CDC: Handful of Swine Flu Cases Detected in Humans in Multiple States

— Person-to-person infection not suspected, though route of transmission unclear in one case

MedpageToday
A photo of people looking at a pig in a pen at an agricultural fair.

Five cases of human infection with flu variants normally spread only in pigs were reported to CDC in August, the agency announced in a Health Alert Network advisory on Tuesday.

Cases were detected in West Virginia, Oregon, and Ohio, and all of the individuals have since recovered.

According to the CDC, four of the infections were associated with exposure to pigs or involved individuals who had attended an agricultural fair prior to their illness. One of the individuals, however, reported no prior contact with pigs and did not attend an agricultural fair.

"No person-to-person spread associated with the five recent variant influenza virus infections has been identified," the agency stated.

Three of the cases involved the A(H3N2) variant and two involved an influenza A(H1N2) variant.The individuals suffered symptoms similar to seasonal flu, including fever, cough, pharyngitis, myalgia, and headache, and none were hospitalized, the CDC noted.

Including these new cases, 504 swine-related flu infections have been detected since the agency starting tracking the flu variants in 2005.

Medical professionals should ask patients who present with flu if they have had exposure to pigs, CDC advised: "Novel influenza A virus infections, which include those caused by variant influenza viruses, are notifiable conditions in the United States, and all confirmed cases should be reported to CDC within 24 hours."

Medical personnel are urged to take a nasopharyngeal swab or aspirate from the patient, put it in a viral transport medium, and contact the state or local health department to arrange transport and request a timely diagnosis at a state public health laboratory.

Hospitalized patients, those with severe illness, or those with a high risk of influenza complications can be treated with antiviral medication, with treatment initiation recommended within 48 hours of symptom onset, CDC said.

The agency advises that all persons at higher risk of complications of influenza avoid exposure to pigs and "swine barns" at fairs, and if avoidance is not possible, to wear a well-fitted mask that covers the nose and mouth during exposure.

The advisory noted that CDC expects that state health departments may identify more cases of infection with variant influenza viruses across the U.S., especially in late summer and fall when there are more state fairs hosting livestock, including pigs from different geographic locations.

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    Ingrid Hein is a staff writer for MedPage Today covering infectious disease. She has been a medical reporter for more than a decade. Follow