US health officials on Friday warned the public to be careful around pigs after an outbreak of flu among visitors to county fairs.
The virus does not appear to have evolved to the point where it spreads easily among humans, but it does contain a gene from the pandemic H1N1 flu that sickened millions worldwide in 2009 and 2010.
“We are concerned that… may confer the potential for the virus to infect or spread among humans to a greater extent,” said Joseph Bresee, an influenza epidemiologist at the Centers for Disease Control and Prevention.
The virus was first detected in July 2011 and there have since been a total of 29 known cases — 16 of them in the past three weeks — in the United States.
It is a relatively mild flu — everyone recovered and only three people were hospitalized. As a result, many more cases have likely occurred without being reported to health officials.