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Keep Cats Away from Bird Flu Areas, U.N. Agency Says
February 09, 2007 — By Reuters
ROME -- Cats should be kept away from areas affected by the deadly H5N1 bird flu virus as they can pick up and spread the disease, the United Nations' Food and Agriculture Organisation (FAO) said on Thursday.
Cats at infected farms should be kept indoors, the agency said, as evidence from Indonesia and other countries showed they could catch bird flu from eating infected poultry or wild birds.
The worst fear is that cats could become a host for the virus where it could mutate into a form that may cause a human pandemic, the FAO said.
"Cats could act as intermediary hosts in the spread of the H5N1 virus between species," said FAO's Assistant Director-General Alexander Mueller.
"(Virus) growth in cats might help the H5N1 virus to adapt into a more highly infectious strain that could spark an influenza pandemic."
An outbreak of H5N1 in eastern England last weekend has led several countries to ban poultry exports from Britain which had not been affected by the virus before.
More than 30 countries have reported outbreaks in the past year, in most cases involving wild birds such as swans. Cats have been infected in Thailand, Iraq, Russia, the European Union and Turkey, FAO said.
Bird flu remains essentially an animal disease but has killed 166 people since it re-emerged in Asia in 2003. Almost all the victims have become infected after contact with sick birds.
Sydney Morning Herald
Face masks offer little more than solace
May 6th, 2007
Face masks may do little to prevent infection during an influenza pandemic, but wearing them might help comfort people in crowds, the US Centers for Disease Control and Prevention says.
And people who must care for someone else who is sick during a pandemic should wear a respirator - a specially designed, form-fitting mask, the CDC said.
It admitted that no one has done the research to show what good, if any, a surgical-style mask would do in stopping the spread of a virus.
Experts say a flu pandemic is inevitable. No one can saywhen it will come, or what strain of virus, but there were three flu pandemics in the last century.
The chief suspect is the H5N1 avian flu virus infectingflocks of birds across Asia, parts of Europe and Africa. Itrarely infects people but has killed at least 172 of the 291 people whose infection was confirmed by the World Health Organisation.
If it develops the ability to pass easily from one person to another, it would infect tens of millions of people and could kill millions, WHO says. A good vaccine would take months to manufacture.
Many experts have been asking questions about whether masks might help people protect themselves and might be worth stockpiling now.
The CDC's answer? Maybe.
"We also know that many people may choose to use masks for an extra margin of protection even if there is no proof of their effectiveness," CDC director Dr Julie Gerberding told reporters.
"If people are not able to avoid crowded places, large gatherings or are caring for people who are ill, using a face mask or a respirator correctly and consistently could help protect people and reduce the spread of pandemic influenza."
Other measures already recommended by the CDC and WHO include hand washing, staying away from other people and discouraging crowds.
Some experts have argued that wearing a face mask might give people a false sense of security.
Face masks might be useful in the following instances, the CDC said:
- If people have the flu and think they might have close contact with other people - within about 2 metres.
- If they live with someone who has the flu symptoms or will be spending time in a crowded public place and thus may be in close contact with infected people.
- If people must be in a crowd.
- People should use a respirator mask if they must be in close contract with someone who is ill.
"Face masks are not designed to protect people from breathing in very small particles, such as viruses," said Dr Michael Bell, an infection control expert at CDC.
"Rather, face masks help stop potentially infectious droplets from being spread by the person wearing them. They also keep splashes or sprays from coughs and sneezes from reaching the mouth and nose of the person wearing the facemask."
© 2007 Reuters
Sydney Morning Herald
H5N1 virus 'can pass from mum to child'
September 28, 2007
The H5N1 bird flu virus can pass through a pregnant woman's placenta to infect the foetus, researchers reported.
They also found evidence of what doctors had long suspected - that the virus not only affects the lungs, but passes throughout the body into the gastrointestinal tract, the brain, liver and blood cells.
"The work helps us to understand H5N1's high fatality rate, as well as serving as a model for global collaboration in the field of emerging infectious diseases," said Dr Ian Lipkin of Columbia University in New York, who directed the study.
