Possible Clue to Cause of Mystery Illness Identified

Microbiology professor John Tam, one of the scientists who made the discovery, said, ”From the shape of the virus, it belongs to the paramyxoviridae family.”

Paramyxoviruses are a large group that includes the viruses that cause measles and mumps. They are also a cause of what health experts call emerging infections — diseases not seen before.

Dr. Julie Gerberding, head of the U.S. Centers for Disease Control and Prevention, cautioned that the suspected paramyxovirus had been found in the noses of the victims and not in their blood or tissues, so it was still not certain the virus was behind the illness.

She said it is also possible that those who are ill have another viral or bacterial infection that may be causing or contributing to the disease, which researchers have termed “severe acute respiratory syndrome,” or SARS.

“Seeing something in a nasal swab is not the same thing as identifying or confirming that it is a causal relationship. So a great deal of work needs to be done,” Gerberding said.

Nevertheless, the finding is the first potential clue to emerge in the three weeks since the illness came to the attention of health experts.

The World Health Organization said in a statement released Wednesday that the discovery “will help physicians move from the current ‘hit-or-miss’ approach to treatment to a more precise selection of drugs with a greater prospect of cure.”

But researchers warned that there was still some distance to go.

“It is similar to seeing the shadow of someone you think you know but the face and the details will only become clear with further testing,” Dr. David Heymann, the WHO’s communicable diseases chief, told Reuters.

Experts at the WHO said that SARS has spread to Europe, North America and Australia by air travel but seems not to be spreading within those regions. The WHO issued its first global health alert in a decade on Saturday.

“That shows the alert is working,” said Guenael Rodier, WHO director of disease surveillance and response.

The WHO reported Wednesday that 264 cases of SARS appear to have emerged since Feb. 1 and that nine people have died from the disease. Most cases have been concentrated in Hong Kong, which has more than 120 people suffering from the disease; Singapore, which is reporting 23 cases; and Vietnam, where nearly 60 are affected. Confirmed or possible cases have also been reported in Germany, Britain, Romania, Australia, Brunei, Spain and the United States.

The illness may have originated in China’s southern Guangdong province where 305 people became ill and five died.

On Wednesday the CDC reported that 11 people in the U.S. may have the disease. But Gerberding said it was difficult to tell who had the syndrome and who had run-of-the-mill pneumonia.

“The symptoms of concern are fever, cough, difficulty breathing or chest discomfort and in flu season these are very common symptoms,” Dr. Gerberding told reporters.

“The 11 (U.S.) people that we are talking about today have a travel history, fever and respiratory symptoms that make them fall into a case definition for a suspect case,” she added.

Dr. Gerberding said the CDC was erring on the side of caution by broadly defining suspect cases as those who had pneumonia and had recently traveled to Southeast Asia.

Investigators said Wednesday that seven of those infected, including one who died, had all stayed on or visited the same floor of a Hong Kong hotel before the outbreak prompted a global alert. This discovery may be significant, because until now officials have said close personal contact is necessary to catch the illness.

Dr. Margaret Chan, director of the Hong Kong Health Department, did not say whether there was any other connection among the guests who got sick other than that they all stayed on the ninth floor of the hotel between Feb. 12 and March 2. Dr. Gerberding told reporters Wednesday that two of those who became infected were in close contact with one another, but that the other relationships had not been determined.