(Updated October 2007)

During 2005, outbreaks of H5N1 among poultry were confirmed in Cambodia, China, Indonesia, Thailand, Vietnam, Russia, and Kazakhstan; poultry outbreaks were also reported in Malaysia and Laos during 2004. Since January 2004, 331 human cases of avian influenza A (H5N1) have been reported to date: one hundred in Vietnam, twenty-five in Thailand, seven in Cambodia, and 109 in Indonesia, resulting in 202 deaths worldwide, none of which were in the US. CDC remains in communication with WHO and continues to closely monitor the H5N1 situation in countries reporting human cases and animal outbreaks. We remain in a Phase 3 level of worldwide alert in which there are no (or very rare) documented cases of human to human transmission.

Most cases of H5N1 infection in humans are thought to have occurred from direct contact with infected poultry in the affected countries. Therefore, when possible, care should be taken to avoid contact with live, well-appearing, sick, or dead poultry and with any surfaces that may have been contaminated by poultry or their feces or secretions. Transmission of H5N1 viruses to two persons through consumption of uncooked duck blood may also have occurred in Vietnam in 2005. Therefore, uncooked poultry or poultry products, including blood, should not be consumed.

The threat of novel influenza subtypes such as influenza A (H5N1) will be greatly increased if the virus gains the ability to spread from one human to another in a sustained fashion. Such transmission has not yet been observed; however, a few cases of limited person-to-person spread of H5N1 viruses may have occurred.

A vaccine to protect humans against avian influenza A (H5N1) is not yet available, but one is undergoing human clinical trials.

CDC has not recommended that the general public avoid travel to any of the countries affected by H5N1. Persons visiting areas with reports of outbreaks of H5N1 among poultry or of human H5N1 cases can reduce their risk of infection by observing the following measures:

Before Any International Travel to an Area Affected by H5N1 Avian Influenza

  • Visit CDC's Travelers' Health webpage on Southeast Asia to educate yourself and others who may be traveling with you about any disease risks and CDC health recommendations for international travel in areas you plan to visit. For a list of affected areas and other information about avian influenza, see these webpages provided by the Centers for Disease Control and Prevention and the Department of Health and Human Services.
  • Be sure you are up to date with all your vaccinations, and see your doctor or health-care provider, ideally four to six weeks before travel, to get any additional vaccination medications or information you may need.
  • Assemble a travel health kit containing basic first aid and medical supplies. Be sure to include a thermometer and alcohol-based hand gel for hand hygiene. See the Travelers Health Kit page in Health Information for International Travel for other suggested items.
  • Identify in-country health-care resources in advance of your trip.
  • Check your health insurance plan or get additional insurance that covers medical evacuation in case you become sick. Information about medical evacuation services is provided on the U.S. Department of State webpage Medical Information for Americans Traveling Abroad.

During Travel to an Affected Area

  • Avoid all direct contact with poultry, including touching well-appearing, sick, or dead chickens and ducks. Avoid places such as poultry farms and bird markets where live poultry are raised or kept, and avoid handling surfaces contaminated with poultry feces or secretions.
  • As with other infectious illnesses, one of the most important preventive practices is careful and frequent hand washing. Cleaning your hands often with soap and water removes potentially infectious material from your skin and helps prevent disease transmission. Waterless alcohol-based hand gels may be used when soap is not available and hands are not visibly soiled.
  • Influenza viruses are destroyed by heat; therefore, as a precaution, all foods from poultry, including eggs and poultry blood, should be thoroughly cooked.
  • If you become sick with symptoms such as a fever, difficulty breathing, or cough, or with any illness that requires prompt medical attention, a U.S. consular officer can assist you in locating medical services and informing your family or friends. Inform your health-care provider of any possible exposures to avian influenza. See Seeking Health Care Abroad in Health Information for International Travel for more information about what to do if you become ill while abroad. It is advisable that you defer further travel until you are free of symptoms, unless your travel is health related.

After Your Return

  • Monitor your health for ten days.
  • If you become ill with fever and develop a cough or difficulty breathing or if you develop any illness during this ten-day period, consult a health-care provider. Before you visit a health-care setting, tell the provider the following: 1) your symptoms, 2) where you traveled, and 3) if you have had direct contact with poultry. This way, he or she can be aware that you have traveled to an area reporting avian influenza.

For more information about H5N1 infections in humans, visit the World Health Organization avian influenza website, the CDC Avian Influenza website, or the Department of Health and Human Services website.