Lipkin and a team at Peking University in Beijing studied tissue taken from two people killed by H5N1 in China - a 24-year-old pregnant woman and a 35-year-old man.
The study is the first to come out of the Infectious Disease Centre at Peking University in Beijing, established after the epidemic of severe acute respiratory syndrome or SARS, a new virus that spread out of China in 2003, killing 800 people and infecting 8,000 before it was stopped.
The centre is now looking at victims of H5N1 avian influenza. The virus mostly infects birds, but it occasionally infects people and has killed 200 out of 328 infected since 2003. Because experts fear it could cause a pandemic that would kill millions, they are studying it in great detail.
Jiang Gu and colleagues at Peking University looked at tissue samples from throughout the bodies of the victims.
They found genetic material from the virus in the lungs, as expected, but also in the brain, the placenta, the intestines, and in immune system cells in the blood and the liver.
The four-month-old foetus, which died with its mother, was also infected, the researchers reported in the Lancet medical journal.
Their findings support the theory of a "cytokine storm" - the idea that the immune system overreacts to the virus in some cases and sends out an overwhelming swarm of signalling chemicals that end up killing the patient.
"Many people have talked about cytokine storm," Lipkin said in a telephone interview.
"Here the lung findings are that the amount of damage appears to be disproportional to the number of cells that were infected. This supports the hypothesis that there might be indirect methods of damage."
They also found evidence the virus had damaged immune cells including macrophages, which they said suggests the virus not only overstimulates parts of the immune system but can also suppress other parts.
Previous studies of H5N1 victims have produced evidence the virus may have evaded their immune systems' defences by suppressing them.
The researchers noted that no one had thought human influenza could cross the placenta and affect unborn babies.
"But there just isn't that much information," Lipkin said.
© 2007 Reuters
Sydney Morning Herald
Bird flu becoming riskier for humans
October 5, 2007
The H5N1 bird flu virus has mutated to infect people more easily, although it still has not transformed into a pandemic strain, researchers say.
The changes are worrying, said Dr Yoshihiro Kawaoka of the University of Wisconsin-Madison.
"We have identified a specific change that could make bird flu grow in the upper respiratory tract of humans," said Kawaoka, who led the study.
"The viruses that are circulating in Africa and Europe are the ones closest to becoming a human virus," Kawaoka said.
Recent samples of virus taken from birds in Africa and Europe all carry the mutation, Kawaoka and colleagues report in the Public Library of Science journal PLoS Pathogens.
"I don't like to scare the public, because they cannot do very much. But at the same time it is important to the scientific community to understand what is happening," Kawaoka said in a telephone interview.
The H5N1 avian flu virus, which mostly infects birds, has since 2003 infected 329 people in 12 countries, killing 201 of them. It very rarely passes from one person to another, but if it acquires the ability to do so easily, it likely
will cause a global epidemic.
All flu viruses evolve constantly and scientists have some ideas about what mutations are needed to change a virus from one that infects birds easily to one more comfortable in humans.
Birds usually have a body temperature of 41 degrees Celsius, and humans are 37 degrees Celsius. The human nose and throat, where flu viruses usually enter, is usually around 33 degrees Celsius.
"So usually the bird flu doesn't grow well in the nose or throat of humans," Kawaoka said. This particular mutation allows H5N1 to live well in the cooler temperatures of the human upper respiratory tract.
H5N1 caused its first mass die-off among wild waterfowl in 2005 at Qinghai Lake in central China, where hundreds of thousands of migratory birds congregate. That strain of the virus was carried across Asia to Africa and Europe by
migrating birds. Its descendants carry the mutation, Kawaoka said. "So the viruses circulating in Europe and Africa, they all have this mutation. So they are the ones that are closer to human-like flu," Kawaoka said.
Luckily, they do not carry other mutations, he said.
"Clearly there are more mutations that are needed. We don't know how many mutations are needed for them to become pandemic strains."
© 2007 Reuters
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