To snip the wings of the Avian flu

ROUND-THE-CLOCK CARE: Disposable masks, gloves, polythene bags, Respiratory Protective Equipment (RPE), and mobile de-contamination units are put into action for curbing the spread of bird-flu.

The "highly pathogenic" Asian strain of the H5N1 virus is the strain currently causing concern in this year's bird-flu epidemic.

Scientists have discovered four different subtypes of H5N1 so far, and while all are deadly to birds, and can cause disease - and death - in humans, H5N1 is overwhelmingly a disease that affects birds - and not humans. Migratory wildfowl, notably wild ducks, are natural carriers of the viruses, but are unlikely to actually develop an infection. The risk is that they pass it on to domestic birds, who are much more susceptible to the virus.

It is true that humans have been infected, but almost all have been poultry workers who have come into intimate contact with birds. H5N1 cannot pass easily from human to human. As of January 2008, the World Health Organization (WHO) had confirmed 348 cases of H5N1 in humans in Azerbaijan, Cambodia, China, Djibouti, Egypt, Indonesia, Iraq, Lao People's Democratic Republic, Myanmar, Nigeria, Pakistan, Thailand, Turkey and Vietnam, leading to 216 deaths.

For the most part, humans have contracted the virus following very close contact with sick birds.

There may have been examples of human-to-human transmission, but so far not in the form which could fuel a pandemic. If the virus gained the ability to pass easily between humans the results could be catastrophic.Worldwide, experts predict anything between two million and 50 million deaths.However the mortality rate - which presently stands at around 50% of confirmed cases - could decline as it mutates, they say.

There is no failsafe way of preventing its spread. Experts say proper poultry controls - such as preventing wild birds getting in to poultry houses - are vital. 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.

There is not yet a definitive vaccine, but prototypes which offer protection against the H5N1 strain are being produced.

But antiviral drugs, such as Tamiflu which are already available and being stockpiled by countries such as the UK, may help limit symptoms and reduce the chances the disease will spread. Concerns have been prompted by news that patients in Vietnam have become partially resistant to the Tamiflu, the drug that doctors plan to use to tackle a human bird flu outbreak.

Scientists say it may be helpful to have stocks of other drugs from the same family such as Relenza (zanamivir).

Experts say avian flu is not a food-borne virus, so eating chicken is safe. The only people thought to be at risk are those involved in the slaughter and preparation of meat that may be infected. However, the Who recommends, to be absolutely safe all meat should be cooked to a temperature of at least 70C. Eggs should also be thoroughly cooked.

Steps have been taken to try to stop the disease spreading among birds. Millions of farmyard birds have been culled, while millions more have been vaccinated and confined indoors. Areas where the disease has been found have been isolated and some countries have banned imports of live birds and poultry products.

In January 2006 international donors pledged $1.9bn (£1.1bn) in the fight against bird flu, while the World Health Organization has devised a rapid-response plan to detect and contain a global flu pandemic.

There are also measures recommended when a wild infected bird is found, including protection and surveillance zones.

On being asked what measures can be taken to prevent bird flu in Inida, Union Health Minister A. Ramadoss, said that India was yet to import the Tamiflu vaccine.

Moreover, the procedures for culling birds does not include disposing of the carcasses in a safe manner as the dead birds in West Bengal, India are simply piled up while more are beng killed by the minute.

The European Union has suggested that Asian countries, instead of culling livestock, should increase the disease-resistance of susceptible animals by strategic vaccination.

Group members

• Saumya Ancheri (saumya.ancheri@gmail.com)
• Sumit Dasgupta (saumit_acj@rediffmail.com)
• Ranjani Rajendra
• MJ

 Source:

www.bbc.co.uk

www.bio-medicine.org

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