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Hong Kong Doctors Make Important Discoveries as They Battle SARS - 2003-06-10

Just three months after Severe Acute Respiratory Syndrome struck Hong Kong, doctors and scientists have developed a number of treatments for patients suffering from the serious pneumonia brought on by the illness. Early discoveries have influenced treatment and the direction of research on SARS.

When a Hong Kong hospital received its first few cases of Severe Acute Respiratory Syndrome in early March, medical experts almost immediately began to suspect a new disease was at hand.

By mid-March, the intensive care unit of one of the city's public hospitals had a sudden influx of patients with flu-like symptoms. In addition to high fever, patients all seemed to suffer serious breathing problems.

"On the 14th of March things changed," said David Chan, a senior nurse in the ICU unit of the Prince of Wales Hospital. "We received a message from the hospital that there were a large number of patients with pneumonia and might need ICU admission.... During that time it was really chaotic because we did not have adequate manpower resources and we had no experience in tackling this new type of atypical pneumonia."

SARS patients develop what is called atypical pneumonia, which is caused by a virus, not a bacterial infection, which meant that antibiotics did not help them.

Doctors determined that patients were not infected with an influenza virus such as the "bird flu," a virus originating in chickens that has killed eight people in Hong Kong since 1997.

By March 27, microbiologists from Hong Kong University declared that the coronavirus, which is similar to the one that causes the common cold, was found in many tissue samples taken from SARS victims.

Doctors also discovered that the body's own reaction to the virus complicated treatment.

"It is clear that within a few days you do get an antibody response to the virus, but there is some suggestion that the immune response itself may be aggravating the disease process," said Malik Peiris, a microbiologist at Hong Kong University. "So it is possibly the virus together with the body's immune response that is responsible for the disease." An anti-viral drug called Ribavirin was given to stop the virus from replicating. Steroids were also given to suppress the hyperactive immune response. According to initial reports, this combination helped roughly 80 percent of patients.

Dr. Peiris explained that the steroids were used after tests revealed it was not mucus obstructing patients' breathing. Instead it was the body's immune response that caused lung tissue to swell, impairing its ability to absorb oxygen.

But when steroids failed to bring down the swelling in many patients, health care workers turned to artificial respirators to help patients breath.

The respirators required a doctor and several assistants to place a tube down a patient's windpipe.

As ICU nurse David Chan explained, the procedure is risky for both patient and staff. "During the intubations, the patients' sputum and tracheal secretions will eject out to the doctor and all the nurses around, so the chance of getting infection is very high," he said.

Since the start of the outbreak, doctors have adjusted their treatments for SARS, and now several antiviral drugs are used instead of just Ribavirin.

Doctors have also experimented with using blood serum containing antibodies from recovered SARS patients to treat those in critical condition. This treatment, which has appeared successful in some patients, is risky as blood serum can carry other diseases.

Dr. K.Y. Yeun, who heads Hong Kong University's microbiology department, says that while the elderly and patients with chronic ailments are at a higher risk of complications and even death, the majority of SARS victims are able to fight the disease on their own. "In around more than 50 to 60 percent of patients you actually do not need to give much treatment, the patient may survive improve," Dr. Yeun said. SARS patients, however, still must be hospitalized to treat fever and to prevent complications. Also, because the disease is infectious, medical experts say SARS patients should be isolated from other people.

Dr. Yeun said the best way of dealing with SARS will be to prevent it through vaccines. His team is already working on one that could eventually protect wild animals, where the disease is through to have originated, or even people.

This work is encouraged by the fact that animal vaccines to fight other coronaviruses are already available.

Drugs developed to fight AIDS have also been modified to fight the new coronavirus and have shown some success in test tube experiments. Researchers say, however, it could be some time before those drugs are tested on SARS patients.