CAMBODIA has so far been spared an outbreak of the deadly SARS virus sweeping the

globe. But with travelers arriving daily from other countries, health officials have

warned that SARS, or Severe Acute Respiratory Syndrome, remains a threat.

Tourists wearing protective masks fill out departure cards at Phnom Penh International Airport on April 3.

The disease continues to defy efforts by health officials to contain it, despite

declining infection rates in some countries. The World Health Organisation (WHO)

said it was determined to ensure the disease made no inroads here.

"To be frank, there isn't a single country in the world where [the public health

infrastructure] is adequate, because we don't know how the virus is spread,"

said WHO representative Dr Michel Jancloes. "But we're now making some significant

gains. In Cambodia, we improve our capacity each day."

Health professionals said prevention was the first line of defense. Sok Touch, head

of the communicable disease control department at the Ministry of Health (MoH), said

officials at the country's international airports and immigration checkpoints on

the border with Vietnam and Thailand had been instructed to screen and quarantine

potential SARS carriers.

The MoH announced on April 8 that it would request airlines to provide proof their

passengers had been screened for the disease before leaving affected areas such as

Taiwan, China's Guangdong and Shanxi provinces, Hong Kong and Vietnam's capital Hanoi.

Passengers must also fill out health declarations detailing any symptoms and their

travel route.

Any passenger suspected of carrying the virus will be sent immediately in specially

designated ambulances to one of two referral hospitals: Calmette Hospital in Phnom

Penh or Siem Reap Referral Hospital.

The ministry said to date at least nine suspected cases had been referred to Calmette

Hospital, but tests showed none had the disease. The most recent case, a British

woman who was holidaying here, was released from quarantine on April 8.

The MoH said the isolation unit at Calmette could hold about a dozen suspected SARS

patients.

"They have the facilities and people to deal with respiratory emergencies,"

said Dr Jancloes. "The same types of facilities are now being developed in Siem

Reap."

Since medical evacuation of SARS patients is not allowed in any country, said WHO,

efforts were being made to prepare Cambodia in the event of a small outbreak.

Health officials said that if the infection arrived here, the lack of modern infrastructure

might prove a saving grace. That is because SARS seems to be spread in one of two

ways: direct contact, and through the labyrinthine ventilation and plumbing pipes

that link modern buildings.

"So far the big spread has been in countries with quite sophisticated building

and hospital facilities," said Severin von Xylander, a WHO official working

here. "It might actually be an advantage for Cambodia to have a low level of

infrastructure without centralized air-conditioning and ventilation."

At Hong Kong's sprawling Amoy Gardens apartment complex, more than 200 people contracted

SARS. Many of the cases appear to have spread vertically from one apartment to another

in the 33-story building.

The Associated Press reported WHO's infectious diseases chief, Dr David Heyman, as

saying that there appeared to be "some environmental factor, such as water or

sewage, which is taking this disease from one human to another". A health official

in Hong Kong voiced his theory that cockroaches had carried the disease between apartments.

As one of the most frightening viral outbreaks in decades, the disease has severely

dampened international tourism and sown mistrust between Asian nations. The Ministry

of Tourism said tourist arrivals here have dropped to almost half the level of this

time last year.

Rattled by the potential for disaster, the country's neighbors have enacted strict

measures to guard against the virus. In Thailand, which has recorded seven SARS cases

and two deaths, all Thai citizens returning from infected areas must stay at home

in quarantine for 14 days. Some hotels in Hong Kong are turning away guests from

mainland China.

Despite the hysteria, health officials are urging calm. The lethality of the virus,

while significant at 4 percent, does not compare with other highly contagious viruses

such as Ebola, which can kill 90 percent of its victims. And given modern facilities,

doctors are usually able to treat successfully the symptoms of the disease.

Five countries have reported cases of local transmission of the virus: China, Singapore,

Vietnam, Canada and Taiwan. Subsequent outbreaks have been traced to single contagious

patients, known as super-spreaders, who infect health workers and those with whom

they come into close contact. But once the patient is quarantined, the number of

new infections often drops.

But even with remarkable medical progress, there is little prospect of a SARS-free

world.

"You have to realize this isn't going to go away anytime soon," said Beth

Leaneagh, nursing supervisor at Phnom Penh's International SOS Clinic. "It's

something we have to learn to live with. It's important not to panic."

The SOS Clinic, which has fielded a flood of inquiries and consultations about the

virus, is yet to diagnose anyone with SARS. A flyer posted outside the entrance details

symptoms of the infection and asks people to remain outside the building during their

SARS consultation.

"We are just being prepared," she said.

What is it?

SARS, Severe Acute Respiratory Syndrome, is a viral infection believed

to be caused by the coronavirus, a viral family named for the protein ëhaloí around

the infectious particle. This virus is responsible for illnesses such as the common

cold and can infect both animals and humans. It can survive in dry air for up to

three hours, though not under direct sunlight.

Where did it come from?

The outbreak is suspected to have originated in Chinaís Guangdong province

in November last year. As of April 9 it has infected 2,671 people in 17 countries.

Symptoms

High fever (almost all patients); cough, nasal congestion, sneezing; chills

and headache; severe muscle and joint pain; difficulty in breathing ó similar to

asthma; continuous localized pain in the chest, which increases when taking a breath.

Symptoms appear between two and 16 days after exposure to the virus, which is not

thought to be contagious until these symptoms appear. Although a reliable laboratory

test is being developed, most diagnoses are based on identifying the symptoms.

What does it do?

SARS causes ëatypical pneumoniaí. In most respiratory infections, the

lungs fill with fluids which block oxygen exchange. With SARS, the small air sacs

in the lungs responsible for oxygenating the blood actually collapse.

How is it transmitted?

Not clear, but SARS has been shown to be transmitted through airborne

droplets due to coughing or sneezing and personal contact. Other pathways are being

investigated.

Sources: WHO, New England Journal of Medicine