February 2004 Health Alert
Avian Influenza (Bird Flu) Outbreak (info from CDC)
An outbreak of avian influenza, more commonly known as bird flu, is affecting bird populations in countries throughout Asia. Human cases have also been reported.
Influenza A (H5N1) is a subtype of the type A influenza virus. Wild birds are the natural hosts of the virus, hence the name avian influenza or bird flu. The virus was first isolated from birds in 1961. The virus circulates among birds worldwide. It is very contagious among birds and can be deadly to birds, particularly domesticated birds like chickens.
The virus does not typically infect humans. However, in 1997, the first instance of bird-to-human transmission was documented in Hong Kong; the virus caused severe respiratory illness in 18 people, of who 6 died. So far these viruses have not been capable of efficient human-to-human transmission. This is something that is being watched carefully and is being investigated during this current outbreak.
In the current outbreak cases of avian influenza have been confirmed among poultry in Cambodia, China, Hong Kong, Indonesia, Japan, Korea, Laos, Thailand, and Vietnam. The outbreak of bird flu has resulted in human cases in Vietnam and Thailand. Deaths have been reported. At this time, it is believed that these cases resulted from contact with infected birds or surfaces contaminated with excretions from infected birds.
All influenza viruses can change. It is possible than an avian influenza could change so that it could infect humans and could spread easily from person to person. Because these viruses commonly do not infect humans, there is little or no immune protection against them in the human population. If an avian influenza virus were able to infect people and be easily spread from person to person, an "influenza pandemic" could begin
For travelers, CDC advises that travelers to countries in Asia with documented H5N1 outbreaks should avoid poultry farms, contact with animals in live food markets and any surfaces that appear to be contaminated with feces from poultry. Health departments and health care professionals have been provided guidance on enhanced surveillance to help identify possible cases that might be imported into the United States