The U.N.'s Food and Agriculture Organisation (FAO) has expressed concern the new avian influenza A H7N9 virus could spread outside China and potentially infiltrate the rest of the world.l

"This particular region is land linked and so there is a possibility that if, inadvertently or advertently, somebody moves infected poultry across borders we can anticipate the spread of this virus," Subhash Morzaria, FAO's regional manager of the Emergency Centre for Transboundary Animal Diseases, was quoted by Reuters.

"We are proactively initiating surveillance programmes in neighbouring countries like Myanmar, Laos and Vietnam which border China and are at particular risk and we are trying to understand how the poultry movement has taken place so we can identify more accurately where the risk is going to be," Mr Morzaria.

As of Friday, the new avian influenza A H7N9 has claimed 10 lives in China, while the number of infected has risen to 38.

In a report published by the New England Journal of Medicine, it said that researchers at the Chinese Center for Disease Control and Prevention in Beijing have finally offered details on at least three out of the nine known deaths associated with H7N9 bird flu.

The three victims, an 87-year-old man, a 27-year-old-man, and a 35-year-old woman, all suffered high fever and cough. They developed acute respiratory distress syndrome as their disease progressed. Acute respiratory distress syndrome is a state wherein fluid builds up in the air sacs of the lungs, making breathing and oxygen intake difficult to manage. The eldest H7N9 patient died after 13 days, while the two others, after a week. All received antiviral medications a week after they fell ill.

"Severe avian influenza A (H7N9) infections, characterized by high fever and severe respiratory symptoms, may pose a serious human health risk," the researchers wrote.

Scientists in the US are racing to create a vaccine against the avian influenza A (H7N9) virus, but said doing and manufacturing it is not easy.

In a paper released on Thursday, the U.S. Centers for Disease Control and Prevention said "there are many challenges to making H7N9 vaccines available."

"Vaccines against H7 avian flu viruses that have already been studied haven't produced a strong immune response in humans," CDC flu scientists Timothy Uyeki and Nancy Cox wrote in an article, also published online in the New England Journal of Medicine. In the event of a new vaccine, it would still take months to produce and distribute, they noted.

"This new H7N9 virus hasn't been demonstrated to be transmitted between humans, so from that context we think that the H7N9 virus is not going to be a pandemic like H1N1 strains. These are the early indications," Mr Morzaria said.

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