A measles-like virus has been sweeping through bottlenose dolphins along the Eastern Seaboard. Since July, more than 330 dolphins have washed up dead on shore between North Carolina and New York, and many more are likely infected.
In August, the National Oceanic and Atmospheric Administration – or NOAA – declared an Unusual Mortality Event, which resulted in federal funding to collect and analyze the dolphins’ remains.
NOAA researchers examined tissue from the dolphins’ lungs, brains and lymph systems and determined that the culprit was a morbillivirus – the same type of virus that causes measles in humans. Thirty-two of 33 dolphins examined tested positive for the virus.
Sadly, unlike with humans, there is no way to protect against or treat the illness in dolphins. This year’s outbreak is the largest since 1987, when the morbilivirus killed more than 700 dolphins. Dolphins that were alive for the 1987 outbreak may have developed immunity that protected them this year. But all those born since 1987 were likely susceptible.
Experts theorize that the virus may take hold of a population once it reaches a critical “tipping point,” where enough animals are susceptible to support its spread. They predict the virus will recede once the amount of susceptible individuals decreases.
NOAA is also investigating whether high levels of PCBs, which have been reported in some areas of the Eastern coastline and which suppress mammals’ immune system, are contributing to the severity of the outbreak.
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Web Links
http://news.sciencemag.org/health/2013/08/measleslike-virus-likely-culprit-u.s.-dolphin-die
Photo, taken on November 1, 2009, courtesy of Jason Pratt via Flickr.
Earth Wise is a production of WAMC Northeast Public Radio. Support for Earth Wise comes from the Cary Institute of Ecosystem Studies in Millbrook, NY.