Seasonal (or common) influenza is a respiratory illness, caused by influenza Type A and Type B viruses. It occurs every year on a seasonal basis and can spread from person to person. Because prevalent influenza viruses expected to be responsible for the annual seasonal influenza outbreaks change frequently, seasonal vaccines have to be reformulated each year. There may be limited immunity carried over from previous influenza infections to limit the effects of seasonal influenza, but annual vaccination is generally recommended to prevent seasonal influenza annually.
Avian influenza (or bird flu) is caused only by influenza Type A viruses. These viruses occur naturally among wild birds. Low pathogenic (i.e., low mortality) avian influenza is common in birds and causes few signs of illness. A highly pathogenic (i.e., higher mortality) avian influenza (H5N1) virus is deadly to domestic birds. It rarely transmits from birds to humans, but when a person is infected, the illness is often fatal. Humans have virtually no immunity to highly pathogenic H5N1 avian influenza.
Pandemic influenza is any human influenza caused by a mutated influenza Type A virus for which there is little natural immunity and which spreads easily from human to human across a wide area of the world. In 2009, the H1N1 novel influenza (so-called "swine flu") was declared a pandemic by world health organizations, and we are now in the post-pandemic period. No pandemic form of the H5N1 virus has emerged, but scientists are concerned that a strain of avian influenza with a high mortality rate could evolve into a virus that is easily and repeatedly spread from human to human, causing a severe pandemic.
You can find information about H5N1 avian influenza, and pandemics in general, at:
You can follow the advice that the U.S. Department of Health and Human Services has developed to guard against infection during a pandemic. It includes simple techniques such as:
If you need to enter crowded areas, you should consider using a face mask for protection against others who are coughing and to limit your likelihood of coughing on others. However, there are no definitive studies regarding the effectiveness of face masks in preventing the transmission of the influenza virus. For more complete information, please visit the U.S. Department of Health and Human Services (HHS) flu website.
If you work or study overseas, you should contact your sponsors for information about their pandemic readiness plan. Ask if they will let you work from home (telework, etc.) in the event of a severe pandemic. Will they provide you with antiviral medications, medical care, and/or a pandemic vaccine, if available? Have they stored 12 weeks of food and drinkable water for your use in a pandemic, or do you need to buy and store these provisions yourself?
Both of these medications are approved for treating (and, in limited circumstances, preventing) acute uncomplicated seasonal influenza. However, we don't know how effective antiviral medications such as Tamiflu® (oseltamivir) and Relenza® (zanamivir) would be in treating H5N1 in a pandemic situation. Each drug has different approved doses and dosing instructions for children. Consult with your healthcare provider and read the instructions carefully before use. Evidence indicates that the sooner you take these antivirals, the better the outcome. You should be aware that antiviral drugs are not a substitute for vaccines. The U.S Department of Health and Human Services/Food and Drug Administration's (HHS/FDA) website has more information on antiviral medications.
If you are overseas, you should find out if antiviral medications are available where you live and whether you need a prescription. If adequate medical treatment or antiviral medications such as Tamiflu® or Relenza® are not readily available at your overseas location or travel destination(s), talk to your doctor about buying a supply before you travel overseas. You can buy antiviral medications in the United States with a prescription from your doctor or healthcare provider. Due to legal restrictions, U.S. embassies and consulates cannot provide private U.S. citizens with medications, supplies, or medical treatment. The CDC has information on travel related diseases. Remember, don't take expired medications because they can be dangerous.
It is important for you to consider the local availability of medical diagnosis and treatment, including hospital care and medication, in the event of a pandemic. The internet may provide useful information. For a current list of doctors/hospitals in the country to which you are traveling, you can access the U.S. Department of State's list of embassies and consulates. You will find a list of medical practitioners either in the Consular Services or American Citizen Services section of the embassy web site.
The WHO and CDC have identified several chronic medical conditions that may cause a higher risk of suffering complications from influenza. If you have one of these conditions, you should consider returning to the United States early at the onset of a severe pandemic or postponing your travel. Those at high risk may include pregnant women; adults and children who have chronic pulmonary (including asthma), cardiovascular (except hypertension), renal, hepatic, hematological, or metabolic disorders (including diabetes mellitus); adults and children who have suppressed immune systems (caused by medication or by HIV); and adults and children who have any neurological condition (e.g., cognitive dysfunction, spinal cord injuries, seizure, or other neuromuscular disorders) that can compromise respiratory function. In the event of an actual severe pandemic, additional groups might be at particular risk of becoming ill.
You should check the HHS/CDC and WHO websites for the latest information. You can obtain additional country information from the U.S. Department of State's country information and Embassy and Consulate web pages. You may also call the U.S. Department of State's toll-free number, 1-888-407-4747, or if calling from overseas, 1-202-501-4444, from 8 a.m to 5 p.m. EST.
