The dolphin morbillivirus has killed more than 750 dolphins since June, when it first emerged off beaches from Long Island to Virginia.
The southward migration of the marine mammals since then has spread the disease all the way to Florida.
Resident Florida bottlenose dolphins are now at risk of catching the virus, which spreads through close contact.
And the U.S. environment agency NOAA says the virus is also the cause of death of two pygmy sperm whales and three humpback whales found dead or dying along the Atlantic coast.
The outbreak of the virus is the worst on record and has killed more than 10 times the number of dolphins that would normally turn up dead along the Atlantic seaboard during the period.
And wildlife officials say that if the current outbreak is anything like the previous record 1987-1988 die-off, it’s only halfway through, and fatalities will go much higher.
Photo: Virginia Aquarium and Marine Science Center