Risk abroad of avian virus is still unclear, health officials say

Travelers worried about the spread of avian influenza in Asia do not need to cancel trips, though they should take common-sense precautions, U.S. public health experts say.

The World Health Organization reported 13 confirmed human cases of bird flu in Vietnam and four in Thailand, resulting in 12 deaths, as of the Travel section’s deadline Tuesday. Both countries’ poultry flocks had suffered outbreaks of a virulent form of the flu virus called H5N1, according to the WHO. The disease also had been confirmed among birds in Cambodia, China, Hong Kong, Indonesia, Japan, South Korea and Laos, according to the U.S. Centers for Disease Control and Prevention.

Wild birds are natural hosts of the virus, according to the CDC, and it spreads easily among domesticated birds such as chickens. The animals catch the virus when they come into contact with the saliva, nasal secretions or feces of an infected bird. Until recently, the human cases in Vietnam and Thailand were thought to have occurred when people were exposed to infected birds or contaminated surfaces. But last week, cases in Vietnam renewed fears that the virus may mutate and spread from person to person. Officials emphasize, however, that they have no proof this has, or will, happen -- meaning travelers who limit their exposure to birds theoretically limit their exposure to the virus as well.

“There’s no evidence, at least that I know of so far, of person-to-person or food-to-person” transmission, says Dr. Peter Katona, associate professor of clinical medicine at UCLA’s David Geffen School of Medicine and an infectious disease specialist.

“The big question, of course, is whether the strain that is killing birds right now becomes transmissible among humans,” as it did in past years, says Dr. David Dassey, deputy chief of Acute Communicable Disease Control for the Los Angeles County Department of Health Services. Right now, he says, “there is no reason to cancel trips.”

At the center of a WHO investigation in Vietnam is a 31-year-old man, his 28-year-old wife and his two sisters, 23 and 30, who came down with the disease; only the wife survived. Officials think the man and one sister handled duck while preparing a meal Jan. 4. WHO officials are trying to determine whether one or both of the sisters caught the virus from their brother while caring for him.

One promising sign: The strain involved in the current outbreak has been analyzed, and the CDC says that all the virus’ genes are of bird origin. That means the virus has not acquired genes from human influenza viruses, a step that would boost the likelihood of person-to-person transmission.

The CDC is not advising travelers to change plans, spokeswoman Christine Pearson says. But the agency suggests that travelers bound for affected areas avoid contact with farm birds, live animals in markets and any surfaces that may be contaminated.

Dassey says the same habits that reduce the risk of other diseases work for bird flu too: Wash hands frequently with soap or use hand sanitizers.

UCLA’s Katona says he isn’t worried about eating chicken or eggs in affected countries as long as those products are cooked.

He also advises travelers to keep a proper perspective. Destinations afflicted with bird flu sometimes are stricken with malaria, “and there are a lot more cases of malaria than avian flu.”

For more information go to www.who.int or www.cdc.gov or call the CDC’s avian flu hotline, (888) 246-2675.

Healthy Traveler appears every other week. Kathleen Doheny can be reached at kathleen doheny@earthlink.net.