Fair warning: don't pet pigs, CDC says
MedWire News: If your patients are going to a country fair or farm, tell them not to pet the pigs, the Centers for Disease Control and Prevention (CDC) advises.
As of August 10, there were a total of 153 cases of human infection with influenza A (H3N2) variant virus (H3N2v), more commonly known as "swine flu," report Shawn Richards (Indiana State Department of Health) and co-authors in Morbidity and Mortality Weekly Report.
The virus appears to be transmitted to people who touch or pet infected pigs. More than 90% of the reported infections were in children younger than 18 (median age 7 years). Most cases are mild, self-limited, and resolve without further treatment. There have been no reported deaths, although two patients were hospitalized; both have recovered and were discharged, the CDC reports.
The patients, primarily from Illinois, Indiana, and Ohio, had all reported direct or indirect contact with pigs, mostly at country fairs.
"At this point, there's no evidence of sustained efficient human-to-human spread in the community," said Joseph Brese from the CDC in a telebriefing. "Our seasonal influenza systems are active and have not shown any sign of increase in influenza activity. This is not a pandemic situation. But of course, CDC is continuing to monitor the situation closely, and we'll provide updates frequently. Right now, a large number of agricultural fairs are ongoing around the country and direct exposure of people to infected pigs has been the primary cause of infections, from investigations conducted so far this year."
The outbreak was first reported in July, at the beginning of agricultural fair season. The viral strain is similar to that identified from July 2011 through April 2012. All of the viruses identified thus far carry the "M" gene from the pandemic 2009 influenza A (H1N1) virus.
The CDC advises that people in direct contact with pigs practice good hand hygiene and avoid pigs that appear to be sick. People at high risk for complications from the flu ‑ such as young children, the elderly, and those who are immunocompromised ‑ should avoid contact with pigs altogether.
"Clinicians should consider antiviral treatment with oral oseltamivir or inhaled zanamivir in patients with suspected or confirmed H3N2v infection. Antiviral treatment is most effective when started as soon as possible after influenza illness onset," MMWR editors note.
By Neil Osterweil, MedWire reporter