H1N1 Outbreak at Air Force Academy Provides Virus Insights

Kathleen Blanchard's picture
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Scientists have gained insights about controlling H1N1 flu spread from a major outbreak of swine flu that occurred June 2009 at the U.S. Air Force Academy (USAFA). They found that the H1N1 virus persists after symptoms of swine flu have disappeared, though questions remain about how long it can spread.

The findings, published in the American Journal of Preventive Medicine, showed that one fourth of confirms H1N1 patients studied by way of nasal swabs still showed shedding of the swine flu virus seven days after onsent of symptoms. Nineteen percent reported feeling well for twenty-four hours, but still had signs of viral shedding. The results show that the virus might persist after H1N1 infected individuals return to work and have been symptom free.

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Catherine Takacs Witkop, MD, MPH, of the U.S. Air Force Academy, commented,“Characterizing virus–host interactions and the epidemiology of nH1N1 is important in both planning assumptions and in defining effective control measures. Studies of seasonal influenza suggest that viral shedding occurs for as long as 7 days after symptom onset. No similar studies on shedding of nH1N1 have been published. In addition, there are no published studies of the epidemiology of nH1N1 infection among military training populations or institutions of higher education”.

One hundred thirty four cases of H1N1 flu were confirmed at the US Air Force Academy fromJune 25 to July 24, 2009. There were thirty three suspected cases. Viable H1N1 virus was found in nasal swabs of nineteen percent of patients reporting no symptoms for at least 24 hours.

The authors says H1N1 flu “outbreak provided a unique opportunity to gain valuable information about the natural behavior of the nH1N1 virus....Novel H1N1 is now endemic in all 50 U.S. states. University- and college-based outbreaks of nH1N1 have occurred and more can be expected this fall as students gather from diverse geographic areas, reside in dorm settings and attend mass gatherings such as football games, pep rallies and student assemblies”. The findings about H1N1 flu spread are valuable for finding ways to protect public health, especially among universities needing to adopt infection control policies.

American Journal of Preventive Medicine

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