Dear Doctor Column, October 24, 2005

Avian Flu and Recommendations for Travelers

Question:

I have to travel to Thailand regularly for business. The recent news reports of a deadly bird flu spreading through Southeast Asia have me worried. What's the best way to protect myself from this disease while abroad?

Answer:

The current strain (H5N1) of avian influenza, or bird flu, first appeared in 2003 in Asia. Since then, almost 120 people have contracted the virus; all were infected through close contact with diseased birds. So far, there have been no confirmed cases of human-to-human transmission, and no infected birds have been found in America as of October 21.

The viral infection occurs naturally in birds, primarily domesticated poultry such as chickens, but also in migratory water fowl. Like all influenza viruses, avian flu is highly infectious in birds, and spreads rapidly from one diseased flock to another.

Most chickens and other domesticated fowl that contract bird flu become sick and rapidly die. But migratory birds react differently; they often survive the virus and become carriers, spreading the disease from country to country as they follow normal migration patterns.

Outbreaks of H5N1 avian flu among domestic and wild fowl have occurred in China, Cambodia, Thailand, Indonesia, Vietnam, Eastern Russia, and Kazakhstan. Migratory birds are now spreading the disease west; Turkey and Romania are the first nations on Europe's doorstep and Greece the first EU country with confirmed outbreaks in the bird population of the same deadly H5N1 strain circulating in Southeast Asia. At press time, the only countries with confirmed bird–to-human transmission and subsequent infection in humans are Cambodia, Thailand, Indonesia, and Vietnam, which has had the most cases among humans — 91 between December 2004 and October 2005.

Infectious disease experts note that it is difficult for birds to spread the virus to humans, hence the relatively small numbers of human cases since the current strain first surfaced 2 years ago, despite millions of infected fowl. The virus is spread by contact with respiratory secretions and droppings from infected birds. Because humans have no natural immunity to avian influenza, it can be lethal, and more than half the people infected with the virus have died.

Avian flu is different from strains of influenza that circulate every winter, called seasonal human influenza. Although seasonal human influenza strains change slightly each year (the reason for yearly flu vaccinations), most people have some immunity.

Recent concerns about a bird flu pandemic — or worldwide outbreak of disease — arise from fears the virus will eventually mutate so it can be transmitted from one human to another. If this occurs, international travelers will quickly spread the disease throughout the world. There is no evidence that this mutation has occurred and no way to determine when, or if, it might.

The most deadly flu pandemic occurred in 1918 and killed about 40 million people, or 1% of the world's population. Scientists recently reconstructed the 1918 flu virus and discovered it is closely related to the current bird flu strain, fueling fears that a worldwide outbreak could kill millions of people.

The speed and volume of international travel also raise concerns about rapid disease spread; in 1918, the virus took about 4 months to travel around the globe. Today, experts predict a human-to-human transmissible virus would take only weeks, or at most 2 months, to reach pandemic levels.

A vaccine would offer the best protection against bird flu. A number are in the works, but none are yet available. Vaccine development, production, and distribution is complex and time-consuming and it will likely be months before any vaccine is available.

However, travelers to Southeast Asia and other affected areas can take safety measures to reduce their chances of getting bird flu from infected animals. If you are planning a trip to any of these areas, the Centers for Disease Control and Prevention (CDC) recommend the following pre-travel precautions:

• Visit CDC's Traveler's Health Web page on Southeast Asia for up-to-date information about disease risks in the area you plan to visit.
• Get a seasonal flu vaccination, widely available on October 24. If you are vaccinated against seasonal flu, there is less chance of confusing human flu with avian flu. If you are traveling in a country where a human outbreak of avian flu occurs, authorities will likely quarantine anyone with flu-like symptoms to contain disease spread. CDC recommends updating all needed vaccinations 4 to 6 weeks before travel.
• Assemble a basic first aid travel kit: Include a thermometer, alcohol-based wipes and hand sanitizers, household disinfectant, and 2– or 3-ply surgical masks (such masks are not proven to protect against contracting flu, but may have some benefit, experts say).
• Identify in-country health resources prior to travel: Check your health insurance plan and consider additional medical evacuation insurance in case you become ill. Medical evacuation insurance information is online.

During travel to an affected area:

• Avoid all contact with poultry, including healthy appearing birds as well as sick or dead chickens and ducks. Avoid colorful markets in Asia that attract tourists, but often offer live fowl for sale. Avoid all surfaces contaminated with poultry secretions or feces.
• Wash your hands frequently: As with other infectious illnesses, cleaning your hands often with soap and hot water or hand sanitzers removes potentially harmful material from your skin and helps prevent disease transmission.
• Eat only thoroughly cooked poultry, including eggs and food containing poultry blood: Heat destroys influenza viruses.
• If you develop flu-like symptoms such as fever, difficulty breathing, or cough, contact an US consular officer: They can help you locate local medical services and contact family and friends. Other resources include: International SOS -- a fee-based, comprehensive, 24-hour, physician-backed medical and security assistance; MEDEX, which provides services including 24-hour access to coordinators who can help locate appropriate medical care providers, coordinate direct payment of covered medical expenses, and assist in other medical, legal, or travel situations; or IAMAT, International Association for Medical Assistance to Travelers, a nonprofit organization offering medical information to travelers.

After returning from travel:

• Monitor your health for 10 days.
• If you become ill with fever, cough, or difficulty breathing or if you develop any illness during this 10-day period, consult a health care provider. Before you visit your doctor, tell the provider the following: your symptoms; where you traveled; and if you have had direct contact with poultry. This way, your doctor is aware you have traveled to an area reporting avian influenza.

Another precaution to consider is discussing a prescription for an antiviral medication, such as Tamiflu, with your physician. Tamiflu can be taken in two ways. For prevention — one tablet a day lowers your chances of contracting flu. And if you do come down with flu-like symptoms, two tablets of Tamiflu daily can reduce seasonal influenza's severe symptoms and the duration of the illness. Laboratory studies suggest it may also protect against avian flu. It's worth noting that the drug is relatively expensive — about $10 a pill, which can add up fast if you are taking it for prevention over an extended period.