On February 26 this year, a 48-year-old American businessman boarded a routine flight from the Guangdong province of China to Hanoi in Vietnam. It was not a comfortable flight-his head ached, his body ached. By the time he reached Hanoi, he could no longer ignore the raging fever and relentless dry cough that racked his body. He was admitted to the hospital, where he died.

AIR OF UNEASINESS: People in Hong Kong wear surgical masks to protect themselves from the possible spread of SARS infection

Nobody knew why. But they soon realised that his killer was at large and had attacked all those who had been close to him during his illness. Suspicious of the number of medical staff who soon reported similar pneumonia-like symptoms, Carlo Urbani, a 46-year-old Italian doctor working for the World Health Organisation (WHO), duly reported to it that something serious was amiss. And so began a real-life saga whose script could give the best Hollywood screenwriters a run for their money.

By March 15, when five people were dead and over 150 affected worldwide, WHO issued a rare global emergency alert. India was unaffected, but took note. Union Health Minister Sushma Swaraj, who was in Hyderabad when the first reports arrived, immediately called S.P. Aggarwal, director-general of health services, and Health Secretary S.K. Naik. A high-level official meeting was convened to discuss the best course of action for India.

The mysterious new killer disease, for want of a better name, was called "Severe Acute Respiratory Syndrome" (SARS) by WHO. Its tentacles quickly spread across the globe. The initial victims were from neighbouring areas-Hong Kong, China, Singapore and Vietnam. Soon, thanks to air travel, reports of SARS began to read like a geography lesson. One of the first victims was reported in Toronto, Canada-a passenger who had flown in from Hong Kong. The scare spread. One by one, nations from all corners of the globe-Romania to Australia-began reporting cases of SARS.

Each day, the toll of victims rose as steadily as those in Iraq. There was no doubt about who was winning in this war. By April 2, WHO reported over 2,200 cases of SARS and 78 deaths in 13 countries. Among the victims was Urbani, the doctor who first brought SARS to the world's attention in Hanoi. WHO took the drastic step of effectively quarantining the worst-hit areas-Hong Kong and Guangdong. The killer was on the rampage and its identity still a mystery.

Meanwhile, the race is on in the scientific community to identify the cause of what could be the biggest health epidemic of the 21st century. Fairly early on, scientists were convinced that the agent was a virus. The symptoms associated with SARS resemble atypical pneumonia, usually associated with viruses such as the influenza virus, ADENO virus and other viruses.

EXTRA CAUTIOUS: Airlines staff worldwide are viewing the SARS scare seriously

Meanwhile, reports from Germany and Hong Kong suggested that the agent was a new member of a family of viruses that also cause measles and mumps, called paramyxovirus. But scientists at the US-based Center for Disease Control, the key agency for any communicable disease, reported that they had detected a previously unrecognised strain of "coronavirus"-a family of viruses also responsible for the common cold. Under electron microscopy, the virus showed the characteristic "crown like" appearance that gives the coronavirus its name.

The conflicting reports have only added to the uncertainty, raising several theories. The first is that the actual killer is a coronavirus and the paramyxovirus a harmless one that's just there. The second is the reverse-the paramyxovirus is the "bad one" and the coronavirus, the innocent bystander. The third hypothesis talks of a viral teamwork-coronaviruses are known to live in the body's immune cells and weaken a patient's immunity. The paramyxovirus than walks in and goes on the rampage, unchallenged. There is also the possibility that these viruses are not the culprits and the actual killer remains undetected.

How did the virus originate? It is reported that Guangdong in China was the epicentre of the disease. Cases of typical pneumonia had been reported there as early as November 2002, and this has been linked to the current SARS outbreak. Many questions remain unanswered. Scientists in Hong Kong and of WHO suspect that the virus most likely originated in animals there, mutated and crossed species.

Once inside human beings, it is "a war of attrition between the human immune system and the virus", says J.C. Suri, head of respiratory diseases at Delhi's Safdarjung Hospital. In those with a weaker immune system or higher exposure to the virus, the virus wins. It then finds its way to the lungs where it attacks and kills the tissues, causing respiratory problems. The symptoms appear within two to 10 days. The virus spreads through close contact with an infected person and is also airborne through aerosol droplets, such as a cough. The symptoms are dangerously common making it difficult to distinguish from flu. The good news is, it's less infectious than the influenza virus. Only 5 per cent of its victims die. While there is no specific treatment-doctors treat the symptoms instead of keeping them under control-a cocktail of the anti-viral drug ribavirin and steroids has been used in Hong Kong apparently to good effect.

