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Identity of mystery pneumonia bug sharpens

Questions raised over readiness for lethal SARS epidemic.
20 March 2003


Laboratories have been comparing the pathogen to known types of paramyxovirus.

As laboratories worldwide home in on the virus responsible for the mysterious global outbreak of pneumonia, critics say that researchers could have been better prepared to anticipate the epidemic.

So far, 264 people worldwide are known to have been infected and 9 have been killed by Severe Acute Respiratory Syndrome (SARS). This flu-like condition is characterized by high fever and breathing problems. Fears began escalating after the World Health Organization put out an exceptional alert last week.

Laboratories in Hong Kong, Germany and Singapore have now found signs that the culprit may be a new type of paramyxovirus - one of a family of viruses that cause respiratory illnesses, measles and mumps. They examined the genetic sequence of the virus and looked at its shape through an electron microscope; both matched those of known paramyxoviruses.

Immunologists stress that it is too early to conclude that a paramyxovirus definitely causes the lung illness - the virus could be a coincidental infection. To be sure, the collaborating labs must find tell-tale viral DNA in all patients and show that their blood contains specific antibodies against the virus.

If the labs' suspicions are correct, there are few drugs and no vaccine to fight this pathogen, warns Christopher Broder, who studies paramyxoviruses at the Uniformed Services University in Bethesda, Maryland. One drug, ribavirin, could be tried; this is used to treat the paramyxovirus that causes respiratory syncitial virus infection in children.

Heads up

New strains of paramyxovirus have killed humans twice before, after jumping from animals. In 1994, two stable workers died in Australia having contracted a horse strain called the Hendra virus. And in 1998, 105 Malaysian pig farmers died from the related Nipah virus. In both cases, the animals were first infected by fruit bats.

Events such as these have prompted some experts to ask why the latest outbreak wasn't better anticipated. "If we had our act together we could have seen it coming," says Donald Burke, who studies the spread of infectious diseases at John's Hopkins University in Baltimore.

If we had our act together we could have seen it coming
Donald Burke
John's Hopkins University

Burke argues that there has been time enough to develop more rapid diagnostic tests to identify new strains of paramyxovirus, and to assess potential strains brewing in animals. "No one is doing anything approaching a systematic survey of paramyxovirus in other species," he laments.

These concerns are echoed in a US Institute of Medicine report co-incidentally issued this week. Its authors - of whom Burke is one - warn that the world remains poorly prepared to deal with emerging pathogens. They call for more investment to boost surveillance and response to potentially threatening bacteria and viruses.

Other experts are more sanguine. Infectious-disease researcher Stephen Morse, of Columbia University in New York City, reckons that the response to the current outbreak has been relatively swift and effective. At the start of the latest epidemic, in February, the Hong Kong Department of Health traced seven of those initially infected to the same hotel in Kowloon.

And the spread of the disease seems to have been partly stemmed by keeping suspected patients in isolation. So far it is mainly close family members and hospital workers who have been infected. Even so, the situation is "damned scary", concedes influenza researcher Robert Webster of St Jude's Children's Research Hospital in Memphis, Tennessee.

Nature News Service / Macmillan Magazines Ltd 2003

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