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Sci Tech
Unprecedented teamwork to tame a new killer virus
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The virus causing SARS belongs to the coronavirus family that usually causes common cold. Coronaviruses with a high recombination frequency have the ability to produce new viruses. Scientists in a new teamwork are fighting a common enemy.
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Transmission mainly through air has made protection difficult.
HONEY I have shrunk the world. Joining the ranks of telecommunication and air travel is a new entity — Severe Acute Respiratory Syndrome (SARS), a killer virus disease which has extended its tentacles to more than 30 countries in a couple of months' time. At last count more than 144 people have been killed and at least 3, 300 infected by the killer virus. The numbers are rising by the day.
First surfacing in the Guangdong province of China in November last year, it has since then spread to neighbouring Asian countries and to lands thousands of kilometres away. What is unique about this virus is not just the speed of its spread or its ability to become an endemic disease wherever it has spread, but the suddenness of its origin. The novel SARS virus belongs to the coronavirus family which usually causes the common cold besides diarrhoea and other intestinal illnesses. The coronavirus has earned the dubious distinction of annoying humans with its tenacity, but stayed within limits — has never killed the infected. SARS is the first coronavirus to kill humans.
In the first place what suddenly gave birth to a new virus endowed with the capability to fell its victims? Coronaviruses have a natural propensity for recombination by absorbing bits of foreign genetic material. Infection of a single host with two different coronaviruses can easily lead to recombination and the emergence of new forms. The high frequency recombination property of coronavirus gives it the natural ability to produce new viruses out of the blue. This could have been the most likely origin of SARS. But nobody is quite sure. Only a detailed genome study of SARS would provide these answers.
Scientists at the Genome Sciences Centre, Vancouver, Canada, have succeeded in breaking the genetic code of the virus. This is the first sure step towards developing a test for diagnosing SARS victims. The Genome Sciences Centre had posted the sequence on the Internet (www.bcgsc.bc.ca) immediately after it was broken and later released to the public.
The genetic code is the raw material needed by scientists trying to develop a diagnostic test. One could use these portions of the viral genome to test patients for infection by the virus. For the moment developing a foolproof diagnostic tool is facing some obstacles.
Scientists are facing a setback in finding an animal model to determine the pathogenesis of the virus. Rats that form the first line of animal model have failed the scientists — they are not susceptible to SARS. This leaves with an option of going in for larger animals like monkeys. But experimenting on monkeys is expensive and time consuming. How the scientific community will overcome this obstacle remains to be seen.
In the meanwhile scientists working around the world have confirmed the novel nature of the virus. The presence of antibody in serum specimens in only those infected with the virus, according to a paper published in The New England Journal of Medicine is a testimony of SARS' novel nature. Thomas G. Ksizek and his team in the paper have postulated that the virus could have originated in animals and mutated or recombined to give it the power to infect and be transmitted from one person to another before striking a deadly blow.
It is unlikely that SARS is an outcome of some scientists trying to produce bio-weapons. The low mortality rate of 3-4 per cent compared to more than 80 per cent in the case of anthrax is not what scientists would be looking for in a virus to be used as a bio-weapon.
United we stand...
SARS would be long remembered for not only its speed of spread to far-flung countries, but also the real test of the scientific community around the world to come together and work as a team to understand the characteristics of the virus, etiology and pathogenesis of the disease. "Thirteen laboratories are working across the globe in an unprecedented joint effort to identify the major cause and develop a diagnostic method within a month," noted Hitoshi Oshitani, WHO's regional adviser on communicable disease surveillance and response, Manila.
The Internet has yet again demonstrated its powers. It had helped the scientific community to stay in touch and inform the doctors and care providers about the disease and the precautions to be taken to contain the disease. The New England Journal of Medicine and New Scientist made its scientific papers feely available online. This is probably an opportune time for the publishing houses to see the merits of providing online access to its journals for free.
The medical fraternity, true to its reputation, did not shy away from responsibility despite being at a very high risk of contacting the disease. Many doctors and nurses who fell prey to the virus despite knowing the risks involved is a testimony to their dedication. Authors of a paper published in The New England Journal of Medicine had faithfully dedicated their work to the `nurses and doctors for their selfless and heroic devotion to duty'.
Talking about devotion and dedication, a special mention has to be made about Carolo Urbani, Director of infectious diseases for the Western Pacific Region of the World Health Organization. He was the first person to warn the world about the virulent SARS virus after seeing many nurses in a hospital in Hanoi, Vietnam, where he was working, die. If not for his timely warning more people would have fallen prey to the virus. Ironically, he fell a victim himself to the virus. Even in death he exhibited his noble character by donating his lung tissue for further scientific investigation.
Refusing to heed to his wife's request not to expose himself to the virus at the hospital, he had shot back saying, ``If I can't work in such situations, what am I here for? Answering e-mails, going to cocktail parties and pushing papers?'' That in a nutshell portrays the character of Dr. Urbani. Little wonder that the scientific community was unanimous in their decision to pay a befitting tribute to such a soul by naming the virus after him. A paper in The New England Journal of Medicine has proposed calling it as Urbani SARS-associated coronavirus.
We can anticipate more such new viruses and outbreaks in the future. It's time to learn some lessons from this experience and prepare ourselves for the future.
R. Prasad
in Chennai
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