If a severe pandemic occurs, the U.S. Government may, depending on conditions, encourage its non-emergency employees and all dependents to return to the United States via commercial means, if available. If it does so, it will also recommend that private U.S. citizens consider departing via commercial means, as well. A variety of factors may lead U.S. citizens to remain abroad, including a personal family situation or the possibility of contracting influenza during travel. A pandemic could result in quarantines, border closures, or a lack of equipment or crews, and some people may be forced to remain abroad for these reasons.
Evacuations (including non-combatant evacuation operations (NEOs) supported by the Department of Defense) will be considered only if there is a breakdown in civil order that cannot be contained by local authorities and that further threatens the lives of U.S. citizens in a particular country. Even then, such evacuation operations may not be possible or advisable based on other concerns. Note that, if the U.S. Government does coordinate an evacuation operation, private U.S. citizens may be required to find their own transportation to the departure point, and will be required to reimburse the USG for all costs of their evacuation.
You should make sure, in advance, that you have access to adequate supplies of food, drinkable water, and medications in case you are unable to leave a foreign country during a pandemic. Refer to the U.S. Department of State's Options during a Pandemic page and to the U.S. Department of Health and Human Services (HHS) flu website for more planning information.
In the event of a pandemic, monitor the HHS/CDC and WHO websites for the latest information. You can get additional information about the country where you are located from the U.S. Department of State's country information and Embassy and Consulate web pages. You may also call the U.S. Department of State's toll-free number, 1-888-407-4747, or, if calling from overseas, 1-202-501-4444, from 8 a.m. to 5 p.m. EST weekdays.
If a pandemic causes border closures, quarantines, or other temporary disruptions in commercial transportation, your only option might be to remain in the foreign country to wait out the pandemic. At that point, U.S. Government assistance to you might be limited to emergency services from the nearest U.S. embassy or consulate. Examples include communicating urgent messages to/from family and friends, monitoring quarantine/detention conditions as permitted by local health authorities, arranging for transfers of funds from your family or granting temporary subsistence loans, and providing information regarding the availability of local medical care (to be paid for by the individual). Some of these services may not be immediately available during a severe pandemic. Due to legal restrictions, the U.S. Department of State cannot provide private U.S. citizens with food, water, medications, supplies, or medical treatment in the event of a pandemic.
The U.S. Department of State cannot demand your immediate release if you are detained or quarantined abroad in accordance with local public health and legal authorities. Every effort will be made to assist you, but U.S. Government offices overseas may limit operations because of reduced staffing or other conditions. Once the pandemic subsides and travel resumes, the U.S. Department of State can once again provide full consular services to you, including routine repatriation assistance.
A vaccine for humans that effectively prevents infection with the avian influenza Type A (H5N1) virus is not yet available. The avian influenza Type A (H5N1) virus is continually evolving, so a specific vaccine cannot be developed until a pandemic begins. Experts anticipate a four-to-six month lag between identification of the pandemic influenza virus and development and distribution of an effective vaccine. Presently, this virus cannot easily pass from human to human in a sustainable manner, but we do not know how the virus might evolve.
You should avoid contact with live birds including: chickens, ducks, turkeys, and geese; bird products including their feces and feathers; live bird markets; wet markets; and bird pens, if at all possible. Teach these precautions to your children; supervise small children to protect them from these potential threats. Do not purchase or agree to adopt pet birds from an area in which avian influenza has been reported. Avoid poultry products from areas with avian influenza-infected birds. Do not transport live poultry, even if the birds appear to be healthy, or dead poultry. Importing birds or unprocessed bird products into the United States from areas affected by H5N1 is not permitted.
Even if you assume that the poultry is safe to eat, cook all poultry products thoroughly, including eggs and poultry blood. Egg yolks should be firm, not runny. Cook poultry to an internal temperature of 165 degrees Fahrenheit (74 degrees Celsius) to kill any viruses or bacteria. Avoid cross-contamination with other foods by keeping kitchen utensils and surfaces that are exposed to raw poultry separate from utensils and surfaces used for cooked poultry products and other foods. Wash your hands with soap and water after any poultry contact. For more information on food handling and safety, please visit the U.S. Department of Agriculture (USDA) web site.
Sanitation professionals, healthcare workers, and others who must travel to areas infected by avian influenza and work directly with infected birds, poultry, and humans should follow approved precautions for reducing the risk for infection with H5N1 virus. See the HHS/CDC guidance for professionals.
There have been reports of H5N1 infection in domestic cats, dogs, pigs, tigers, leopards, ferrets, and stone martens, among other animals. Domestic cats and dogs are believed to have been infected by eating raw, H5N1-infected birds. Although no human cases of avian influenza Type A have been associated with contact with infected cats, you should keep your cats inside if there has been a verified outbreak of H5N1 in your area. In addition, avoid contact with stray cats and inform your local veterinarian if your cat becomes sick after having had contact with birds. You should always follow strict hygiene rules when disposing of animal waste or caring for your pets.
For more information about H5N1 infection in pets, see the HHS/CDC web site.