Morbillivirus epidemic : a threat for the St. Lawrence beluga ?
In 1988-1989, after a morbillivirus epidemic, 17 000 seals were found dead on the European coastline. The same strain of virus also killed hundreds of dolphins and porpoises in Europe and along the East coast of the United States. Is the St. Lawrence beluga whale at risk?
To go through the looking glass
Blood samples from St. Lawrence seal and cetacean carcasses have been analysed for the presence of antibodies of certain strains of morbillivirus.
Seals examined before 1999 had antibodies for the seal morbillivirus implying that they had been exposed to the virus. In the meantime, only one case of distemper, the illness caused by the virus, has been reported and that was a beached harp seal on Prince Edward Island in 1991.
Furthermore, none of the 30 beluga examined during the same time period had the antibody for morbillivirus. There are two possible explanations for this: 1) beluga whales have not yet been exposed to the virus or 2) they are resistant to it. In the first case, the St. Lawrence beluga population would be extremely susceptible if they were to come in contact with the virus. Due to the small size of this population, an epidemic caused by the virus could bring about its extinction. In order to evaluate these risks for the beluga, scientists wish to obtain a larger number of samples from other cetaceans in the St. Lawrence. This will help determine whether certain species form a kind of reservoir for morbillivirus.
Lena Measures Maurice Lamontagne Institute/Fisheries and Oceans Canada, Ole Nielsen, Fisheries and Oceans Canada, Daniel Martineau Faculty of Veterinary Medicine at Université de Montréal and Pierre-Yves Daoust, Atlantic Veterinary College in Charlottetown.
Saguenay–St. Lawrence Marine Park, St. Lawrence Action Plan – Vision 2000, Faculty of Veterinary Medicine at Université de Montréal, Atlantic Veterinary College, Charlottetown, and Les Industries Filmar, Bic.