We all need to be aware of preventing the spread of Swine Flu. This includes frequent hand washing, avoiding body fluid exchanges with those who have sore throats, cough, and fever greater than 100 F. Encourage those with the above symptoms to see their physician or visit an emergency room where throat cultures and medication can be admisitered. As of April 23, 2009, five California residents (three children and two adults) have been diagnosed with swine influenza A (H1N1) virus infection. Three are residents of San Diego County and two are residents of Imperial County. There are no known links between these patients, no known common exposures and no known pig exposure. Four patients had self-limited influenza-like illness; one was patient with underlying autoimmune disease was hospitalized. All have recovered. The viruses from the five cases are closely related genetically and contain a unique combination of gene segments that have not previously been reported in the United States or elsewhere. The viruses in the first two patients are susceptible to oseltamivir and zanamivir, but resistant to amantadine and rimantadine. Antiviral susceptibility on viruses from the additional three cases is pending, but is anticipated to be the same. Swine influenza (swine flu) is an endemic respiratory disease of pigs caused by type A influenza virus, typically H1N1 and H3N2 strains. Swine flu viruses do not normally infect humans. However, sporadic human infections with swine flu do occur. Since 2005, 12 human cases of swine flu have been detected in other parts of the United States; all patients recovered. Most commonly, these cases occur in persons with direct exposure to pigs (e.g., workers in the swine industry). Although it has been documented, human-to-human transmission of swine flu is rare. However, the current situation in California suggests that human-to-human transmission may be occurring. Seasonal human influenza vaccine usually does not protect against swine influenza A H1N1 viruses, which are very different in their antigens from human H1N1 viruses. For additional information about swine flu, please see: http://www.cdph.ca.gov/HealthInfo/discond/Pages/SwineInfluenza.aspx