April 8, 2003	Tuesday	Safar 5, 1424

LOS ANGELES: In New Zealand, Maori tribesmen have been warned against performing their customary nose-rubbing greeting on tourists. In Thailand, visitors from affected countries are given mandatory medical check-ups at airports and seaports, and are required to wear face masks throughout their stay.

Masks — many of them boldly and stylishly decorated — are now sported everywhere on the streets of Hong Kong.

Severe Acute Respiratory Syndrome, known as SARS, has infected more than 2,416 people and killed at least 89, with five new deaths added on Saturday. It has caused school closures, travel restrictions, the withdrawal of diplomats, the quarantine of thousands and the abrupt cancellation of hockey games, scientific meetings and rock concerts.

The outbreak has sent out ominous tendrils from the Guangdong region of southern China where it is believed to have originated, to other parts of the world, including Canada and the United States. In the United States, 115 cases have so far been tallied in 29 different states.

What are we facing in the weeks and months to come? Infectious disease specialists say they cannot yet tell us.

They say that the eventual ranking of SARS in the laundry list of plagues and scourges that pick off countless human beings every year depends on many unknowns. A poorly-understood confluence of biology, ecology and human activity dictates whether a tiny, invisible microbe spreads through the world wreaking havoc or shows some muscle and then falters, fades, or ends up marginalized in slim pockets of the world.

“I don’t think we really know where we’re going yet on this one; we’re in the third or forth line of a three-act play,” said Dr Michael Osterholm, director of the Center for Infectious Disease Research and Policy at the University of Minnesota’s School of Public Health. “It really is a function, now, of letting the virus show its hand.”

Osterholm and others praise the efforts of the World Health Organization, Centers for Disease Control and Prevention and other public health bodies as efficient and appropriate. Cases have been quickly tracked and exposed individuals quarantined. Health care workers wear high-filtration masks when caring for patients and the patients are treated in reverse-pressure hospital rooms that allow air to flow in but not out.

The likely viral culprit has already been isolated and is under analysis. A definitive, diagnostic test for that virus should be available within weeks, and the quest for a vaccine is under way.

Experts also point out by way of context that a scourge we take for granted is far more lethal than SARS has proven so far. Each year, the influenza virus infects 10 to 20 per cent of Americans, hospitalizing 114,000 and killing 36,000. Worldwide, influenza kills 250,000-500,000 people annually.

“Obviously, SARS is of concern, but the number of deaths so far is still dwarfed by the number of people who die each week from influenza-related complications,” said Dr David Pegues, director of infectious diseases control at the University of California, Los Angeles Medical Center.

By far the top candidate for the cause of SARS is a previously-unknown virus that belongs to the coronavirus family. Coronaviruses have never before been shown to cause dangerous disease in human beings. Discovered in the 1960s, they were named corona. They cause about 20 to 30 per cent of the cases of common cold.

Because the viruses have not been considered dangerous human pests, they haven’t been a hotbed of research or medical concern, said coronavirus expert Dr Michael Lai, professor of molecular microbiology and immunology at the University of Southern California’s Keck School of Medicine.

In contrast, specialists have been hugely worried about the emergence of a deadly, new strain of influenza, like the one that killed 20 to 50 million people worldwide in 1918.

The flu virus is such a threat because it is very prone to accumulating genetic changes. It readily treats chunks of its genome like noxious trading cards, swapping them with chunks from related viruses in pigs and birds — sometimes coming up with lethal, new variants.

The prospect of a deadly, new flu still looms large. However, the emergence of a virulent new coronavirus shouldn’t be a big surprise, said Dr Donald Burke, professor of international health and epidemiology at Johns Hopkins University Bloomberg School of Public Health.

There are many coronaviruses that cause lethal respiratory sicknesses and diarrhea in animals such as pigs, birds, cats and cows. Coronaviruses are also quite adept at trading genetic material should they come into contact with these related viruses.

Determining the sequence of the SARS virus will provide valuable clues as to its origins and offer clues as to how to fight it.

A virus’s ability to get from victim to victim is key to the impact it makes. The Ebola virus, fodder for terrifying books and feature films, mercilessly kills at least half of the people it infects — more than 80 per cent, in some recorded outbreaks. But it remains marginalized in parts of continental Africa because the disease acts swiftly and infection requires direct exposure to contaminated blood or other secretions.

To scientists who monitor infectious diseases, the emergence of SARS serves as a reminder that viruses remain mysterious and unpredictable foes. Today, as people fly across the globe dragging all manner of exotic, invisible germs in their wake, these creatures are showing their cards as never before.”—Dawn/LAT-WP News Service (c) The Washington Post.