The Coming Influenza Pandemic?

February 9 Flu Update

Some Iraqi farmers are letting their birds loose rather than slaughter them and the lack of a proper shipping container has kept the tissue sample of a man suspected of dying of bird flu sitting in Baghdad despite reports it was being tested abroad.

Dr. Joseph Domenech of the UN's Food and Agriculture Organization answered "Nigeria" when asked which African country he had least wanted to see this virus pop up in. "Oh, yes," Domenech, head of the FAO's animal health service, said from Rome. "In Nigeria you have a lot of commercial farms ... (And) Nigeria as a whole is a heavily populated country."

It may be assumed that none of the 4 outbreaks -- the one in Kaduna confirmed yesterday and the other 3, currently under investigation --are primary outbreaks in Nigeria. Backyard poultry might have been their source of infection. The crucial questions are how far and how long has the virus been circulating in Nigeria. As remarked by Dr Karesh, for whose observations we are grateful, there are at least 3 possible introduction routes; all may have taken place earlier this year or even since fall 2005. In addition, as he rightly states, without good epidemiologic investigation in addition to genetic analyses, any conclusion is just speculation.

If widespread, surveillance and culling might not be feasible; mass vaccination should be considered.

The article was posted before we found out the strain in Nigeria is apparently Qinghai, that is, the same one found in wild birds at Qinghai Lake, then across Siberia, then in Turkey and around the Black Sea coast. That is exactly what one expects for wild bird spread. (The probability of that spread was also strongly supported by a PNAS paper this week, Chen et al.) This might theoretically be down to people shipping infected meat or poultry waste to the affected areas, but I can't see why that would all be exactly the same strain of H5N1 every time, and never the Z genotype that has dominated east Asian outbreaks.

Guus Koch, senior avian flu scientist at the Dutch Central Institute for Animal Disease Control, told Reuters he expected many EU countries to order their poultry indoors from March to prevent contact with migrating birds returning ck from Africa. The deadly H5N1 avian flu strain arrived in Nigeria this week in what is Africa's first bird flu outbreak. Wild birds have been blamed for spreading the disease westwards from east Asia into eastern Europe and Turkey. "There might still be some member states which are not convinced about the risk," Koch said. " Let say that there is an outbreak tomorrow in a free range farm -- how can a minister of agriculture defend himself when he didn't do everything possible to prevent the outbreak." "We have to do everything possible to try to reduce the risk," Koch said, "The lesson to others from the Dutch experience is to be prepared."

posted by Orange @ 11:03 PM