Bird Flu Round-Up

by DemFromCT

Oh, it's still out there. It's hard to balance the need to inform with the need to curb sensationalism, but regardless of how it's reported, avian flu is making its way through Southeast Asia, particularly Vietnam, Thailand and now Indonesia. Effect Measure (the public health blog) tracks efforts to inoculate the poultry industry in the Phillipines by various means, none likely to be completely successsful.

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.

Meanwhile Vietnam is getting literal with the inoculation idea:

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.

However, according to WHO,  the afflicted countries are ill-equipped with the rapid response techniques that would be necessary to halt a human pandemic:

Cases of humans being infected with bird flu are rising in Asia, and there are worrying signs that the virus is mutating into a more transmissible form. But experts say bureaucratic delays will probably defeat attempts to stop a human pandemic in its tracks.

Klaus Stöhr, who coordinates the influenza programme of the World Health Organization (WHO), says there is only one option for extinguishing an emerging human pandemic: rapid identification of cases, and treatment of patients and all their contacts with the antiviral drug Tamiflu (oseltamivir phosphate). Modelling studies suggest this should work if action is taken quickly enough¹.

The models predict that there will be only a short window of opportunity in which to act: up to 30 days after a new case is detected. But the Vietnamese health ministry often takes two to four weeks to declare cases, according to the WHO.

"This leaves just a few days to intervene, making it very unlikely that we could stop a virus," says Stöhr. "Without fast reporting and detection of cases, the world is gambling away the small (and unproven) chance we have of stopping an emerging pandemic in its tracks."

Catch more details of those "worrying signs" here. A little less virulence in human cases means a little more spread.

In Asia, there are hints that the virus is indeed changing. "Incomplete evidence suggests that there may be a shift in the epidemiology of the disease," says Stöhr. "More clusters are being seen than last year, older people are now coming down with the diseases, and more cases are milder." Taken together, these characteristics could indicate that the virus is becoming less virulent and more infectious, he says, which could signal the start of a pandemic.

Stöhr goes on to say it's hard to know how much to worry. But proper public health policy consists of planning for the worst, not just hoping for the best. We've already seen what happens when the faith-based approach is applied to other areas of science.

Comments

[~DS~]

A few weeks ago a lady at work came back from Indonesia with some kind of bug. My wife and I both ended up getting it. I've never had a flu hit me like this before. It lasted for two weeks, the first few days I literally thought I was going to have to go to the ER. I wonder if that was one of these bird flus?

[DemFromCT]

Hey, DS. Thanks for stopping by TNH. As noted over at Daily Kos, bugs, flus and other viral illnesses are easily spread these days by airport travel.

It's still (the tail end of) flu season in some parts of the country (some outliers and straggler infections), so not all flus come from the airport, though.

[DemFromCT]

The New England Journal of Medicine covers our lack of preparation; the Effect Measure write-up is here.