Fears spread about mystery disease as more fall ill

HONG KONG -- Adding to fears that a deadly flu-like illness is being spread by air travelers, Hong Kong officials said Tuesday nine tourists apparently came down with the deadly disease after another passenger infected them on a flight to Beijing.

The World Health Organization insisted air travel is safe but said its scientists are investigating each case to make sure the disease is not spread through ventilation.

In recent weeks severe acute respiratory syndrome, or SARS, has spread beyond hospitals, where dozens of health care workers became infected, to schools, with at least four closed for several days, and now to air travelers.

Hong Kong officials said the nine tourists became sick after a mainland Chinese man with SARS infected them on a March 15 Air China flight to Beijing. If SARS can be more easily spread through the air -- rather than by close contact with infected people who cough or sneeze -- it could force travel and other restrictions to contain the disease.

"We would want to be sure that it was people sitting next to that person and not the ventilation system in the airplane which was spreading the disease," said Dr. David Heymann, head of communicable diseases at WHO. "We have no evidence of the latter right now."

For one thing, he said, health investigators have followed thousands of passengers who flew with SARS-infected travelers and did not become sick.

However, he said that if they find there are cases that did not involve close contact with someone sick or at high risk, "we will then be very concerned that this might have become airborne."

The airplane cases seem similar to how the disease got its start here -- from one hotel guest who spread it to six strangers staying on the same floor. One expert theorized it might have spread through the air-conditioning system.

From the Hong Kong hotel, the exposed tourists took the disease to Singapore, Vietnam and Canada.

The disease has spread most rapidly through Asian hospitals, some of which lacked the surgical masks and goggles needed to prevent catching the disease from patients. WHO has been distributing such equipment.

The U.S. State Department has warned citizens not to travel to Vietnam because it lacks medical facilities to deal with the disease. In Hong Kong, SARS has spread to 10 hospitals, and the Hong Kong health secretary is hospitalized with SARS-like symptoms.

Hong Kong reported 26 new cases Tuesday, bringing its total to 286 -- more than half the worldwide total of 487. Ten of the world's 17 SARS deaths since Feb. 1 have been in Hong Kong.

In the United States, 39 people have the disease, and the U.S. Centers for Disease Control and Prevention said 32 of those had traveled to Asia. The others were health-care workers or family members of infected patients.

In Singapore, that government has ordered 740 people who may have been exposed to the illness to stay home for 10 days or risk stiff fines.

Meanwhile, a WHO team is in mainland China trying to figure out if the atypical pneumonia that sickened more than 300 and killed five in Guangdong province is the same disease.

Officials with WHO and the CDC said Monday that SARS may be caused by a new form of the coronavirus, one of a few viruses that can cause the common cold.

The coronavirus had been found in SARS patient specimens by scientists at Hong Kong University and by the CDC. But more research confirming that is being pursued.

There is no government-approved treatment for the common cold or SARS, but CDC head Dr. Julie Gerberding said the Defense Department is testing the virus against all known antiviral drugs. There has been progress with antivirals against other respiratory viruses and some of those drugs have been effective in studies against some coronaviruses, she said.

However, WHO virologist Dr. Klaus Stohr, who is working with the agency's network of 11 global labs, said researchers in some labs continue to find signs of another germ family, the paramyxovirus.

"We are a bit puzzled because we are not only dealing apparently with one pathogen but with two. The reason why we believe that both pathogens should be given equal attention is that there is consistent finding of both pathogens in individual patients or of either of the pathogens in other patients," he said.

"What we are seeing actually are three hypotheses."

SARS might be caused by one of those two viruses or "these two pathogens have to come together to cause this very severe outbreak."

The latter theory is that the coronavirus -- which Stohr said lives in immune cells that fight off disease -- destroys or weakens the immunity in the patient so the second virus "has practically an open door to go in and to sicken the patient beyond what this virus would be able to do normally.

"But more research is being done to verify that."