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China has found two more cases of a new strain of bird flu and one of the victims has died, state media said on Wednesday, bringing the number of cases to nine.

The new death comes as scientists struggle to identify the source of the virus H7N9 infection.  Many who have examined the genetics of the virus believe it could actually be spread silently between birds, without them showing any signs of symptoms.  However, officials do not know for sure if those infected with H7N9 actually contracted the virus from birds or any other animals.

So far, the Agriculture Ministry said it had yet to find any animals infected with H7N9, but added it was possible it had been brought to China by migratory birds.  If the virus is spread from birds to humans, scientists and other officials are worried about the potential for a H7N9 pandemic, as birds are difficult to contain.

The Food and Agricultural Organization (FAO) of the United Nations said, however, there are many precautions they can take to stop the spread of the virus from birds to humans, if it is determined that is the way H7N9 is spreading.

“Although birds are not easily contained, we are able to separate species of birds,” Juan Lubroth, doctor and chief veterinary officer of FAO, told FoxNews.com.  “If we see the carriers are ducks, we separate ducks from chickens.  I the carriers are wildlife, we are able to change our rearing practices with nets so they won’t enter certain facilities.  There are things you can do. I can’t say it’s easy or free, but it’s an investment to protect people’s lives and commerce.”

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The FAO has many projects up and running in China that analyze human-animal interface, to pick up novel pathogens in that may affect human health.  Lubroth said H7N9 is particularly worrisome because scientists have never seen the virus behave this way in humans before.

“Characterized as low pathogenicity in poultry, so that makes detection a little harder for veterinary services,” Lubroth said.  “We do not have what we had with H5N1, where chickens were dying off.  You don’t have that red flag, such as a dramatic event, which would trigger an owner to call veterinary services to see what is happening.”

A 38-year old cook became ill early last month while working in the province of Jiangsu, where five of the other cases were found. He died in hospital in Hangzhou city on March 27, the Xinhua news agency reported. Samples tested positive for the new H7N9 strain on Wednesday.

The second patient, also in Hangzhou, is a 67-year old who is under treatment. Xinhua said no connection between the two cases had been discovered, and no one in close contact with either patient had developed any flu-like symptoms.

Of the seven other cases of the new strain, two have died, both in the business hub of Shanghai The other five are in a critical condition in hospital in Nanjing.

Shanghai, Nanjing and Hangzhou are all close to each other in eastern China.

The World Health Organization said on Monday that the first three cases had shown no evidence of human-to-human transmission, but that there were questions about the source of the infection and the mode of transmission.

One of the world's top flu experts, Ab Osterhaus, based at the Erasmus Medical Center in The Netherlands, is concerned about some of the sequence's genetic mutations.

"The virus has to a certain extent already adapted to mammalian species and to humans, so from that point of view it's worrisome," he told Reuters in a telephone interview. "Really we should keep a very close eye on this."

China has stepped up its alert level since the cases came to light and has said it is being transparent in dealing with the outbreak.

China has a checkered record when it comes to tackling bad news, which has been known to be covered up by officials fearing it may attract unwanted attention from superiors and damage promotion prospects.

In 2003, authorities initially tried to cover up an epidemic of Severe Acute Respiratory Syndrome, which emerged in China and killed about a tenth of the 8,000 people it infected worldwide.

Reuters contributed to this report.