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Last Updated

20 Mar 2003

Source: New York Times, March 20, 2003

W.H.O. Reports Gains Against Respiratory Outbreak


Officials at the World Health Organization expressed increased optimism yesterday that scientists had found a virus that could be the cause of a mysterious respiratory ailment, adding that if the research continued at its surprising speed, a test to detect cases could soon be developed.

Such a test would be a major step in controlling the outbreak, which has killed at least nine people and sickened hundreds more. An accurate test could detect individuals who might be healthy carriers of the virus and those who have mild cases. The test could also help guide doctors to move from the current hit-or-miss treatment approach to more precise selection of drugs that might help patients recover.

But much more work needs to be done to be sure that the suspect virus is the true cause of the ailment that W.H.O. calls SARS, for severe acute respiratory syndrome. The agency has declared the condition a "worldwide health threat."

Yesterday, W.H.O. increased the cumulative number of cases to 264, including all nine deaths since Feb. 1. The previous total, on Tuesday, was 219 cases, including four deaths at that time. In addition, Chinese health officials have said that an outbreak before February sickened 305 people in Guangdong province, leaving five dead.

The cases reported by W.H.O. occurred in Britain, Canada, Germany, Hong Kong, Singapore, Slovenia, Spain, Taiwan, Thailand, the United States and Vietnam. Most cases involve hospital workers or individuals who have had close household contact with someone who is infected, and many are recovering after nursing care but without specific drug treatment.

For several days, Dr. Julie L. Gerberding, the director of the Centers for Disease Control and Prevention in Atlanta, has said her agency was investigating a number of suspect cases. But the 11 cases reported from the United States made this the first time this country has been on W.H.O.'s list of nations where the disease has been identified.

Dr. Gerberding said the number of cases would vary daily as the epidemiological and clinical investigation proceeded. She said her agency was using a broad definition purposely to cast a wide net for cases to avoid missing any true ones.

The definition includes people who have traveled to an area with documented transmission of SARS within 10 days of becoming ill or having had contact with an individual suspected of having SARS.

Signs and symptoms include a fever of 100.4 degrees Fahrenheit and respiratory symptoms including cough, shortness of breath, difficulty breathing or chest X-rays showing pneumonia or acute respiratory distress syndrome.

But using such a broad definition, particularly in a season when respiratory illnesses are common means that the 11 cases may fall by the wayside as the investigation progresses, Dr. Gerberding said.

C.D.C. has received more than 40 calls concerning suspect cases since Monday, she said.

In Hong Kong, the health department said the first group of patients there had stayed in a hotel in Kowloon last month. That group included three visitors from Singapore, two from from Canada, one from mainland China and a seventh from Hong Kong. At least two of the patients visited each other in the hotel. Health officials are trying to reconstruct the interactions of the other five guests.

On Tuesday, scientists from laboratories in Hong Kong and Germany reported having found particles that seem to belong to a large family of viruses, paramyxoviridae, in three patients with suspect SARS cases. The family includes the viruses that cause croup, respiratory disease, measles, mumps, rubella and a number of diseases in animals, including Newcastle disease, which is lethal to chickens; canine distemper virus and rinderpest, which affects cattle and other animals.

In recent years, scientists have added the Hendra virus, which infects horses, and the Nipah virus, which infects pigs, to the list of paramyxoviridae that can infect humans.

The key to detecting the viral particles in the three SARS patients appears to have been the use of electron microscopes, a powerful instrument not used in many virology laboratories.

Dr. Larissa Kolesnikova, a Russian microbiologist who is working at the Institute for Virology in Marburg, Germany, said yesterday that she had used specimens from a Singapore doctor who attended a medical meeting in New York City last week and his mother-in-law. They were taken off a plane on a scheduled stop in Frankfurt on their return flight home.

Dr. Kolesnikova said she had peered into an electron microscope at the doctor's specimens for three hours on Saturday, then came back and identified the particles on Sunday morning. Meanwhile, scientists at the Chinese University in Hong Kong were identifying similar particles, also using an electron microscope. "With the confirmation from Hong Kong, we are more confident" that the virus might be the cause of the outbreak, said Dr. Hans-Dietrech Klenk, the director of the Marburg institute.

However, Dr. Klenk and W.H.O. officials emphasized that much more work was needed to be sure the virus was the true cause of the outbreak.

A team headed by Dr. John Tam, a microbiologist in Hong Kong, used the electron microscope findings to determine the nucleic acid sequence of the virus's molecular structure, said Dr. Klaus Sthl , a virologist and epidemiologist who is leading the health organization's scientific team investigating the illness.

The Chinese scientist also used a technique known as PCR, for polymerase chain reaction, to get strong hints that the suspect virus had infected three patients in Hong Kong.

Dr. Tam has agreed to share the information on a secure Web site so that other laboratories in the W.H.O. network can try to confirm and advance the findings in cell cultures and animals in the laboratory.

If a paramyxoviridae virus is confirmed as the cause of SARS, the World Health Agency would consider recommending the antiviral ribavirin as a treatment, said Dr. David L. Heymann, a W.H.O. official.

Given the problems infectious diseases often cause in the military, American officials said the Department of Defense was keeping an eye on the movement of this disease.

"You can be sure that the D.O.D. is well up to date on the status of this outbreak and investigation, and they are doing what is necessary to protect the troops," Dr. Gerberding said.