Federal officials say a virus is likely what's causing hundreds of dead bottlenose dolphins to wash ashore along the East Coast.
The National Oceanic and Atmospheric Administration says 333 dolphins have been stranded between New York and North Carolina since July 1. That's more than nine times the historical average for the region during July and August.
Earlier this month, NOAA declared an unusual mortality event to provide additional resources to study what's causing the deaths.
NOAA says the tentative cause of the deaths is the cetacean morbillivirus. Dolphins with morbillivirus typically experience skin lesions, brain infections and pneumonia. The virus killed off more than 700 dolphins in the 1980s. Using that die-off as a guide, officials say the deaths could spread southward and last through spring 2014.
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