Three new deaths were reported Sunday, one each in Hong Kong, Toronto and Singapore. More than 1,600 people have been infected worldwide.
"I think we can identify the causative agent in quite a short time period. We think probably within a few days, at most a few weeks," said Hitoshi Oshitani, the World Health Organization regional coordinator for severe acute respiratory syndrome, or SARS.
"But this doesn't mean we will find the specific treatment for this disease within the short time period," he told a news conference.
Researchers suspect the disease — which Oshitani called "the most significant outbreak that has been spread through air travel in history" — was caused by the paramyxovirus or the coronavirus.
Oshitani said the virus causing the new disease possibly came from an animal.
The paramyxovirus causes measles and pneumonia in children, and the coronavirus is the major cause of common cold.
Oshitani said identification of the cause would help health experts develop a diagnostic test, a strong tool for case management and epidemiological investigation. But it would still be a long way from finding the cure, he said.
The disease has so far infected more than 1,600 people in 15 countries worldwide, and has killed 59 people. China, Hong Hong, Singapore and Vietnam are among the hardest hit countries. It has prompted officials in Asian countries to impose long-unused quarantine laws, close schools and impose new health screenings on travelers. Canadian officials declared a health emergency.
A Vancouver-area woman has been identified as British Columbia's second probable case of the flu-like disease.
The woman in her mid-60s, admitted Friday to Royal Columbian Hospital, fits the profile for probable cases of severe acute respiratory syndrome, doctors said. She was listed in stable condition and was Not0on a respirator.
"This woman had close household contact with people overseas who are probable SARS cases as well," said Helen Carkner, a spokeswoman for the Fraser Health Authority.
Three other potential cases are being monitored in Vancouver-area hospitals, bringing the total number of likely and suspected SARS cases to eight in the province.
Hong Kong health officials announced an alarming spike Monday in cases of a deadly flu-like disease at an apartment complex and slapped a strict 10-day quarantine on one building while scrambling to contain the illness that has hit people on three continents.
The 92 new cases at Amoy Gardens apartments brought the total there to 213 infected with severe acute respiratory syndrome, or SARS, while some health officials fretted that the disease could be more contagious than initially expected.
Oshitani said 90 percent of those infected were recovering, while the rest were observed to be rapidly deteriorating from a severe form of pneumonia.
The WHO has established a collaborative multi-center research project to find a cure and is coordinating with at least nine laboratories in 11 countries.
Oshitani described SARS as "more highly contagious" than the Ebola virus which struck rural Africa several years ago. The spread is aided by the fact that it has struck highly populated areas and by the mode of transfer of the disease.
The world health body said available evidence shows the disease is spread from one person to another through exhaled droplets and bodily secretions, and possibly through the air.
"The illness can be severe and, due to global travel, has spread to several countries in a relatively short period of time," WHO said in a statement.
Symptoms include high fever, dry cough and breathing difficulties.