The highly pathogenic avian influenza subtype A (H5N1) strain has caused major outbreaks in Asia, and recent evidence of human-to-human transmission has caused health officials to increase preparedness and response tactics.
World Health Organization officials say the world is in the “gravest possible danger of a pandemic,” fearing an outbreak could kill millions of people, according to their website.
Dr. Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases, said human-to-human transmission was demonstrated when a young Thai girl was infected by chickens, and the girl’s mother and aunt, who had no previous exposure, subsequently both contracted the deadly strain. The findings appear in the Jan. 27 issue of the New England Journal of Medicine.
“The mother and aunt contracted the H5N1influenza from close contact with the child,” Fauci said in e-mail.
To date, 55 humans have been infected with the H5N1 virus, claiming 47 human lives.
Outbreaks among poultry occurred in various parts of Asia during late 2003 and early 2004. At that time, more than 100 million birds died from the disease or were sacrificed.
Annual outbreaks of influenza are due to mutations in the surface proteins of the viruses that enable the disease to evade any immunity humans may have developed after exposure to the virus.
“Because it is a strain that nobody has any natural immunity to, it would probably spread around the world very fast,” said UHS Clinical Services Manager and epidemiologist Craig Roberts.
CDC Director Dr. Julie Gerberding said the deadly Spanish flu of 1918, which claimed between 20 and 40 million lives, did not appear suddenly but mutated gradually into the deadlier form.
“That’s why it’s important to have flu vaccine and antivirals … ready when it starts to emerge,” Gerberding said in a release.
Epidemiologist and Influenza Surveillance Coordinator Tom Haupt of the Wisconsin Division of Public Health said the novelty of the avian flu poses a challenge for mass production of vaccines.
The federal government has already purchased two million doses of a vaccine made from a bird flu virus strain taken from a Vietnam man who died of the disease.
In an effort to catch U.S. cases early, the CDC has contacted state and local health departments, hospitals and doctors to urge them to increase disease surveillance.
The Wisconsin State Laboratory of Hygiene and the Wisconsin Division of Public Health initiated a surveillance program in Feb. 2004 designed to test specimens from patients with bird flu symptoms who have returned from southeastern Asia within 10 days prior to symptom onset.
“We are going above and beyond the standards as far as monitoring for avian influenza and also working for detecting any flocks that may have it in Wisconsin,” Haupt said.
UHS is also actively involved with local and state health departments in coordinating a response to a potential epidemic.
“There are contingency plans in place to set up mass vaccination clinics if we needed to immunize the entire county … including the campus,” Roberts said.
-Rachel Patzer contributed to this article
