The deadliest known outbreak of a measles-like virus in bottlenose dolphins has killed a record number of the marine mammals along the U.S. Atlantic coast in 2013. Photo: WTKR

8 November 2013 (Al Jazeera) – The deadliest known outbreak of a measles-like virus in bottlenose dolphins has killed a record number of the marine mammals along the U.S. Atlantic coast in recent months, officials said Friday. A total of 753 bottlenose dolphins have washed up from New York to Florida from July 1 until Nov. 3, according to the National Oceanic and Atmospheric Administration (NOAA). The figure represents a 10-fold increase in the number of dolphins that would typically turn up dead along East Coast beaches, said Teri Rowles, program coordinator of the NOAA Fisheries Marine Mammal Health and Stranding Response Program. “Historic averages for this same time frame, same geographic area, is only 74, so you get an idea of the scope,” she told reporters. The cause of death is morbillivirus, a form of marine mammal measles that is similar to canine distemper and can cause pneumonia, suppressed immune function and brain infections that are usually fatal. The virus spreads among dolphins in close contact to one another. The death toll is also higher than the 740-plus strandings in the last major Atlantic morbillivirus outbreak in 1987-1988. And they have come in a much shorter time period, leading officials to anticipate this event could get much worse. “It is expected that the confirmed mortalities will be higher,” said Rowles.  “If this plays out similar to the ’87-88 die-offs, we are less than halfway through that time frame.” […] Among bottlenose dolphins, immunity to the virus has been decreasing, particularly in the younger animals as time has gone by since the last outbreak 25 years ago. […] In the meantime, the process of dealing with all the dead carcasses has been “overwhelming,” particularly for local recovery teams, Rowles said. The Virginia Aquarium alone has had to pick up and do necropsies on 333 animals in the space of just a few months, said Ann Pabst, co-director of the University of North Carolina Marine Mammal Stranding Program. […] While NOAA hasn’t determined a cause for the deaths, other scientists have speculated that mass die-offs like this one are becoming increasingly common as climate change causes water to warm, and human-produced pollution weakens dolphins’ immune systems. [more]

Record number of dolphins dying off East Coast in ‘measles’ outbreak