It's too early to tell if the traditional winter flu outbreak will be uneventful or will send Americans scurrying for cover. But federal health officials already have their eyes peeled on what may be the next potential menace: a virus transmitted from pigs to humans.
The virus, dubbed influenza A H3N2 variant, is not a major threat to the public right now, although it had a pretty good run over the summer. Experts at the Centers for Disease Control and Prevention recently asked state and county public health officers nationwide to step up their efforts to swiftly identify and investigate potential H3N2 cases, a move that's necessary to help federal authorities evaluate the extent of the outbreak and possible human-to-human transmission.
Persistent watchingdogging like this is a common m.o. among health officials and is essential to making sure a small outbreak doesn't morph into a major flu pandemic.
Here are the facts so far. Since July 12, 305 infections have been reported in 10 states: Hawaii, Illinois, Indiana, Maryland, Michigan, Minnesota, Ohio, Pennsylvania, West Virginia and Wisconsin. Sixteen people have been hospitalized and there has been one death linked to the infection. In the majority of cases, people had prolonged exposure to swine, such as by caring for farm animals. However, CDC officials say there are "likely" cases where the virus was passed from one infected person to another.
There is still no evidence of ongoing transmission from human to human—the kind of flu activity where a sneeze infects three other people and suddenly an illness has snaked throughout a community. But that's not to say that flu experts aren't watching H3N2 warily, Dr. Gregory A. Poland, director of translational immunovirology and biodefense at the Mayo Clinic and Foundation in Rochester, Minn., told TakePart.
"I worry about this a lot," says Poland, also a spokesperson on flu for the Infectious Diseases Society of America. "There have only been—documented—a few hundred cases so far. But, in Ohio, there were 10 hospitalizations and one death. This is not a trivial development. There is close, careful surveillance."
CDC officials noted in the recent report that five of the hospitalized patients had no other serious medical conditions, "highlighting the fact that H3N2v virus infection can cause illness resulting in hospitalization, even in otherwise healthy persons."
Flu viruses are transmitted easily among pigs, but they can spread to people through close contact. Swine flu viruses are not transmitted by eating pork or foods derived from pork, health officials say. According to Poland, the human H3N2 virus acquired the M gene from the 2009 H1N1 virus to produce a problematic new virus. The M gene is known to play a role in flu infection, but it's still unclear how the acquisition of this gene will affect the swine-origin influenza A H3N2 virus.
"The question is how transmissible this will be?" he says.
This year's flu vaccine has a component that covers H3N2 strains but not this particular one, Tom Skinner, a senior spokesman for the CDC told TakePart. "A vaccine that included H3N2v would be needed if we saw widespread and sustained human to human transmission," he says. "We are not seeing that with this virus."
Taking the usual precautions—washing hands thoroughly and avoiding other sick people—will help protect most people from H3N2v. Staying away from pigs is especially important. In particular, children younger than age 5, adults older than 65 and people with health problems should avoid swine on farms or at state fairs this fall.
"This virus is a particular concern for the vulnerable groups," Poland says. "If you have a young child, are an older person, are pregnant, or have chronic medical conditions, don't go to these state fairs."
The onus, for now, is on doctors and public health officials to keep an accurate count of H3N2v cases. Rapid flu tests commonly used in doctor's offices may not detect this particular strain, however, and testing should be conducted at state public health labs.
The public, meanwhile, shouldn't assume that this season will be a repeat of last year's mild one.
"One cannot predict based on last year what will happen this year," Poland says. "You can't even predict today what will happen in December with influenza. The only truth about this virus is that it's unpredictable."
If you are around pigs, either at farms, petting zoos or state fairs, follow these precautions from the CDC:Don't take food or drink into pig areas. Don't take toys, pacifiers, cups, baby strollers and other baby items into pig areas. Avoid close contact with pigs that look or act ill. Take precautions if you have to be around a pig known to be ill. Wear gloves, masks and protective clothing. Wash your hands before and after exposure to pigs. If you have a pig that looks ill, call the veterinarian. Avoid contact with pigs if you have flulike symptoms. Wait seven days after the illness started or 24 hours after your fever is gone (without the use of fever-reducing medication).
Do you think the country is equipped to handle a flu pandemic? Let us know in the comments.
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Shari Roan is an award-winning health writer based in Southern California. She is the author of three books on health and science subjects.
- Public Health
- Infectious Diseases