SARS Cases in Asia Show Labs' Risks

As Scientists Battle Diseases, Accidents Can Infect Public

Scientists still do not fully understand exactly where or how SARS emerged 18 months ago. But it is now clear that the most threatening source of the deadly virus today may be places they know intimately -- their own laboratories.

The recent announcement of nine cases of severe acute respiratory syndrome linked to China's National Institute of Virology brings to three the number of lab outbreaks of the disease in the past eight months. The three events -- including one in Singapore in September and another in Taiwan in December -- account for all but four of the known SARS cases since last year's epidemic was brought under control.

The Beijing incident, unlike the others, led to person-to-person transmission of the virus outside the lab. It caused one death and required quarantining about 200 people in two provinces to stop the virus from spreading. It was an epidemic "near-miss" and has led to calls for greater international monitoring of labs working on a virus that caused more than 8,000 illnesses and 774 deaths last year.

Together, the three SARS outbreaks have highlighted the unique hazards to public health that arise from accidental laboratory releases of germs that no longer exist -- or barely exist -- in the wild.

Such an event happened 26 years ago when the last cases of smallpox -- the only human disease ever eradicated -- occurred after a laboratory accident. Another one may have happened in 1977, when an influenza virus not seen for 27 years inexplicably reappeared and circulated worldwide. Leaders of the campaign to wipe out polio are working to ensure that such a thing never happens with that disease. They are already inventorying and urging destruction of global stocks of polio virus.

Laboratory workers can be infected in myriad ways, including needle sticks, animal bites, splashes in the mouth or eyes, and undetected inhalation of infected droplets. When a person recalls no definite exposure, in most cases the microbe somehow got into the air, usually because of poor lab technique and occasionally because of faulty equipment.

The number of fatalities in the United States from lab accidents is unknown, as there is no requirement to report lab accidents or cases of illness caused by them to government authorities. Thirty years ago, a University of Texas microbiologist attempted to count all known laboratory-acquired infections worldwide. He found 3,921 -- 4.2 percent of them fatal -- with most occurring before the 1960s.

Improvements in lab equipment and technique since, as well as development of vaccines against some of the more dangerous microbes, have greatly reduced lab hazards. But infections still occur, and not just from SARS. Russian health officials recently reported that a scientist working on Ebola virus at the Vector State Research Center of Virology and Biotechnology in Siberia died after sticking herself on May 5 with a contaminated needle. A team of experts from the World Health Organization is investigating China's lab-associated SARS cases. It has not announced its findings or any recommendations. But the problem goes far beyond what happened in the Beijing lab, some experts say.

"Does the WHO know how many laboratories in the world have this organism?" Robert Webster, a virologist at St. Jude Children's Research Hospital in Memphis, said of SARS. "It would seem to be time to collect this information. It really is time that the whole world, not just China, rounded up these things and put them away."

Webster has helped research numerous new strains of influenza, including the H5N1 strain of avian flu that killed millions of birds and 19 people last winter. He thinks lab stocks of dangerous influenza strains, as well as SARS virus samples, are a major but largely unrecognized threat to public health.