Researchers remain puzzled over how SARS is spreading

Hospital struck by virus traces outbreak to device

April 09, 2003|By Gady A. Epstein | Gady A. Epstein,SUN FOREIGN STAFF

HONG KONG - A month after the World Health Organization issued a global health alert about the lethal new disease known as SARS, medical detectives are still in the middle of a winding, complex investigation into the most basic question: how the virus is being spread.

Relying on educated guesses as much as scientific proof, experts know the answer is essential to helping stem new infections - which are increasing at an alarming rate here and elsewhere in Asia.

In the first Hong Kong hospital struck by severe acute respiratory syndrome, doctors now believe the chief culprit in spreading infection was a device called a nebulizer, which is used to deliver medications into a patient's lungs in the form of a mist. At the Amoy Gardens apartment complex where more than 250 have been infected, investigators suspect that the virus passed through the sewage system, possibly spread by cockroaches.

And at the Metropole Hotel, a 64-year-old Chinese physician appears to have been a so-called "super infector," spreading the virus, probably by coughing or sneezing or contaminating surfaces. He infected guests and visitors but, mysteriously enough, not hotel employees.

The rest of the story may be well known now - 17 countries, more than 2,600 infected, 103 dead, according to the WHO - but what eludes experts is certainty about how the SARS virus is spreading.

"We are still learning about that," said Leo Poon. He is among the Hong Kong researchers who isolated the virus believed to cause SARS - a new form of coronavirus, a family of viruses responsible for the common cold.

In recent days, the virus has shown no signs of slowing down here, with 45 new cases yesterday, bringing the total to 928, with 25 deaths. Doctors and nurses are still getting infected, and perhaps unwittingly sending the virus back into the communities the hospitals serve.

"It's like a bouncing ball, bouncing from the community to the hospital, from the hospital to the community, and from the community back to the hospital," said Lo Wing-lok, an expert in infectious diseases. "We need not only to identify the people. We need to identify the risky environment."

Lo and others here note that while the virus has spread efficiently on its own, many cases can be traced to buildings - like hospitals and Amoy Gardens - that act as "amplifiers," as Lo put it. Health care workers and Amoy Gardens residents infected with the virus account for the majority of those who are sick.

However, Lo said the virus has spread beyond those buildings' walls. "We are beyond the stage that strict quarantine will be really any help," he said.

In addition to transmitting the virus through face-to-face contact or by tainting surfaces such as elevator buttons or stairway railings, doctors here and elsewhere have suggested that infected people who have no symptoms could be passing the disease on to others.

Fears about contracting SARS have disrupted business and tourism here, forced the cancellation of concerts and sports events, and kept many here from shopping in malls or riding the subway. Around the world, fewer people are boarding airplanes because of SARS.

"My concern is with international travel and with the recirculation of air in planes for long distances," said Dr. George A. Pankey, director of infectious disease research at the Ochsner Clinic Foundation in New Orleans. "The longer the trip, the more it's recirculated. And the more someone coughs and puts droplets in the environment, it's common sense that you would have more likelihood of spread."

Doctors believe the best way to block the spread of the disease may be public education about the methods of transmission, much as AIDS education has been a cornerstone of battling the spread of HIV.

But the problem, some doctors here say, is that people are waiting for scientific, proof-positive answers when none may be immediate. "Sometimes the public health deductions can never be proven," said Leung Ping-chung, a medical professor at the Chinese University of Hong Kong who is also a doctor at Prince of Wales Hospital.

"One of the mistakes Hong Kong has made is relying too much on science, because observation short of scientific proof during the prevention period can be important," he said.

Leung said he believes the varying paths the virus has traveled in Hong Kong are a strong indication that more than one pathogen may be infecting patients simultaneously.

Leung noted Chinese doctors' speculation about the role of an airborne form of chlamydia, which was found in a number of patients in China's Guangdong province. "Initially nobody believed it, but if they have seen it after so many examinations, it should not be ignored," he said. "So far, Hong Kong has ignored it. I think it's wrong."

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