A measleslike virus appears to be the chief cause of the droves of dead dolphins that have washed ashore along the Eastern Seaboard of the United States this summer, researchers announced yesterday. Since 1 July, 333 bottlenose dolphins have been recovered from beaches between New York and North Carolina—10 times the number usually recovered at this time of year.
In early August, the large number of strandings prompted the National Oceanic and Atmospheric Administration (NOAA) to declare an Unusual Mortality Event. The declaration freed up federal funding to assist NOAA’s Marine Mammal Health and Stranding Response Program to retrieve and assess the mammals’ remains. The results of their investigation point to a type of morbillivirus as the cause of the die-off—a group that includes viruses that cause measles in humans and distemper in dogs.
The team’s detective work combined traditional techniques that examined tissues from dead animals’ lungs, brains, and lymph systems with molecular techniques to probe for the presence of the virus. So far, researchers have examined 33 dolphins; 32 have tested positive for morbillivirus. Genetic sequencing has confirmed that 11 carry the type of morbillivirus that infects only dolphins, porpoises, and whales.