An international team is turning up possible clues to the spread of severe acute respiratory syndrome as it tries to follow the disease's tracks across the bustling landscape of southern China.
Chinese experts in hard-hit Guangdong province told the scientists they have found a rare form of airborne chlamydia in some of their SARS patients, raising the possibility that more than one germ may be involved. Other Chinese cases suggest the disease might be passed by touching something tainted by a sick person's mucous or saliva.
SARS continued to spread Saturday even as health officials stepped up their efforts to contain the disease. New cases were reported in Indonesia and Sri Lanka, while Hong Kong reported more three deaths and Malaysia announced its first.
In Hong Kong, workers covered head to toe in protective gear captured rats and roaches at an apartment complex where at least 250 people were infected. They also rounded up pets — eight dogs, 14 cats, two hamsters and two turtles — after a cat was found to carry a coronavirus.
Coronaviruses are commonly found in animals, but microbiologists believe SARS is caused by a new form of coronavirus. Scientists are trying to determine if animals somehow carried the virus through the complex.
China responded Saturday to criticism of its handling of the outbreak by promising to create a disease warning system and keep its public better informed.
Vice Premier Wu Yi called for establishment of such a system "with emphasis placed on a public health information system," the official Xinhua News Agency and official newspapers said.
Wu's comments were the highest-level response yet to demands that the reflexively secretive communist government change how it handles such outbreaks. It followed an extraordinary apology Friday by the country's top disease-prevention official amid complaints that China released information too slowly.
On Saturday, the World Health Organization team met experts at Zhongshan University who collected hundreds of specimens of blood, lung fluid and other materials from people who died of SARS and those who recovered, said Dr. Robert Breiman, the team leader.
The team wants to map the spread of the disease in Guangdong. WHO suggested comparing samples to find out whether those who died fell victim to a combination of viruses or bacteria, not just one strain, Breiman said.
Chinese authorities say they found a rare, airborne form of chlamydia — a virus usually transmitted through sexual contact — in many who died.
"It raises the question of, if you have one pathogen and you get hit with, say, coronavirus (do) you get a particularly bad disease?" Breiman said. "Or are you more likely to transmit? Do you become what we call a `super spreader'?"
The WHO specialists say a key part of their search will be to draw on knowledge of Chinese experts who know the region and physicians with experience treating SARS patients.
SARS has killed at least 82 people in Asia and Canada and sickened at least 2,200 in more than a dozen nations. Mainland China accounts for more than half the fatalities.
No cure has been found, though health officials say most sufferers recover with timely hospital care. Symptoms include high fever, aches, dry cough and shortness of breath.
On Friday, the WHO team visited Foshan, an industrial city in Guangdong where provincial officials say the world's first known SARS case occurred in November. Guangdong accounts for 40 of the 46 deaths reported by China.
The WHO team said a key to the disease's speedy — yet seemingly erratic — transmission could lie in how the apparent first case, an unidentified businessman, passed it to four people without infecting his children. He survived and was released from the hospital in January.
Many of the world's flu strains are traced to Guangdong and farms where people are believed to contract diseases from pigs and ducks.
But the WHO team says most Chinese SARS cases are city dwellers, and Breiman said no link to animals has been established.
"Contact with animals is still being looked into, but nothing convincing one way or the other has come out," he said.
Another important clue that WHO unearthed from data provided by Foshan health authorities: The illness, originally thought to be transmitted primarily through such direct contacts as coughing and sneezing, appears also to be passed indirectly.
Five of the 24 cases in Foshan show no actual "trace of transmission" to others, suggesting that infection can be spread by touching something tainted by a sick person's mucous or saliva, the experts said.
The spread of SARS has disrupted air travel and forced the closure of schools, hospitals and businesses in many countries. Hong Kong's airport authority said 116 flights, one-fifth of all flights to the territory, were canceled on Saturday.