March 31, 2003, 4:27PM Reuters News Service

A family leaves the Amoy Gardens apartment complex today in Hong Kong. The complex was badly hit by a mystery illness that is spreading across Asia.

HONG KONG - More than 100 people in one Hong Kong apartment block were suspected to have been infected by a deadly pneumonia virus, officials said today, triggering fears that the killer disease was being spread through air or water.

At least two more people died from the Severe Acute Respiratoy Syndrome, known as SARS, in Hong Kong during the day, taking the death toll in the city to 15 and to 61 worldwide.

A total of 213 people living in the Amoy Gardens housing estate were confirmed or suspected to be infected with SARS, of whom 107 are from Block E of the complex, Health Secretary Yeoh Eng-kiong told a news conference.

Authorities have quarantined more than 200 other residents in Block E in an effort to contain the virus, which has infected almost 1,700 people across the world, mostly in Asia.

Dozens of health workers in full surgical gear stood guard at the entrance of the apartment block to stop any residents from leaving as policemen in masks cordoned off the area.

But residents said many families had already fled.

The number of those infected in Amoy Gardens, in the heart of the teeming Kowloon district, is almost one-third of the total number in Hong Kong, a city of seven million people.

Two elderly men died of the disease today, bringing the death toll in the city to 15.

Amoy Gardens is in a maze of crowded housing estates and smoke-spewing industrial buildings in one of the most densely-populated areas in the world.

Proliferation of the virus in such an environment is certain to create havoc and put immense pressure on public hospitals, which are already stretched and barely able to cope.

"We are now examining all possible angles, to see if it is airborne or in the (building's) water mains," a government spokeswoman said of the virus.

Health Minister Yeoh said: "We are now detecting the virus in the faecal material (from Amoy Gardens patients). So that would be one possible potential cause of spread to large populations under unusual circumstances."

"There was a suggestion that the sewage system was leaking...we are investigating."

Experts have previously said the virus was carried by droplets from sneezing or coughing, but the high number of cases at Amoy Gardens has raised fears the virus could be water or airborne.

"Up till today, it is spread through droplets. But no one can rule out that it could be airborne, because viruses change all the time," Yeoh said.

Fearful of the disease, some companies have ordered staff to work from homes while others have begun to organise backup, skeletal teams in case their workers get infected.

Hong Kong and Singapore have closed schools in a bid to contain the disease and quarantined those exposed. Besides these two cities, deaths have also been reported from Vietnam, Canada and from China, where the disease originated in November.

A doctor from the World Health Organization, who was infected in Vietnam after he had identified the virus, died in a Bangkok hospital at the weekend.

The disease has triggered tighter screenings at many airports and a growing number of countries have advised citizens against unnecessary travel to the worst-affected areas.

In Singapore, nurses have been deployed at the airport to check incoming passengers.

Apart from scaring away tourists, the epidemic has disrupted business in Hong Kong. A growing list of shops, banks and offices have shut after employees were found infected.

Some expatriates have departed quietly, taking their families with them on home leave.

The U.S. Centers for Disease Control and Prevention warned on Saturday that the virus may wreak more havoc.

"The potential for infecting larger numbers of people is great," said its director Julie Gerberding. "We may be in the early stages of what could be a larger problem."

Cases have also surfaced in the United States, Germany, Britain, France, Japan, Ireland, Italy and Taiwan.

Almost 1,700 people have been infected worldwide, but some have since recovered. About four percent of the people who catch it die from the disease.