(Reuters) - Swine flu is spreading in Indiana, with human cases rising tenfold in a week, state public health officials said on Wednesday, confirming 113 people are infected and saying they expect to see more.
The total confirmed cases of the Influenza A variant virus that has been transmissible from swine to humans in Indiana jumped from just 11 last week. The cases, which show symptoms of a mild seasonal flu, have been found in 18 counties across the state, state health official said.
On Monday, Indiana said it was closing the swine barn at its state fair one day early after six pigs showed elevated temperatures that could be a sign of the illness.
"It's important for folks to remember this is a mild illness with symptoms similar to what we see with seasonal flu," Dr. Gregory Larkin, the state's health commissioner, said in a statement.
Health officials have warned people to wash their hands before and after they are near swine and to not eat or drink in close proximity to pigs.
Federal officials have reported an unusually high number of human swine flu cases from a relatively new strain, influenza A variant, that came up last year.
Last week, the U.S. Centers for Disease Control and Prevention warned people to be cautious around pigs after several cases of swine flu were linked to attendance at agricultural fairs where sick pigs were present.
At the time, the CDC reported a dozen new cases of the swine flu variant had pushed the number of total cases to 29 seen since the H3N2v strain had surfaced in July 2011. Since last week, health officials in Ohio and Indiana had reported additional cases.
In Ohio, officials said they now had 30 confirmed cases, double the previous total, all in people who had direct contact with swine at fairs. No human-to-human passage of the virus has been confirmed in Ohio, officials said.
The flu in swine rarely jumps to humans, but can be spread when people are standing near an infected pig that coughs or sneezes. The flu also can be spread when a person touches an infected pig or a surface, and then their own mouth or nose.
"We believe most of these cases are still due to contact with pigs," CDC spokesman Tom Skinner said on Wednesday. "However, limited human-to-human transmission with this virus has been observed in the past and we expect that some human to human spread will be observed in these current outbreaks."