HARRISBURG, Pa. — State officials say three Pennsylvania children who attended an agricultural fair in southwestern Pennsylvania have contracted a new strain of influenza containing the H1N1 virus. (Snip) all three children attended the Washington County Agricultural Fair the week of Aug. 13 to Aug. 20.
(Snip) one child has recovered, while two confirmed ill over the weekend are recuperating. The cases are similar to past human infections with swine-origin H3N2 viruses. But the new strain also contains the H1N1 virus linked to the 2009 flu pandemic.

The state is investigating how the illness was transmitted. But health department spokeswoman Christine Cronkright says there doesn’t appear to be any human-to-human contact.

Anyone who attended the Washington County Fair and has flu-like symptoms should contact their medical provider or call 1-877-PA-HEALTH.


Washington Fair trH3N2 Cluster Signals Human Transmission
Recombinomics Commentary
The Pennsylvania departments of Health and Agriculture today announced three cases of a novel influenza A virus have been identified, and are now linked to an agricultural fair in southwestern Pennsylvania. 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 of the H1N1 virus.

(Snip) Department of Health press release describe two additional confirmed trH3N2 cases at the Washington County Fair. Like the earlier case in Indiana, A/Indiana/08/2011, and the previously reported case from Schuykill County, PA who attended the above fair, the two new cases had the H1N1 M gene segment, which is linked to aerosol spread in a guinea pig model of human influenza transmission.

These cases increase the Pennsylvania total of confirmed cases to five, including three 2011 cases with the M gene segment. The three confirmed cases represents the largest number of confirmed trH3N2 cases at a given location, and the investigation is still ongoing.

The press release does not clarify the severity of the infection in the two most recent cases, who may have been ill for nore than two weeks. Hospitalization was not addressed in the press release, but the four cases with H1N1 M1 appear to be serious enough to warrant emergency department visits.

It is likely that these three cases represent unsubtypable trH3N2 which is not recognized by the human H3 serotyping reagents, suggesting existing immunity to seasonal H3N2 will provide limited protection. Additional cases are under investigation, but this cluster strongly supports human to human transmission of a novel trH3N2 with a pandemic H1N1 M gene segment. The unsubtypable cases will be more easily identified by state labs, and an explosion of confirmed cases is expected. (Snip)