Avian Flu - What we need to know

Tracking bills to model the spread of viruses

Using a popular internet game that traces the travels of dollar bills, scientists have unveiled statistical laws of human travel in the United States, and developed a mathematical description that can be used to model the spread of infectious disease in this country. This model is considered a breakthrough in the field.

Source, via Pablo Halkyard. It is unclear to me how much "new" information this would add to existing epidemiological models. Leave your thoughts in the comments section if you know more.

Migratory birds and avian flu

The debate on whether wild birds help spread the H5N1 virus around the world has made many headlines in recent days. Some have made arguments such as this one:

Millions of waterbirds flew already from Asia to the Middle East and Africa. However, the flu didn't travel with them, so far. An explanation for this might be that contaminated birds die quickly. The global trade in millions of chickens and other poultry might be a much bigger risk. Wetlands International calls for additional attention for the risks of the bio-industry and the global trade of poultry.

Revere at Effect Measure evaluates this argument critically.

I find it extremely unlikely that the virus is spread mainly through poultry trade. In Romania the first cases of bird flu were detected in remote villages that trade very little with anyone. The villages were in the Danube delta, a huge wetland packed with migratory birds. We saw similar stories in Russia,  Turkey, or Qinghai Lake. Migratory birds were the likely vectors in all these cases.

Thai authorities unsure how latest victim contacted H5N1

Last Friday Thailand announced a 5 year old boy was the country's latest H5N1 victim. Here is a brief update on the investigation that followed the boy's death:

27 people who had contact with lad in Nakhon Nayok test ‘negative’. Initial tests on people who had been in contact with the country’s latest human case of bird flu have cooled fears of a human-to-human outbreak, though it remains unclear how the infection was transmitted.

None of the blood samples drawn from people who had contact with the 5-year-old boy from Nakhon Nayok who died last week have tested positive.

[...] Meanwhile, the Livestock Development Department said it would track the cause of the boy’s infection. It found no signs of the virus in the poultry near the victim’s house.

“It looks frightening. The chicken didn’t die but the boy did. This is an issue that needs investigation and clear answers,” Yukol Limlaemgthong, the department’s director-general, said.

Sompong said pigeons might be the source of the infection, dismissing the possibility of human-to-human transmission.

There were many pigeons around the boy’s house and the bird-flu virus might have been present in the birds’ faeces, he said.

The article is from The Nation.

Smuggling exotic birds

Read one account from the CDC on how a pair of crested hawk-eagles was smuggled from Thailand into Belgium in 2004. Thanks to Sasha for the link.

How did bird flu get to Russia?

The typical story is that wild migratory birds carried the flu from China. A new article challenges this view, claiming that "the timing and distribution of the reported spread of H5N1 ... does not fit any known migratory pattern for any species". The alternative theory:

The article argues instead that the disease was more likely spread by the unrestricted movement of domesticated poultry, or even illegal trade in fighting cocks.

This view is also supported by research by Dennis Alexander in the journal Veterinary Microbiology. He argues that although wild birds may carry many types of flu and may infect agricultural birds, it is human movement of birds through farming, slaughter and trade that accelerates its spread.

Read the entire controversial piece here.

The spread of bird flu to Europe

According to UN officials the Balkans may be the gateway for bird flu in Europe:

Millions of birds migrate each year to Black Sea neighbours Romania and Bulgaria for the milder winter climate, making the area a potential gateway to central Europe for the bird flu virus, which has already swept into Russia from southeast Asia.

[...] "Knowing the flyways and the bird species that use them, there is a high likelihood that the virus will continue to spread as it has so far," Jutzi, Director of the Animal and Production and Health Division of the U.N.'s Food and Agriculture Organisation, told Reuters.

"Particularly in the southeastern part of the Balkans, given that these flyways go down there ... It is quite probable in the future and is a major concern for us."

WHO to stockpile Tamiflu

BANGKOK, Thailand (AP) - The head of the UN health agency said Tuesday negotiations are underway to build a stockpile of avian-flu fighting drugs for Southeast Asia to help guard against a potential global flu pandemic.

Dr. Lee Jong-wook said the World Health Organization hopes to initially acquire one million doses of the anti-viral Tamiflu, which is the only drug known to be effective against avian influenza in humans. He said talks are underway with other countries and Swiss drug manufacturer Hoffmann-La Roche Inc. to allow the medicine to be distributed to poor countries for free or at highly discounted rates.

Currently WHO has only enough Tamiflu to treat about 125,000 people, he said.

