Last week, researchers from the Centers for Disease Control and Prevention (CDC) and state and local public health agencies published information on the first 642 cases of H1N1 virus (swine flu) in the United States. Their findings were published online May 7, 2009 in the New England Journal of Medicine.

From April 15, 2009 through May 5, 2009, a total of 642 laboratory-confirmed cases of H1N1 infection were identified in 41 states across the country. The affected patients ranged in age from 3 months to 81 years, and 60% of the patients were 18 years old or younger. Approximately 18% had a history a recent travel to Mexico and 16% were identified from school outbreaks. While the most common presenting symptoms were fever, cough, and sore throat, one-quarter of the patients had diarrhea and another quarter had vomiting. These gastrointestinal symptoms are not typical for seasonal influenza, so patients and physicians should be aware of these possible signs of infection.

Most of the confirmed cases of H1N1 infection in the United States have been self-limited, uncomplicated respiratory illnesses associated with fever. However, hospitalizations, admission to the intensive care unit, respiratory failure, and death have all been reported. The researchers note that the identification of H1N1 infection in geographically dispersed countries and across continents demonstrates how easily the infection can be spread by travel and community networks. They suspect that the number of confirmed cases likely underestimates the true number of cases that have occurred and that, as surveillance for H1N1 increases, additional cases will be identified.

Source:

N Engl J Med published online May 7, 2009.