Avian Flu - What we need to know

The risks of eating food contaminated with bird flu

Read Effect Measure for a good analysis.

The 1951 mystery flu

Revere comments on a fascinating article at Effect Measure. The bottom line: we have a very poor understanding of flu viruses.

Using horse antibodies to fight bird flu

Chinese scientists have produced antibodies in horses that are an effective treatment for bird flu – at least in mice.

Jiahai Lu at Sun Yat-sen University in Guangzhou and colleagues repeatedly inoculated horses with a chicken vaccine against H5N1 bird flu to make them produce antibodies.

They then collected the horses’ blood, separated out the antibodies and split them to make them less likely to cause an allergic reaction when injected into a human. When they injected mice with a tenth of a milligram of these antibodies 24 hours after they had been given an otherwise lethal dose of H5N1, all the mice lived.

In theory, such antibodies could be made quickly against a pandemic strain of H5N1, potentially saving many lives and limiting the spread of the virus. The trouble is that most drug companies have stopped making antibodies this way.

This is because keeping horses is expensive and until now the markets for antiserum have been in poor countries and offer low financial returns. In addition, animal rights campaigners object to the technique.

Companies have instead invested in making modern, monoclonal antibodies using cell cultures. "It would be complex and expensive for a company to hugely scale up its monoclonal production to treat whole populations rather than a few people,” says David Fedson, founder of the vaccine industry’s pandemic task force.

Source.

WSJ piece on Henry Niman

Most of the regular readers have no doubt checked out Henry Niman's blog Recombinomics at some point or another. Nicholas Zamiska now gives you an in depth look at the person behind the blog in his latest WSJ article.

Why bird flu does not spread easily from person to person

This week, two research groups are independently reporting results that help explain why the H5N1 avian influenza virus is so lethal to humans but so difficult to spread. Unlike human influenza viruses, the teams report, H5N1 preferentially infects cells in the lower respiratory tract. Residing deep in the airways, the virus is not easily expelled by coughing and sneezing, the usual route of spread. The results "explain a lot of the mysteries" surrounding H5N1, says K. Y. Yuen, a virologist at the University of Hong Kong.

[...] One team, led by Yoshihiro Kawaoka of the University of Wisconsin, Madison, tested various tissues of the human respiratory tract for receptors to which the virus can bind. Human flu viruses preferentially bind to what are known as α 2,6 galactose receptors, which populate the human respiratory tract from the nose to the lungs. Avian viruses prefer α 2,3 galactose receptors, which are common in birds but were thought to be nearly absent in humans. Using marker molecules that bind to one receptor or the other, the team found that humans also have α 2,3 galactose receptors, but only in and around the alveoli, structures deep in the lungs where oxygen is passed to the blood. They describe their findings in the 23 March issue of Nature.

The second team, led by pathologist Thijs Kuiken of Erasmus University in Rotterdam, the Netherlands, used a more direct technique to show that H5N1 readily binds to alveoli but not to tissues higher up in the respiratory tract. Kuiken, whose team will publish its findings online tomorrow in Science, notes that this pattern is consistent with autopsies that have shown heavy damage to the lungs but little involvement of the upper respiratory tract. Among experimental animals, the team reports, cats and ferrets more closely match the human pattern of infection than do mice and macaques. "This is an important factor to consider when planning experiments" to understand the pathology of H5N1, says Kuiken.

Yuen notes that the findings also explain clinical anomalies such as why nasal swabs of H5N1 patients are less reliable than throat swabs in detecting the virus. And they suggest that clinicians need to exercise particular care when performing procedures, such as intubation, that might give the virus a route out of a patient's lungs.

From ScienceNOW Daily News. The Washington Post has a slightly different version of the same story.

Addendum: Effect Measure offers excellent comentary, as usual.

More on the WHO and bird flu samples

The World Health Organization is discussing whether to expand access to its private bird-flu database, as pressure mounts on the United Nations agency to do so as a way to spur wider research on the virus. Meanwhile, in an apparent effort to increase the amount of data available to scientists, the WHO will ask its 192 member states to adopt a resolution in May that includes a pledge to share virus data, Margaret Chan, the WHO's pandemic-flu chief, said yesterday. It isn't yet clear if the resolution will seek to make the data publicly accessible. In a related development, China is set to share a large number of virus samples that it has withheld for more than half a year, a WHO official said.

That is from and article by Nicholas Zamiska, published in today's WSJ. Read more at Effect Measure.

Bird flu virus now in two distinct strains

The H5N1 virus responsible for the current virulent strain of bird flu has evolved into two genetically distinct strains, US scientists have confirmed.

They fear this could increase the risk to humans - and complicate the search for an effective vaccine.

The US team analysed more than 300 H5N1 samples taken from infected birds and people between 2003 and summer 2005.

Details were presented to the International Conference on Emerging Infectious Diseases in Atlanta.

Full story at BBC.

The H5N1 genome

Last Friday the journal Science published a paper with some preliminary findings.

The WHO's bird flu sample sharing policy

Even as the World Health Organization presses China and other countries to share bird-flu data for the public good, the WHO itself runs a database limited to a select group of scientists and containing a massive trove of data -- some 2,300 genetic sequences of the virus, around a third of the world's known sequences, according to two people familiar with the database's contents. Any one of those sequences could hold clues to an effective human vaccine or drugs that could kill the virus, or help scientists determine how great a threat it poses.

Now, a lone Italian researcher has cast a harsh spotlight on the WHO's system, suggesting that it places academic pride over public health – and snubbing it by posting prized bird-flu data in plain view.

Ilaria Capua, a 39-year-old Italian veterinarian working on avian influenza in a government lab, last month received a sample of the virus in the mail from Nigerian health authorities. The virus had just attacked birds in Nigeria, the first confirmed case of the disease in Africa. The sample was something of a prize, a chance to study a specimen and explore how it spread from its stronghold in Asia.

Within days of isolating the virus, Dr. Capua says, she got an offer from a senior scientist at the WHO in Geneva, whom she declined to name, to enter her finding in the closed system. She could submit the virus's genetic information, or sequence, to the database. In exchange, she would be given the password to the WHO's massive stash of data. A spokesman for the WHO confirmed that the offer was made.

Instead, Dr. Capua posted the gene sequence in a public database accessible on the Internet. She also sent a letter on Feb. 16 to around 50 of her colleagues urging them to do the same with their bird-flu samples.

"If I had agreed" to the WHO's request, she said in an interview, "it would have been another secret sequence."

The WHO, normally an outspoken advocate of transparency, says it limits access to the database so scientists and governments will share bird-flu data they might otherwise hoard to further their own research. Scientists with access to the system can collaborate with each other but must agree not to publish results without prior consultation. Michael Perdue, a leading scientist at the WHO in Geneva, says the system has proven to be a useful compromise, because some sharing is better than none.

The quote is from a WSJ article by Nicholas Zamiska published today. Here is his earlier story on China's samples.

Recombinomics warns of likely change in H5N1 virus

Here is the link. The discussion is techincal and I do not feel qualified to comment. If anyone knows more about Henry's "patent-pending approach" feel free to share your thoughts.