"Clearly for us and for others this is very important; to deal with the problem at the source," he told reporters in Bangkok where he was attending a global conference on health promotion. "WHO has a very limited stock. We want to increase the stockpile and we would like to deploy this to countries in this region."

Lee also warned that it makes no sense for wealthy countries to horde large volumes of either the drug Tamiflu or an experimental vaccine that has recently shown promise in humans.

He said the best way to control the virus if it begins spreading among humans is to hit it hard at the source, with wealthier countries sharing their drugs. The United States already has enough Tamiflu to treat 2.3 million people and is working to acquire more, while Britain, France, Finland, Norway and New Zealand are placing orders that would cover between 20 per cent and 40 per cent of their populations.

The story is from Canada.com. The claim that early decisive action can stop bird flu if its caught early on is not new. Regardless of the controversy surrounding the idea, the decision by the WHO to have its own stockpile ready for rapid deployment in East Asia is welcome. The call for rich countries to stop their "hoarding" is a bit strange. Large orders from these countries will likely increase production capacity, surely a good thing in the medium to long run.

The latest media coverage on bird flu

There has been quite a bit of talk lately both in the press and the blogosphere about what can be done to fight bird flu. Early this week there were a number of stories claiming that bird flu could be stopped if it were detected early enough and local authorities responded immediately. The talk revolved around computer simulated models of bird flu. Randall Parker offers a great review of the discussion at FuturePundit, and Effect Measure argues that the idea that bird flu could be stopped is a nothing but a mirage.

A second set of stories came out today, reporting advances in vaccine development. The New York Times and the Washington Post, for example, ran articles on this story today. From the NYT:

The new vaccine for avian flu is derived from a strain that Dr. Robert G. Webster, an internationally known influenza expert, helped isolate from a human case in Vietnam. Dr. Webster is on the faculty of St. Jude Children's Research Hospital in Memphis, and his work is supported in part by the National Institute of Allergy and Infectious Diseases.

Because the A(H5N1) strain of avian flu is lethal for chickens and so could not be grown in eggs, Dr. Webster had to use a technique known as reverse genetics to remove the gene that made the virus deadly. This altered virus was used by Sanofi-Pasteur, a French vaccine company, to produce the vaccine in chicken eggs.

Effect Measure offers the best coverage of the story. Many problems remain with this experimental vaccine: more extensive clinical trials are needed; currently there is not enough production capacity; the virus can mutate and make the vaccine ineffective. Still, a (partially) effective vaccine is surely a positive development.

Will bird flu soon spread to Europe and Australia?

In mid-August, the [avian flu] survivors will start returning to their winter ranges, which stretch from eastern Europe to Australia and Alaska, and overlap with the ranges of other migrants. Mundkur cautions that it is not known how many birds from Qinghai Lake migrate to the farthest reaches of their species’s known ranges. But if some birds carrying the virus remain healthy enough to migrate, the disease could spread far and wide...

What is not clear is whether the Qinghai virus is any more deadly to wild birds than the other H5N1 variants that have killed wild birds. The Qinghai outbreak might merely be the first time that H5N1 has had the opportunity to infect such a large number of wild fowl.

“Any susceptible migrant could pick up the virus and die in the wild without being noticed,” says Mundkur. “It is only because the birds were congregating in a place that is visited, that the mass die-off was reported at Qinghai.”

Nor is it known if the Qinghai virus could kill humans. It does have a mutation associated with increased deadliness in mammals – Gao found that it kills all mice infected with it in four days – but this mutation may not be enough to make the virus dangerous for humans.

What is certain is that if the virus spreads to other countries, it will decimate poultry industries. The sequence also shows that H5N1 viruses in Asia are swapping genes – which could give rise to a virus capable of causing a human pandemic.

Here is the full story.

WHO estimates $150 million needed to combat bird flu

The funds are in addition to the 100 mln usd that United Nations experts meeting here this week said it will cost to combat avian influenza among animals over the next decade.

'This is a ballpark figure subject to changes, because the situation is very fluid,' Omi [WHO Pacific region director] told reporters.

The extra 150 mln dollars will cover the 'human aspect' of bird flu, including a response to any outbreak and providing vaccines to try to ward off a pandemic, he said of the figure finalized here this week by WHO officials.

It will also be spent on boosting the resources and skills of countries affected by bird flu, including improving laboratories, developing vaccines, monitoring and public education.

A donor country fundraising conference is expected later in the year. To this date under $10 million has been pledged. The US was expected to contribute some $25 million. Read the full story at Forbes.com.