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FACTBOX-Key questions and facts about bird flu
06 Aug 2004
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LONDON (AlertNet) - A virulent strain of avian influenza, which first broke out in Hong Kong in 1997, killed millions of chickens and 24 people when it swept across much of Asia in the first part of 2004. Following are some key questions and facts about bird flu.
WHAT IS BIRD FLU?
The poultry disease is an animal type of influenza -- the H7N7 "classical" strain of avian influenza. Avian influenza can range from a mild disease that has only minor effects to a highly infectious version that is fatal. It spreads in the air and in manure.
It can also be transmitted by contaminated feed, water, equipment and clothing. Clinically normal waterfowl and sea birds may introduce the virus into flocks. Broken contaminated eggs may infect chicks in the incubator.
IS BIRD FLU HARMFUL TO HUMANS?
Human fatalities from avian influenza were unknown before 1997, when six people in Hong Kong died after being infected with the H5N1 strain. Last year it infected a father and son in the crowded city.
Last April, a Dutch veterinarian who had been working on a farm infected with bird flu became ill with an H7 strain of the disease and died of pneumonia. The vet did not take medication against avian and human flu. Rules have been tightened to ensure anyone who comes in contact with infected farms does so.
Other Dutch farm workers have come down with eye infections caused by the virus and a few have also had influenza symptoms, but these have all been successfully treated with medication.
South Korea, which has already culled nearly two million chickens and ducks, reported last Tuesday the first new case of avian flu in more than a week, dashing hopes that the outbreak was subsiding.
Japan reported its first bird flu outbreak in years last week and five people have died of the disease in Vietnam.
COULD BIRD FLU BECOME A HUMAN EPIDEMIC?
Although avian flu is very infectious in birds, it does not spread easily among humans.
There is a danger, however, that an avian virus mixes with a human influenza and forms a new disease. The new virus could share genetic material from both viruses, being highly infectious like human flu and dangerously fatal like the avian variety.
Dr. Shigeru Omi of the World Health Organisation has said the consequences would be dire if the virus latched on to the human influenza virus and spread among people, who have little immune protection against the strain.
New influenza strains have caused pandemics, most recently in 1956-1957 and 1967-1968, killing a combined 4.5 million people.
CLINICAL DIAGNOSIS
The World Organisation for Animal Health (OIE) says the incubation period for the disease in poultry is 3-5 days. It has various affects on birds, ranging from severe depression to drastic declines in egg production and sudden deaths. There is no treatment.
(Compiled by Reuters Editorial Reference Unit)
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