WASHINGTON — A new flu virus thought to have originated in pigs has livestock producers on alert two years after a swine-flu pandemic caused sales to drop and disrupted U.S. pork exports.

Eleven children and one adult in five states have been infected, with three hospitalized, according to the Centers for Disease Control and Prevention (CDC) in Atlanta. At least six reported no recent exposure to pigs, suggesting "limited human-to-human transmission," according to the report.

The virus may not become as prevalent as the 2009 H1N1, which led to up to 89 million cases and 18,300 deaths in the United States in the first flu pandemic in more than 40 years, according to the CDC.

Still, livestock producers are concerned that consumers may fear they can get a potentially lethal disease from eating pork.

Flu is transmitted through droplets of infected body fluids, when people cough, sneeze or talk.

"It's always something that we need to keep an eye on, that it doesn't get more severe or spread more quickly," said Liz Wagstrom, chief veterinarian with the National Pork Producers Council. "It's very important the public understand you can't get flu from eating pork."

During the H1N1 pandemic, China and Russia closed their markets to U.S. pork, and industry revenue was estimated to have fallen by nearly $2.2 billion in the last eight months of 2009, according to the council.

The H1N1 strain contained genetic material from five flu viruses, including North American swine and bird flu and two swine-flu viruses found in Europe and Asia.

Federal agencies are not referring to the new strain as swine flu, mindful of the popular description of H1N1 that upset markets and producers.

Such illnesses contain a genetic mix of viruses seen in pigs, birds and people and get the moniker because the overall structure is the type that affects pigs.

The new virus, H3N2v, contains a gene from the 2009 variant, according to the CDC. The agency is "taking this situation very seriously" and has increased surveillance in areas where cases occurred, according to a Dec. 9 CDC report.

The strain has been detected in Indiana, Iowa, Maine, Pennsylvania and West Virginia, according to the Atlanta-based health agency.

All the people sickened have recovered, and no continuing transmission has been detected, according to the CDC.

The strain isn't too worrisome because it doesn't seem to be spreading quickly, said Peter Katona, associate clinical professor of infectious diseases at UCLA.

The reported cases have prompted "concern, but I wouldn't say it's super high," said John Treanor, chief of the infectious-disease division at the University of Rochester Medical Center in New York.