Tests are tentatively linking this summer's bottlenose dolphin die-off from New York to North Carolina to a specific virus, the National Oceanic and Atmospheric Administration said Tuesday.
Eleven of 33 samples have so far tested positive for cetacean morbillivirus, which can kill marine mammals but is not harmful to humans, NOAA officials said.
So far this year, there have been 488 bottlenose strandings reported in the mid-Atlantic region, including some on Long Island. That's more than three times the average in recent years, according to NOAA figures.
All but one of the 22 other test samples are suspected of having the naturally occurring virus, said Teri Rowles, who is heading NOAA's response to the strandings.
The virus was behind a 1987-1988 kill-off of more than 740 bottlenose dolphins from New York to Florida. Using that outbreak as a guide, Rowles said this one could continue through next spring.
Often transmitted through direct contact among animals or from inhaling respiratory particles, the virus affects lungs and the brain, resulting in animals developing pneumonia with accompanying respiratory problems.
Some animals develop antibodies, protecting them from future exposure, NOAA said.
Rowles said the current outbreak is probably the result of a critical mass of younger dolphins having little to no immunity.
Though morbilliviruses are not known to jump beyond related species -- one of them causes measles in humans and primates, and another, distemper in dogs and wolves -- people with open wounds should still steer clear of stranded dolphins, Rowles said, as the animals could also have secondary infections.
Hardest hit have been dolphins along the shores of Virginia, where 186 strandings have been reported this summer. There have been 72 in New Jersey and 26 in New York, according to NOAA.
From July through mid-August, 21 bottlenose strandings had been reported from the Rockaways to Montauk, including one in Coney Island, according to the Riverhead Foundation for Marine Research and Preservation.