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Most people know that bird flu is beginning to emerge as a serious health threat to the world. There are real concerns and in this article we give answers to 10 questions which many individuals are asking about bird flu.
1. What is Bird Flu?
Avian influenza or 'bird flu' is a highly contagious disease of birds, caused by influenza A viruses. In birds, the viruses can present with a range of symptoms from mild illness and low mortality, to a highly contagious disease with a near 100% fatality rate. The bird flu virus currently affecting poultry and some people in Asia is the highly pathogenic H5N1 strain of the virus.
As the virus can remain viable in contaminated droppings for long periods, it can be spread among birds, and from birds to other animals, through ingestion or inhalation. All bird species are thought to be susceptible to avian influenza. Migratory birds such as wild ducks and geese can carry the viruses, often without any symptoms of illness, and show the greatest resistance to infection. Domestic poultry flocks are particularly vulnerable to epidemics of a rapid, severe and fatal form of the disease.
2. Can Bird Flu Infect People?
People are rarely infected with bird flu viruses. Those who have become infected have had close direct contact with infected birds. The first documented cases of bird flu infecting people occurred in Hong Kong in 1997 and this was also the H5N1 strain of virus. Investigation showed that close contact with live infected poultry was the source of the infection. According to the World Health Organization (WHO), there is mounting evidence that the H5N1 strain has a unique capacity to jump the species barrier and cause severe disease, with high mortality, in people.
3. Can Bird Flu Travel From Person to Person?
There is no firm evidence that the H5N1 strain which caused the outbreaks in South East Asia has acquired the ability to pass easily from person to person or to sustain transmission. So far, while some instances of spread from one person directly to another have been reported, these have been isolated one-off occurrences with no further spread to people, and the route of transmission remains unconfirmed.
4. Have There Been Previous Outbreaks of Bird Flu Affecting People?
The first documented cases of bird flu in people appeared in Hong Kong in 1997, when 18 people infected with an H5N1 virus strain were admitted to hospital, six of whom died. The source of infection in most cases was traced to contact with diseased birds on farms, and in live poultry markets. As of 13 October 2005, 117 reported cases of H5N1 infection in people have occurred in four countries – Thailand, Vietnam, Cambodia, and Indonesia. Sixty of these have been fatal.
5. What is the Source of the Current Outbreak of Bird Flu?
The outbreak now concerning health experts began in poultry in South Korea in mid-December 2003, and has affected birds in many countries in Asia, Russia, and most recently Turkey and Rumania. It involves a variant of the same virus subtype as that associated with the 1997 Hong Kong outbreak.
6. What is the Risk of a Human Influenza Pandemic?
A pandemic can be broadly described as a massive epidemic. It occurs on a much greater scale than an epidemic, spreading around the world and affecting many hundreds of thousands of people across many countries. Experts are concerned that the virus could adapt, giving it greater affinity for humans. Or that it could exchange genes with a human flu virus, thereby producing a completely new virus strain capable of spreading easily between people, and causing a pandemic. By necessity, if a new strain were to occur then few people, if any, would have a natural immunity to it.
7. What Can I Do to Protect Myself and my Family?
There is some evidence that recent H5N1 viruses are susceptible to a class of antiviral drugs called neuraminidase inhibitors. The UK Government is expanding its stockpile of antiviral drugs against the contingency of a flu pandemic, whether due to an H5N1 or another new strain. On 1 March 2005, the Health Secretary announced the procurement of 14.6 million treatment courses of the antiviral, Tamiflu - enough to treat a quarter of the UK population. Individuals can purchase Tamiflu privately. The manufacturer, Roche, is working hard to supply what is required. World-wide demand, however, has increased dramatically recently and there may be shortages.
8. Is a Vaccine Currently Available for Bird Flu?
The present position is that there is no vaccine for bird flu. There are, however, several potential vaccines at various stages of testing and production. Whether these will be suitable for use against a new pandemic flu strain depends on how much the pandemic strain may have mutated and changed from the original H5N1 virus strain used to create the vaccine.
9. What is the Advice for Travellers?
Travellers to areas experiencing outbreaks of the disease in poultry are recommended to avoid contact with live animal markets and poultry farms.
Travellers should not attempt to bring any live birds or poultry products back to their own country.
10. How Can I Keep up-to-date With Bird Flu Matters?
The following organisations have sections on avian influenza which provide useful and regularly updated information: Health Protection Agency http://www.hpa.org.uk/infections/topics_az/avianinfluenza/menu.htm DEFRA http://www.defra.gov.uk/animalh/diseases/notifiable/disease/avianinfluenza.htm World Health Organization http://www.who.int/csr/disease/avian_influenza/en/index.html UN Food and Agriculture Organization http://www.fao.org/ag/againfo/subjects/en/health/diseases-cards/special_avian.html Bird flu has the potential to be the basis of an influenza pandemic. The experts are predicting that there will be a pandemic, although it is not possible to say when it will occur. The message is to be alert and be aware of the advice being given by your government.
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