The Pennsylvania departments of Health and Agriculture are reporting three recent cases of a novel influenza A virus that have been linked to an agricultural fair in southwestern Pennsylvania. This is in addition to an unrelated case identified in Indiana in July.
The individual in Indiana has fully recovered as has the first individual to become ill in Pennsylvania (announced on Friday, Sept. 2). Two other individuals, confirmed ill over the Labor Day weekend in Pennsylvania, are also recovering. All three Pennsylvania cases are children who reported attending the Washington County Agricultural Fair the week of Aug. 13-20, 2011.
The cases in Pennsylvania are similar to previous, rare human infections with swine-origin H3N2 viruses, but are unique in that they contain a genetic component (the Matrix [M] gene) of the 2009 influenza A (H1N1) virus. The acquisition of the M gene in these swine-origin influenza A (H3N2) viruses indicates that they are "reassortants" because they contain genes of the swine-origin influenza A (H3N2) virus circulating in North American pigs since 1998 and the 2009 influenza A (H1N1) virus that might have been transmitted to pigs from humans during the 2009 H1N1 pandemic.
A continuing investigation, which is being jointly undertaken by the departments of Health and Agriculture, as well as the Centers for Disease Control and Prevention (CDC), has not yet uncovered how the illness was transmitted to the four individuals. However, no additional human infections with this virus have been identified to date.
The Pennsylvania Department of Health is advising anyone who attended the Washington County Fair and has flu-like symptoms to contact their local health care provider or call 1-877-PA-HEALTH. Symptoms would be similar to that of seasonal influenza, and would include fever, lethargy (extreme tiredness), lack of appetite and coughing. Other influenza symptoms may include a runny nose, sore throat, eye irritation, nausea, vomiting and diarrhea.
There has been no human to human transmission documented in any of these recent cases. Transmission of influenza from swine to humans is rare. According to the CDC, as of January 25, 2011, only 20 cases of human infection with swine origin influenza viruses (SOIV) have been reported in the United States since 2005. According to the CDC, you cannot get the flu from eating or handling pork. Pork and pork products are safe.
Sources: CDC and Pennsylvania Department of Health