Health Leader, Bird Flu: Spreading its Wings?

STORY BY

Sonora Hudson

Viruses are versatile and cunningly adaptive. Bird flu is showing a particular talent for survivability.

Data from countries infected with the avian, or bird, (A/H5N1) flu virus suggest that it may be changing in ways that could result in a greater possibility of human-to-human transmission.

According to the May meeting of the World Health Organization (on the status of bird flu on Humans in Asia), features of human H5N1 infections in northern Viet Nam from January to April 2005 showed:

an increased number of clusters of cases in the north, compared with the south;
a longer interval between the first and last cases in the clusters;
detection of infections described as “subclinical” (showing less severe symptoms);
an expanded age range of cases; and
fewer fatal cases.

Though fewer deaths and lighter symptoms sounds good, these findings create concern that the virus may be becoming more infectious for humans and more genetically diverse. Data also demonstrate that the virus continues to evolve and poses a potentially growing threat of a pandemic (global epidemic). One case of resistance to oseltamivir, the antiviral currently used to treat patients infected with the virus, was also reported.

“This flu strain is surfacing continuously in Asia,” says infectious disease expert Luis Ostrosky-Zeichner, MD, assistant professor in the Department of Internal Medicine at The University of Texas Medical School at Houston. “Authorities are on top of it and monitoring closely. But with global transportation, occurrence in other countries is a possibility. The public by and large is not immune.”

Status in Asia Today

A total of 97 human cases and 53 deaths had occurred in Viet Nam, Thailand and Cambodia by early May, according to WHO. The presence of this virus strain also has been confirmed in birds in the People’s Republic of China, Hong Kong, Indonesia, Japan, Laos, Pakistan and South Korea.

More than 100 million poultry birds have been killed or culled since late 2003. Although experts cannot say with certainty how many humans could be affected by a pandemic, WHO estimates that two to seven million people would die and tens of millions would require medical attention during a “best-case” scenario. The range could be anywhere from two to over 50 million deaths. Non-bird flu usually causes about 36,000 deaths worldwide annually during seasonal outbreaks.

At sites where infection in poultry has been controlled or eliminated, human cases no longer occur, so prompt action in infected areas is a primary strategy. However, the virus has been shown to survive for three months in contaminated manure at cool temperatures and for up to four days at 72ºF and for more than 30 days at 32ºF in water. Research has shown that one gram of contaminated manure can contain enough virus to infect one million birds. Migratory birds, especially ducks, that may not show any symptoms, also transmit the virus.

The Pig Link

Pigs are a special risk, since they are susceptible to both bird flu and the regular type of human flu, which could allow the virus to evolve to a strain that could be transmitted from human to human. According to the United Nations Food and Agriculture Organization, in Viet Nam the H5N1 virus was detected in pigs raised on farms that also raised chickens infected with the virus.

Asia Travelers Take Note

As a preventive measure, the US government recently enacted a ban on the importation of birds and eggs from the infected countries. The US Occupational Safety and Health Administration also has issued guidances for farm workers/animal handlers, laboratory workers, medical workers that transport/treat avian flu patients, food handlers, airline flight crews and travelers.

Travelers to infected countries are advised to

avoid areas with live poultry, such as live animal markets and poultry farms,
to monitor their health for 10 days after return,
and to consult a health-care provider if they become ill with fever or respiratory symptoms during the observation period.
They should also notify the health-care provider of their symptoms and recent travel before seeking treatment.

“People here are taking preventive measures in case of a pandemic,” Ostrosky says. “Many preparations have been occurring, such as educating health care personnel how to recognize and isolate cases quickly, stockpiling antivirals and developing flu plans for hospitals. In addition, much research is underway.

Last Updated: 7-20-2005

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About Dr. Ostrosky:

Dr. Luis Ostrosky-Zeichner is an associate professor in the Division of Infectious Diseases at the UT Medical School.

See Dr. Ostrosky also at:

Health Tip:

Packing Bag Lunches Safely

If you pack lunches for your child to take to school, be careful that you do not accidentally expose them to foodborne illness.

Bagged lunches, especially those containing perishable foods, need to be packed and handled properly in order to keep the food safe. In general, perishable foods should not be left at room temperature for more than two hours. If left out too long, the temperature of the food can enter the danger zone where bacteria grow most rapidly, which is between 40 and 140 degrees Fahrenheit.

Below are some tips to help families pack bagged lunches safely:

Pack foods that are nonperishable and won't require refrigeration.
If you do pack perishable foods such as luncheon meats or prepackaged cheese and crackers, include a frozen gel pack or a frozen juice carton with the food in an insulated lunch bag or box.
Pack only the amount of perishable food that your child can eat at lunch.
Preparing lunches the night before and storing them in the refrigerator until you pack your child's lunchbox in the morning can help keep food cold longer the next day.
Don't reuse packaging materials such as paper or plastic bags, aluminum foil, etc. as they can contaminate other foods and cause foodborne illness. Have your child discard all used food packaging and paper bags after lunch.

Before eating lunch or snacks at school, make sure your child washes his or her hands with soap and warm water for at least 20 seconds. If your child's school does not have a handwashing program in place, encourage them to adopt a such a program, as handwashing is one of the best ways kids and parents can protect health and stop the spread of germs.