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Bird flu –
what you need to know |
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Q: What is bird flu? Bird flu is a viral disease, very similar to common-or-garden influenza, which exists in birds, particularly poultry, and was first noted by veterinary scientists in the early 1900s. The current scare concerns a strain called H5N1. It spreads rapidly among large flocks of domestic poultry, and it is thought that parts of Southeast Asia and China, where people, chickens and ducks live cheek-by-jowl in often unsanitary conditions, may have provided the ideal crucible for a bird flu epidemic. Q: How do humans get it? Most diseases which affect animals do not affect humans, and vice versa, but there are exceptions. In 1997 the first cases of “human” bird flu were discovered in Hong Kong. It seems people can catch the virus through contact with infected live birds. The virus is excreted, and people may inhale these germs as dust when these droppings dry out. The virus has also turned up in some Vietnamese pigs. Q: What are the symptoms? Pretty much the same as in other influenzas --- sufferers quickly develop a high temperature, painful joints, sore eyes, sore throat and a cough. In more than half the cases seen so far the victim dies, usually of acute respiratory problems. One victim, a child, was taken to hospital with diarrhea and quickly slipped into a coma without developing other flu-like symptoms. Q: How many people have caught the disease? So far, there have been about 124 confirmed cases in Indonesia, Vietnam, Thailand and Cambodia. But this figure may be an underestimate, as the symptoms of bird flu are so similar to those of a host of other diseases. Sixty-three of these people have died. Ten countries have been affected, and 200 million birds have died or been culled. Q: How does the death rate compare with other viruses? Badly. In 1918, only about three per cent of people infected with “Spanish” (in fact it had nothing to do with Spain) flu died. This makes avian flu potentially more than 10 times as lethal. The death rate from SARS, which emerged in 2002, was about 10 per cent of those infected. |
Q: Can you catch bird flu from another person? That is the million ringgit question. It seems that it is possible to catch the disease from an infected human being, but only in special circumstances where there is a lot of contact --- say from child to mother or the other way round. So far there have not been people catching the infection who have had direct close contact with other people who are ill, although the fear is this could change. Q: Why be so worried? If bird flu stays the way it is now, there would be no cause for real concern. The fear centre on what would happen if bird flu mutates --- either into a form which is more infectious, or by combining its DNA with an existing, human-adapted influenza strain which would facilitate the spread into the population --- a so-called “antigenic shift”. Of particular concern is the research which showed that the 1918 influenza pandemic was caused by a strain of bird flu --- which again probably originated in Asia. H5N1 is considered a good candidate for the next “doomsday” influenza ---one which spreads through the human population worldwide. Q: If the virus DOES mutate, and spreads, what will happen? A lot of people will die. Once it “learns” how to infect humans with ease, it could spread like wildfire in particles of saliva expelled through coughing and sneezing. If we are lucky, modern medicine (and probably some fairly fierce quarantine restrictions) could limit the pandemic to a couple of million deaths worldwide. If we are unlucky, tens of millions could die. Q: Can the disease be cured? No. Influenzas are viral diseases, and antibiotics (which only kill bacteria) will not work. However, new antiviral drugs called neuraminidase inhibitors are effective to a degree. But the best hope is a vaccine. No one infected with any virus has ever been truly “cured” by medicine. Q: Should I stop eating chicken? No. There is no evidence that actually eating cooked poultry meat can infect people. You need to be in close proximity to live, infected birds to stand a chance of catching the disease as it stands. |
Q: What is being done? Millions of birds have been culled to check the spread of the disease. Killing sick birds and, importantly, those which have been in contact with them, as well as proper disposal of the carcasses is needed. As the disease spreads, it is likely we will see more and more countries imposing restrictions on the import and export of poultry. Q: What can be done? The antiviral drug, Tamiflu, reduces the severity of flu symptoms and can also mean that you are ill for less time. But recently, the science journal Nature released a paper showing that a strain of the virus resistant to Tamiflu seems to have evolved, suggesting other drugs will be needed. Q: When is a vaccine likely to be available? It is impossible to produce a wholly effective vaccine until the pandemic begins --- as scientists need to work with the actual, mutated viruses that have gained a hold in the population which will be similar to, but not the same as, H5N1. It may take four to six months to develop an effective vaccine. Q: What about existing flu jabs? These will give no protection against avian flu or its putative mutant cousins, but by reducing the prevalence of influenza in the population as a whole, current vaccines may reduce the amount of viruses in circulation and hence make it less likely that human strains of bird flu will swap genes with the avian variety to produce a “doomsday” strain. Q: If our fears do not materialize, are we out of the woods? No. Even if the current strain of bird flu dies out, health experts pretty-well all agree that an influenza pandemic is --- sooner or later --- almost inevitable. --- DM.
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