Tuesday, December 20, 2005


Q: What is bird flu?

Like humans and other species, birds are susceptible to flu. There are 15 types of bird, or avian, flu. The most contagious strains, which are usually fatal in birds, are H5 and H7. The type currently causing concern is the deadly strain H5N1. Even within the H5N1 type, variations are seen, and slightly different forms are being seen in the different countries affected in this outbreak. Migratory wildfowl, notably wild ducks, are natural carriers of the viruses, but are unlikely to actually develop an infection. Domestic birds are particularly susceptible in epidemics. This is why the confirmation of H5N1 in birds in Turkey and Romania is causing concern. Pakistan has seen cases of the H7 and H9 strains of bird flu in poultry, but no cases of these strains have been passed to humans.

Q: Is it possible to stop bird flu coming into a country?

The fear, after the Turkish and Romanian findings, is that H5N1 will spread across Europe. Because it is carried by birds, there is no way of preventing its spread. But that does not mean it will be passed to domestic flocks. Experts say proper poultry controls - such as preventing wild birds getting in to poultry houses - which are present in the UK, should prevent that happening. In addition, they say monitoring of the migratory patterns of wild birds should provide early alerts of the arrival of infected flocks - meaning they could be targeted on arrival.

Q: How do humans catch bird flu?

Bird flu was thought only to infect birds until the first human cases were seen in Hong Kong in 1997. Humans catch the disease through close contact with live infected birds. Birds excrete the virus in their faeces, which dry and become pulverised, and are then inhaled. Symptoms are similar to other types of flu - fever, malaise, sore throats and coughs. People can also develop conjunctivitis. Researchers are now concerned because scientists studying a case in Vietnam found the virus can affect all parts of the body, not just the lungs. This could mean that many illnesses, and even deaths, thought to have been caused by something else, may have been due to the bird flu virus.


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