Could China new H7N9 bird flu reaches Boston?

You may have heard about the new bird flu, called H7N9, which has been simmering in eastern China has killed 36 people. Given that Beijing is the second busiest airport in the world, is a reasonable fear that the Chinese flu outbreak could quickly spread if an infected person traveling abroad. Can the flu come to the U.S. and turned into a global pandemic?

Can - but only if the virus spreads easily among humans.

Sometime in early February this year, a middle-aged man who lives in the city of Shanghai to visit live bird markets. He chose chicken vendor who apparently healthy slaughtered on the spot. He took home freshly killed animals, in which he washed, prepared, and cooked.

Within 2 weeks of eating this food, man  body temperature rises to 106 degrees Fahrenheit and he developed chills and coughing up mucus. On February 20, he was admitted to a local hospital, where his lungs failed. A week later, the man died at the hospital from a sudden illness.

But here's what is potentially worrisome. Men from Shanghai do not live alone. Father and sister live in the same house. In mid-February, the two men developed a cough and high fever. A week later, his father also died. His brother, thankfully, improved. Both were found to be infected by avian virus we now call H7N9.

Because all three men lived in the same house - can we assume that the virus can be passed between people? "The investigation by an international scientific team concluded that the evidence so far is not enough to say that the person-to-person transmission has occurred," said Marc Lipsitch, Director of Center for Communicable Disease Dynamics at Harvard School of Public Health.

In short - do not - we can not assume they catch it from one another. Instead, three people may have taken it from a visit to a local poultry market. Buy fresh poultry from the market is not unusual in China, where the stack of flattened several blocks and cages containing birds, ducks, quail, and other animals at close range, providing ample opportunity for viruses to mix and produce new strains, in a process called reassortment. Humans may take new viruses after exposure to these birds, which greatly increased risk during the cutting process, prepare, and cook (but not eat) chicken.

As a result, the Chinese government has been pursuing alleged exposure by covering the poultry market. The result, so far, decent. The epidemic has started to fade - the last known case was reported on May 8. So far, humans do not seem to spread the infection to each other at a detectable level. Even if the infected person boards the plane to the U.S., he is not likely to pass the disease to fellow passengers.

But neither the U.S. nor China CDC has put the guard down. There are alternative ways viruses can leave China than people in on the plane. Because birds are not sick as H7N9 infected humans, they can quietly spread the disease across the country. Some poultry from China were transported to nearby Vietnam. And the virus may be secretly transported by other winged bird that can fly great distances outside of China.

And what of the three people who live in the same house that all fall ill? Even if they visit the bird market, not too likely they do not really capture each other?

It certainly is.