The die-off of bottlenose dolphins reported this summer from New York to the Carolinas has been getting much worse, and heading south with the annual migration.

Deaths, topping 750, and strandings are running 10 times what's considered normal, setting new records, according to NOAA, the National Oceanic and Atmospheric Administration. Experts have identified the culprit as a measles-like virus (harmless to humans) and are finding new reasons for concern: As the illness reaches Florida, it's being found in some whales, too.