CHECKED IN: Passengers are being screened for signs of SARS at all airports

The biggest victim has been the region's travel and tourism industry. Countries like Hong Kong and Singapore rely heavily on tourism for their economy. Says Subhash Goyal, chairman, STIC Group: "Tourism to India has not been affected. But outbound traffic to Hong Kong and Singapore has decreased by 40 per cent, and to China by 50 per cent." Following the new WHO advisory, travel to Hong Kong is expected to decline sharply. There were some predictions in the industry that due to the Gulf War, trouble-free south-east Asia would be the world's tourist hot spot. SARS, however, has put paid to that. In a recently concluded meeting at Kathmandu, Nepal, the World Tourism Organisation (WTO) agreed that the fear of the virus would stop people from travelling and significantly affect tourist flow across south and south-east Asia in the peak season.

Airline companies, however, are more cautious in their analysis. On being asked how badly SARS could affect outbound travel from India, Cathay Pacific Country Manager Tom Owen says, "India has seen a recent softening in passenger demand. However, it is difficult to attribute the drop in demand to any single source as the situation is further complicated by other external factors, including the war in the Middle East."

Cathay Pacific, like many other airlines, has alerted staff posted at check-in counters at Hong Kong and other countries to be extra vigilant about passengers who appear ill. Cabin crews have also been given guidelines on dealing with passengers suspected of having SARS.

Many countries have started taking precautions. Thailand has gone to the length of invoking an emergency regulation to give health officials the authority to quarantine suspected SARS-infected passengers for up to two weeks.

INDIA'S INITIATIVES

All incoming passengers are being monitored by immigration officials at international airports and ports. Indian embassies have been told to warn those applying for visas that they would be denied entry if suspected of SARS.

Disembarking passengers have to fill up prescribed forms designed by the Health Ministry on SARS which will help trace suspected victims.

All hospitals in the country have been placed on alert to prepare for the unexpected.

The National Institute of Communicable Diseases has been designated the nodal agency for monitoring all possible cases.

The Government will import diagnostic kits from Germany, via WHO, for detection of SARS.

In India, the Health Ministry has posted medical officers on duty on 24-hour alert at all international airports. Immigration authorities initially had instructions to closely observe passengers on flights from SARS-affected areas for any symptoms. This has now been extended to all flights. Whether that will really stop SARS from entering the country is questionable.

Ask Monisha Dulharamani, 38. Flying in from Singapore last week with a cold, she braced herself to be checked by doctors at Mumbai's international airport or even be held up at the immigration counter. But she walked in easily, without any checks for SARS. "In fact, the airlines were more worried about spraying the aircraft with some vile-smelling medicinal spray to make sure we didn't carry any bacteria with us. There were no doctors, no security and absolutely no fuss," she says.

So far there have been no reported cases of SARS in India. But has adequate precaution been taken for it to remain that way? The Health Ministry thinks so. They have taken several steps. International airports and ports are under observation. Prescribed forms on SARS will be distributed to all disembarking passengers. All hospitals have been alerted. State governments have been asked to take suitable measures. "We are creating awareness of the disease and taking adequate precautions," says Bhawani Thyagarajan, joint secretary in the ministry.

But it is a fine line between being alert and causing panic. Minister Swaraj emphasises the point. "While the medical authorities should be on full alert, we should not cause panic among the general public especially when no SARS cases have been reported in India," she says. The National Institute of Communicable Diseases, Delhi, has been designated as the nodal authority. Suspect cases will have to be reported to state governments, the NICD and Health Ministry. Ministry officials say that diagnostic kits for detecting the virus will be imported from Germany via WHO and will be distributed to NICD and the National Institute of Virology, Pune. In Delhi, the All India Institute of Medical Sciences, Safdarjung Hospital and Ram Manohar Lohia Hospital have been designated the nodal hospitals. "We are well prepared," says R.N. Salhan, medical superintendent at RML.

Doctors and nurses have been made aware through workshops and circulars. While it is impossible to screen all patients with pneumonia-like symptoms, any suspect case will be asked about foreign travel and placed in isolation, he says. For any possible SARS patients with severe breathing difficulties, ventilators are available in all 15 operating theatres and emergency rooms in the hospital. As for protection of doctors and nurses, he says it is routine for them to take precautions like masks when examining potential patients.

But SARS is not just another killer disease. "We are always prepared for the unexpected," says N. Gupta, head, medical division, RML. Alternatively, we could just pray.

-with Nidhi Taparia Rathi