Experienced flu pandemic watchers are familiar with Dr. Robert Webster, one of the foremost experts on influenza. When H5N1 started killing people, he was among the strongest voices arguing for increasing our efforts at preparedness. Recently, he was interviewed by Mark Honigsbaum at the Guardian. The whole article is worth reading, but here are few excerpts:
“I haven’t seen the film [Contagion] yet but bird flu is the real killer lurking in the shadows,” says Robert Webster, the world’s pre-eminent expert on bird flu, when I catch up with him en route from Oxford to Malta where he has back-to-back influenza conferences. “Nature has already shown us that there is a virus out there that kills 50% of the people it infects. We ignore it at our peril.”
…Webster insists, the threat from H5N1 has not gone away. On the contrary, if the latest the scientific data are to be believed, a new “mutant” strain of the virus, codenamed 2.3.2., has already moved from China and Vietnam to central Asia and eastern Europe, spread by migratory waterfowl.
Meanwhile, in H5N1 “hotspots” such as Egypt, where another variant is endemic in the poultry industry, the virus continues to kill people in significant numbers.
As Webster told an international gathering of flu experts at St Hilda’s College, Oxford, earlier this month: “Highly pathogenic H5N1 avian influenza appears to be spreading into Eurasia again, most likely carried by wild bird migrations. It’s only a matter of time before it comes to the Americas.”
The most recent reassortment event was in 2009, when a virus distantly related to the 1918 pandemic strain caused a worldwide alert, triggering the activation of international pandemic response plans and the production of billions of pounds’ worth of drugs and vaccines.
Scientists are still uncertain what prompted the reassortment and why Mexico was the centre – H1N1 was what scientists call a “triple reassortant”, containing genes from a human flu, and genes from both north American and Eurasian strains of swine flu.
Despite having invested millions in disease surveillance since the 1990s, Webster says the virus caught flu-watchers with their “pants down”. “In 2009, we were focused on H5N1. We just did not imagine that a variant of H1N1 would suddenly appear because the virus had been stable for years. It was in its monogamous phase. The view was that it couldn’t mate with other viruses.”
Since 2003, H5N1 has infected 565 people and killed 331, a mortality rate of close to 60%. It has also killed or forced the culling of more than 400 million domestic poultry and cost an estimated $20bn.
“What people don’t appreciate is that H5N1 has already been the cause of a chicken apocalypse. Once it learns to go human to human there’ll be no stopping the damn thing.”