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The Rediff Special/ rediff News Bureau
So, what exactly is bird flu?
February 20, 2006
India, France and Iran are first-timers. Authorities in Bulgaria are testing a man for bird flu. Indonesia has confirmed the death of 19 so far, while Egypt and Nigeria are trying hard to control its spread. Are we at risk? Read on.
What is Bird Flu?
Also referred to as Avian Flu, this is a type of influenza virus. These viruses can infect a number of animal species, including pigs, horses, and several species of mammals. The ones that infect birds are called 'avian influenza viruses.' Wild birds are often the natural hosts, but avian influenza viruses do not usually infect humans directly.
Avian influenza is caused by the Influenza A virus, first identified in the early 1900s in Italy and now present worldwide. If you're wondering about the names often given to these viruses, avian flu virus subtypes are labelled according to an H number (for hemagglutinin) and an N number (for neuraminidase).
Each subtype has mutated into a variety of strains, but most are now extinct.
Where did the flu originate? How does it spread?
From wild birds. Wild waterfowl can be responsible for the primary introduction of infection into domestic poultry. This is different from SARS, which is caused not by an influenza virus but by a corona virus. Avian influenza spreads when infected birds shed the virus in the form of saliva or faeces. These then affect susceptible birds that come in contact with the contaminated matter, or contaminated food and water.
Avian influenza virus spreads in the air and manure and survives longer in cold weather. There is no evidence that the virus can survive in well-cooked meat though. The incubation period is 3 to 5 days. Symptoms in animals vary, but strong strains can cause death within a few days.
Can infected birds spread the influenza to humans?
Rarely. How this transmission from birds to people occurs is not known, but most human cases have been traced to direct contact with live infected birds or their droppings.
Can we still eat chicken and eggs?
Yes, it is safe to eat poultry and eggs, provided it is not undercooked. Runny eggs, for instance, may not be such a good idea. Avoiding unnecessary contact with live poultry is important, so you might want to avoid the live markets if the number of cases rises. For the moment, however, the government says the situation is well under control.
What are the symptoms, in birds and humans?
In humans, avian flu viruses cause similar symptoms to other types of flu, including fever, cough, a sore throat, muscle aches and, in severe cases, severe breathing problems and pneumonia that may be fatal. The severity of the infection will depend on an individual's immune system.
As for affected birds, these display symptoms like tremors, diarrhoea, staggering and paralysis. Human beings, especially children, who come in contact with live infected birds, their mucus, droppings or even feathers risk getting infected.
Can the virus spread from person to person?
There is no evidence of this yet. The virus could change though, and may then spread easily from person to person. The avian influenza and human influenza virus could mix, resulting in a new subtype. Thankfully, there is no indication of this yet.
Are there treatment options available?
There are certain anti-viral drugs available, but the need for using these does not exist at this point. However, if one is in direct contact with infected birds or a contaminated environment, an influenza anti-viral drug must be taken daily. Seek your doctor's advice on this issue.
What about precautions?
Apart from avoiding contact with live poultry, remember that the virus is sensitive to common disinfectants such as detergents. The government is currently disposing culled birds. It has also said that it is safe to consume well-cooked chicken and eggs as the Indian style of cooking -- deep-frying and boiling – kills the virus. Another thing working in our favour is the heat, as the virus cannot survive the harsh Indian summer.
Beating bird flu
While it may appear to be just bad news from around the world, the good bit is bird flu can be defeated. Vietnam -- the world's worst-hit country with 93 human cases and 42 deaths -- has managed it.
Bird flu has an incubation period of one to two days in poultry and five to seven days in humans. Under World Health Organisation guidelines, a country is designated disease-free when no new cases have been recorded for 21 days. Vietnam did it with a combination of vaccination, culling and public communication – a strategy the Indian government has already begun to implement.
Vigilance is the key. Ducks can also carry the virus without showing symptoms, and it can also persist in the soil and water. For the moment though, Vietnam's victory has given the rest of the world a much-needed shot of hope.
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