(UPI) -- Hundreds of dead bottleneck dolphins, killed in a measles-like outbreak, have washed up along the U.S. Atlantic coast since July.
The National Oceanic and Atmospheric Administration (NOAA) said that a total of 753 dolphins have washed up between New York and Florida in the last four months. This is 10 times more than the number of dolphins usually found dead along the coast.
"Historic averages for this same time frame, same geographic area is only 74, so you get an idea of the scope," said Teri Rowles, coordinator of NOAA’s Marine Mammal Health and Stranding Response Program, which already classified the outbreak as an Unusual Mortality Event.
The mobillivirus has been identified as the cause for the deaths, and is not limited to dolphins. A handful of humpback whales and pygmy sperm whales have also tested positive for the virus, but due to decomposition the cause of death could not be ascertained.
Five percent of the dolphins were found alive on the shore but died shortly thereafter. With no way to vaccinate a wild population, all researchers can do is collect the carcasses and study them.
The virus cannot harm humans, however sick dolphins are carriers of other bacteria and infections which can affect humans. People have bee asked to stay away from stranded animals on beaches.
The death toll is also higher than the more than 740 strandings in the last major Atlantic morbillivirus outbreak in 1987-88. Immunity to the virus has been decreasing among bottleneck populations, particularly in younger animals.
"So we know we had a susceptible population, but just being susceptible alone is not how the outbreaks go," said Rowles. "We are trying to understand where this virus came from and how it got into the population in which it is now circulating."