Thursday, May 05, 2005

Taking bird flu seriously

I guess the Philippines takes bird flu seriously. Appearance of the disease in poultry in South Sulawesi (Indonesia), has alarmed the Agriculture officials in the Philippines island of Mindanao, which is only a few miles over water. A "Bird Summit" bringing together the Ministers of Health and Agriculture was held recently in Davao City to educate mayors, governors and officials in agriculture to the danger and encourage them to adopt measures to prevent entry of the disease into the island nation. Whether this kind of jawboning of local officials will be effective is doubtful, however. It would seem only a matter of time before the disease reaches the Philippines.

Vietnam, fighting a protracted war against the virus (and losing), is turning to poultry vaccination, a measure they once rejected (New Scientist). 600,000 chickens in Ho Chi Minh City will be vaccinated against influenza A/H5N1 in an experimental program. The country has culled more than 2 million birds in an effort to halt the disease that has infected 69 people and killed 37 since January 2004. But the culling effort has been futile. A survey of birds in the Mekong River Delta recently founded 70% of the ducks and 22% of the chickens infected. The virus is thus firmly entrenched. But vaccination is controversial. The birds stay infected but remain well, so detection of new infection in poultry becomes more difficult. The virus may also come under different and novel selection pressures, leading to evolution in unexpected directions. The current H5N1 is thought to have emerged from China, where vaccination is practiced. On the plus side, vaccinated birds seem to shed significantly less virus, thus reducing spread to humans.

Thailand is another afflicted nation where vaccination is being tried, although limited to fighting cocks and free range chickens and ducks (thus excluding large industrial farming operations). But Thailand has also had an active local program of health volunteers who look for signs of the disease in birds, collect samples for lab analyses and generally act as intermediaries between the Ministry of Public Health in Bangkok and local villagers. Thai officials now claim this strategy has worked and they have declared the country bird flu free, although at the cost of 66 million birds culled. But declaring the country free of bird flu sounds like wishful thinking, and as the New Scientist notes:
Southeast Asia and southern China are perfect breeding grounds for bird flu: They have dense populations, huge poultry farming operations and migratory birds. In an increasingly integrated global economy, these places are linked to the rest of the world by hundreds of commercial flights. That allows disease to spread quickly from Southeast Asia to Europe or the USA. We're all living in the same risk pool now, Aldis says.

So the entire world depends on the vigilance of public health officials and average citizens in places such as Thailand's Suphan Buri Province, a 90-minute drive northwest of Bangkok, the capital. At a time when the bird flu threat seems to be fading in Thailand, these front-line health workers also must fight complacency.
If they want advice on complacency, they should visit the US. We lead the world in that category.