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Virus on the high seas: Human pandemic strain found in California marine mammals

Elephant seals on a beach along California’s central coast in San Simeon Calif. Researchers have detected swine flu in elephant seals off the Central California coast, saying it was the first time a human pandemic strain has been found in marine mammals.
Elephant seals on a beach along California’s central coast in San Simeon Calif. Researchers have detected swine flu in elephant seals off the Central California coast, saying it was the first time a human pandemic strain has been found in marine mammals.
Reed Saxon/AP Photo

For the first time, a human pandemic virus strain has been found in marine mammals.

The Associated Press reports that H1N1 — the devastating "swine flu" virus that killed as many as half a million people during a 2009 global outbreak — has been found in elephant seals off the central coast of California.

A University of California, Davis study published this week found the seals contracted the H1N1 virus in 2010, but show no sign of illness, reported the Contra Costa Times.

It's not the first time a marine mammal has been found carrying a human strain, UC Davis professor Tracey Goldstein told the newspaper, but it is the first time researchers found a human pandemic strain. 

Goldstein said the influenza virus commonly crosses species barriers and that the presence of H1N1 in seals is not a cause for alarm. But it's a good reminder, she said, for "people who work with animals to make sure that they protect themselves."

Researchers say it's unlikely that the seals contracted the virus from direct contact with humans. Data suggests the animals were exposed at sea or coming near the shore — it's possible that seabirds may have passed on the virus.

UC Davis wildlife biologists swabbed the noses of 72 elephant seals over the course of two years at Ano Nuevo State Reserve in San Mateo County and Piedras Blancas in San Simeon. The animals were sampled before and after their annual spring foraging trip to Alaskan waters.

The animals tested clean before departure, but two came back bearing the virus in 2010, the newspaper said. A year later, 16 elephant seal pups had blood tests showing they had been exposed to the virus.

What is a pandemic?

According to OSHA:

A pandemic is a global disease outbreak. A flu pandemic occurs when a new influenza virus emerges for which people have little or no immunity, and for which there is no vaccine. The disease spreads easily person-to-person, causes serious illness, and can sweep across the country and around the world in a very short time.

It is difficult to predict when the next influenza pandemic will occur or how severe it will be. Wherever and whenever a pandemic starts, everyone around the world is at risk. Countries might, through measures such as border closures and travel restrictions, delay arrival of the virus, but they cannot stop it.

California's relationship with H1N1

According to the CDC:

Infection with this new influenza A virus (then referred to as ‘swine origin influenza A virus’) was first detected in a 10-year-old patient in California on April 15, 2009, who was tested for influenza as part of a clinical study...Two days later, CDC laboratory testing confirmed a second infection with this virus in another patient, an 8-year-old living in California about 130 miles away from the first patient who was tested as part of an influenza surveillance project.

There was no known connection between the two patients. Laboratory analysis at CDC determined that the viruses obtained from these two patients were very similar to each other, and different from any other influenza viruses previously seen either in humans or animals.

Testing showed that these two viruses were resistant to the two antiviral drugs amantadine and rimantadine, but susceptible to the antiviral drugs oseltamivir and zanamivir. CDC began an immediate investigation into the situation in coordination with state and local animal and human health officials in California.

What's the next possible lurking pandemic?

Science Daily reports on a new MIT study that investigates potential flu pandemics circulating in pig and birds that could pose a significant threat to humans if they jump the species barrier.

In the summer of 1968, a new strain of influenza appeared in Hong Kong. This strain, known as H3N2, spread around the globe and eventually killed an estimated 1 million people.

A new study from MIT reveals that there are many strains of H3N2 circulating in birds and pigs that are genetically similar to the 1968 strain and have the potential to generate a pandemic if they leap to humans.

The researchers, led by Ram Sasisekharan, the Alfred H. Caspary Professor of Biological Engineering at MIT, also found that current flu vaccines might not offer protection against these strains.

The study appears in the May 10 issue of the journal Scientific Reports noting a number of potentially dangerous viral strains that public health agencies should be on the lookout for.