on a farm in Norway in 1999 and has now been reported in 417 fish farms in Norway and the UK. The disease destroys heart and muscle tissue and kills up to 20 percent of infected fish. Recent efforts to identify the pathogen causing the disease have been unsuccessful.
The study was conducted by an international team of researchers led by W. Ian Lipkin, an epidemiology professor and director of the Center for Infection and Immunity at Columbia University’s Mailman School of Public Health.
Published online in the journal PLos One, the study found evidence that the disease may be caused by a previously unknown virus. The newly identified virus is related but distinct from previously known reoviruses.
The study says that while there is no evidence that the virus could spread to humans, it is a threat to aquaculture and it has the potential to spread to wild salmon.
Of the 29 salmon representing three different HSMI outbreaks and 10 samples from healthy farmed fish, 28 of the 29 known HSMI samples and none of the 10 healthy samples were positive. Investigators also tested 66 samples obtained from wild salmon living in nine coastal rivers in Norway, 16 of which has traces of the virus, though in generally lower concentrations than found in ailing farmed fish.
Work has already begun in Norway to develop a vaccine.
