SARS investigators closing in on first person infected in Asia

China admits WHO team

work on vaccine begins

April 05, 2003|By Michael Stroh | Michael Stroh,SUN STAFF

Investigators are making headway in tracing the origins of the mystery illness SARS, identifying a Chinese man who might have been its first victim and accumulating evidence that the disease was acquired from an animal.

Scientists say that each new scrap of data about severe acute respiratory syndrome puts public health officials a step closer to answering the question uppermost in their minds: when will the epidemic end?

"The stakes are high. And the outcome cannot be predicted," Julie L. Gerberding, director of the Centers for Disease Control and Prevention, wrote in an editorial for the New England Journal of Medicine.

CDC officials said yesterday that the number of suspected U.S. cases continued to climb. There are now 115 cases in 29 states, but no deaths. The worldwide SARS tally stands at 2,353 cases in 16 countries, according to the WHO Web site. The disease has claimed the lives of 84 people, mostly in China.

After weeks of withering criticism that it badly mishandled and tried to cover up the emerging epidemic, the Chinese government made a rare public apology yesterday for not being more forthright.

"Our medical departments and our mass media suffered poor coordination," said Li Liming, director of the Chinese Center for Disease Control. "Today, we apologize to everyone."

The government permitted a four-member World Health Organization team to start collecting disease data yesterday in Guangdong province, where the SARS outbreak is thought to have originated last fall. The team is focusing its initial efforts on Foshan, an industrial city in the southern part of the province where some of the earliest SARS cases were reported.

Father of four

Investigators said they were particularly eager to interview a Foshan father of four who is thought to be the first person infected by the disease, which causes fever, cough and shortness of breath.

Authorities provided few details about the man, other than that he was released from the hospital in January and is suspected of having passed the virus to four other people.

Strangely, however, none was in his own family - a finding that could turn out to be an important clue to the behavior of the disease, WHO officials said.

Another puzzling discovery in Foshan is that five of the 24 SARS victims there appear to have contracted the disease indirectly, perhaps by touching something tainted by a sick person's mucus or saliva.

If that proves accurate, it would be one more seemingly contradictory revelation to emerge about SARS. It's still unclear how it spreads. Most evidence points to airborne droplets released when someone nearby coughs or sneezes, though there is speculation it could be transmitted through ventilation or water systems.

New strain of virus

It's also not clear what causes it, though sophisticated tests in eight laboratories around the world, including the CDC, have strongly implicated the coronavirus family, which also causes the common cold.

DNA tests, however, have shows that whatever is causing SARS appears to be a completely new and unfamiliar strain of the virus.

Chinese investigators, meanwhile, have revealed new evidence that the disease-causing agent jumped to humans from fowl, an occurrence known as zoonosis.

Bi Shengli, vice director for viral diseases at the Chinese Center for Disease Control and Prevention, told the South China Morning Post that the first SARS victims in Guangdong appear to have been bird venders, chefs and others who had been in close contact with chickens, ducks, pigeons and owls. The group might also include some people who eat exotic fowl.

"We will explore further if the disease was passed to human beings from wild animals. You know, Guangdong people like eating exotic animals, and I don't find it a healthy practice," he told the newspaper.

Animals are a well-known reservoir of human disease. Influenza, for example, typically originates in migratory birds, whose virus-loaded droppings infect ducks, which pass the virus to the pigs that transmit it to people. Coronavirus infects those animals, as well as many others.

Robert Webster, an influenza expert at the St. Jude Children's Research Hospital in Memphis, says it's not surprising that SARS seems to have emerged in southern China, where it is common to find households with ducks, chickens and pigs.

The Asian flu of 1957 and the Hong Kong flu of 1968, the last two major influenza pandemics to sweep the globe, were both traced to the region.

Specialists who study epidemics of influenza and other diseases say they might offer some insight into how SARS will progress.

In textbooks, epidemics often play out in a pattern that looks like a bell curve, a discovery made by British statistician William Farr studying cholera outbreaks in 19th-century London.

The key to how quickly the disease takes off - and how steeply the curve rises - is what epidemiologists call a disease's "reproductive number," the average number of people someone with the disease is able to infect.

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