Bird flu – the pandemic clock is ticking
Box 3 | Controlling an outbreak
Once a virus with the ability to cause a pandemic exists, then control of an outbreak of the virus becomes very important in preventing its spread. This is true not only of the flu, but of any virus that can cause a zoonotic infection.
Surveillance, development of vaccines, preparedness for an outbreak and planning for a pandemic are all important means of controlling an outbreak. The behaviour of H5N1 virus is being monitored by researchers from the World Health Organization (WHO) and the United States Centers for Disease Control, looking for early signs that it has changed or altered its ability to infect people, particularly from other people.
Limiting the number of infected animals that are the source of disease in people is important in controlling outbreaks of the flu in people. For this reason, authorities in Asian countries have culled millions of infected poultry. A number of Asian countries also vaccinate poultry against bird flu. Some scientists are concerned that widespread vaccination will allow the virus to remain in the bird population without causing disease and would put further pressure on the virus to change.
However, it is not feasible to vaccinate all poultry in Southeast Asia. In Vietnam for example, 90 per cent of chickens are from ’backyard farmers’ who live in close proximity to the animals. Some countries are simply too poor to vaccinate their poultry. Such countries are relying on public awareness campaigns to prevent the spread of H5N1 from animals to people. People are being urged to modify traditional practices so that chickens, ducks and pigs are separated on farms and in market places.
On a broader scale, countries can prevent the export and import of infected animals, products or people. Australia does not import products from countries known to have H5N1, but airline passengers need to be checked by quarantine inspectors for bird products in their luggage. Medical professionals need to be alert to the disease in patients and poultry farmers need to recognise signs of the disease in birds.
Boxes
Box 1. An ever-changing virus
Box 2. Past flu pandemics
Box 4. Vaccines for pandemics
Box 5. Antivirals bring hope
Posted July 2005.