National Geographic News
A pair of Bottlenose Dolphins surface to breathe on a calm summer day.

Two bottlenose dolphins surface to breathe.

Photograph by Jason Edwards, National Geographic Stock

Jane J. Lee

National Geographic

Published August 27, 2013

The hundreds of bottlenose dolphin deaths along the U.S. East Coast are likely due to a disease outbreak called cetacean morbillivirus, the U.S. National Oceanic and Atmospheric Administration (NOAA) Fisheries announced today.

As of August 26, 333 dolphins have washed up dead or dying on beaches from New York to North Carolina, Teri Rowles, a coordinator with NOAA Fisheries marine mammal health and stranding response program, said at a press conference. Virginia seems to be a "hot zone," reporting 174 dolphin strandings as of Monday. (Take a look at the numbers, state by state.)

Cetacean morbillivirus is in the same family as the virus that causes measles in people. But this group of viruses tends not to jump from species to species, said Jerry Saliki, a virologist at the University of Georgia who has been conducting laboratory analyses of samples from the stranded dolphins.

Even so, NOAA officials are warning the public not to approach stranded dolphins as they could have secondary bacterial or fungal infections that could pose a risk to people, especially those with open wounds. (Related:"New Diseases, Toxins Harming Marine Life.")

"Along the Atlantic seaboard, this [outbreak] is extraordinary," Rowles said. The last morbillivirus outbreak in the region occurred from June 1987 to May 1988, and resulted in the deaths of at least 900 bottlenose dolphins. (Related:"U.S. Dolphin Deaths Rise to 300; Cause Still a Mystery.")

Officials are unsure of how long the current outbreak will last. "Typically, outbreaks will last as long as there are susceptible animals," Rowles said.

But if it plays out like the 1987-1988 outbreak, "we're looking at mortality being higher and morbillivirus traveling southwards and continuing until May 2014," she added.

Right now, experts think this current outbreak is probably due to a dip in "herd immunity."

Dolphins that survived the 1987-88 morbillivirus outbreak carry antibodies to the virus which protects them against it. These resistant individuals also help protect new or young dolphins without natural immunity, since these unprotected individuals have less chance of contracting the virus.

But eventually, those virus-resistant dolphins die or leave, and "then the whole population becomes susceptible," said Saliki.

Studies have shown that dolphins younger than 26 years have limited to no immunity to this virus, said Rowles. "So if this virus is introduced, they don't have the initial antibodies to protect them from significant illness."

Rowles added that environmental factors, such as heavy metal pollution and sea surface temperature changes, could also play a role in the current outbreak. But researchers are still gathering data to answer these questions.

If you see a stranded dolphin, contact the following hotlines:

In the northeastern U.S.: 1-866-755-6622

In the southeastern U.S.: 1-877-942-5343

Follow Jane J. Lee on Twitter.

Solon Lechonitis
Solon Lechonitis

Very sad to read the disease of These wonderful animals the dplphins nad whales.Solon

Cody Maitland
Cody Maitland

I love dolphins..!!!!!!!!!!!!!!! I can't believe somebody could do this.

Irene Alexander
Irene Alexander

How on earth are we meant to help those already infected? That's the depressing part.

Patienze McIntyre
Patienze McIntyre

To hear about these dolphins make me sad to know they may become extinct

Peace Seeker
Peace Seeker

'Plastic Shores' is a documentary about the effects of plastic waste on our marine ecosystem. In the year 2010, global plastic production exceeded 260 million tonnes. A third of this was used in disposable packaging, thus resulting in an incredible 6 million tonnes of debris entering our oceans every year.

'Plastic Shores' explores the journey of plastics once they have entered the water: what affects they have on aquatic species and human health, how they break down, and how they travel on the ocean's currents. Travelling from the International Marine Debris Conference in Hawai'i to the polluted Blue Flag beaches of Cornwall, the film reveals just how bad the problem is through a wide range of interviews with well-known figures in the field such as Congressman Sam Farr and Roz Savage.

The second half of the film then focusses on what we can do, as individuals, to mitigate our use of disposable plastics through the 3R concept (reducing, reusing and recycling).

Elisabeth G.
Elisabeth G.

this is just so sad i dont know what to say.

m s
m s

This has been going on since 2010. Scientists might not be able to put two and two together but the rest of us can. All it would take is for someone to look at the migration of these dolphins that end up on the east coast to see if their migration passes thru the gulf. If it does then there's definitely a connection both to the oil and to the corexit, the chemical used to clean up the oil that's highly toxic even to the men and women who dispersed it while in hazmat suits. If these dolphins do cross the gulf then that means they are being affected by this chemical and it's reducing their immune response much like the bees in canada when exposed to the see pesticides.

Irene Alexander
Irene Alexander

@m s they use one evil to get rid of's absolutely disgusting.


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