Swine flu

An outbreak caused by a novel strain of H1N1 influenza, commonly called "swine flu", began in Mexico in March 2009 and spread rapidly to many other countries. The virus contains a unique combination of swine, avian, and human influenza gene segments that had not been previously observed. Initial reports from Mexico indicated a high fatality rate in previously healthy young adults and older children, raising concerns that a worldwide pandemic might occur, similar to 1918. However, subsequent data from Mexico, as well as experience from other countries, indicated the H1N1 strain from 2009 is not nearly as lethal as some people initially feared. Preliminary data indicate that up to one-third of those greater than 60 years of age have antibodies against the novel H1N1 virus, whereas protective antibodies are found much less frequently in children and younger adults (see MMWR). This is consistent with the clinical experience, which indicates that the most severe cases have occurred in those younger than age 60.

On August 10, 2010, the World Health Organization declared the H1N1 influenza pandemic was over, saying worldwide flu activity had returned to typical seasonal patterns and many people had immunity to the virus. However, in April 2011, the Pan-American Health Organization issued an alert that there were significant outbreaks of H1N1 influenza in the Americas, though geographically limited. The PAHO reported outbreaks in Ecuador (January 2011), Mexico and Venezuela (March 2011), and the Dominican Republic (April 2011). Sporadic detections were also reported from Cuba, Colombia, Honduras, Jamaica and El Salvador.

To protect yourself from H1N1 influenza, wash your hands regularly and avoid close contact with anyone who is coughing or sneezing. Routine use of face masks is not recommended. The symptoms of H1N1 influenza include fever, cough, sore throat, body aches, headache, chills and fatigue, similar to seasonal influenza. Any traveler who develops flu-like symptoms after travel to a country which has reported H1N1 influenza should immediately seek medical attention. Empiric treatment with oseltamivir (Tamiflu) and zanamivir (Relenza) should be considered for suspected cases, though a small number of Tamiflu-resistant isolates have been described. The virus is resistant to amantadine and rimantadine. Vaccination against novel H1N1 influenza is recommended for everyone, except those allergic to the vaccine or one of its components. For further information on novel H1N1 influenza (swine flu), go to the World Health Organization and the Centers for Disease Control.