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No one is sure how an active strain of tularaemia bacteria managed to infect university lab workers. Credit: CDC

The accidental infection of three Boston University researchers with dangerous bacteria is raising questions about the US expansion of biodefence labs.

Massachusetts-based Boston University has been chosen by the National Institutes of Health to host one of two major research and containment centres for deadly pathogens. The university is planning to build a National Biocontainment Laboratory in a well populated area of south Boston, much to the dismay of residents. The US$128-million facility will be part of a system of labs being developed across the United States.

But last year, experiments by researchers at Boston University's medical campus caused three of them to get tularaemia infections. “This is symbolic of what can happen,” says Boston University epidemiologist David Ozonoff, who switched last year from supporting the biodefence lab to opposing it.

The researchers thought they were handling the tularaemia bacterium, which could be used for bioterrorism, in its deactivated form. In May, two of the researchers became ill with respiratory infections. No one suspected the cause until October, after a third researcher had sickened. The US Centers for Disease Control and Prevention, based in Atlanta, Georgia, was notified about the cases in mid-November.

Since then, the patients have recovered. But the handling of the case has caused outrage and stirred opposition to the biodefence lab. The university delayed reporting the incidents to state health authorities by 12 days, although state law requires that such cases be reported within 24 hours. And the university — along with city, state and federal officials — did not publicly disclose the infections until last week. This meant the issue was not discussed last autumn during the planning process for the biodefence lab.

“If there was any risk outside these three infected people, we would have made a general announcement in a heartbeat,” says Thomas Moore, acting provost of Boston University's medical campus, pointing out that tularaemia cannot be passed from person to person. He says that announcements were delayed until after internal investigations, and adds that the infections were not considered relevant to public debate over the biodefence lab, because that will have better containment facilities.

In the aftermath of the incident, Boston University's chief of infectious disease at the time, Peter Rice, was removed from his position. And Boston health officials say they are preparing an education campaign for lab personnel, to ensure that safety regulations are followed. It is thought that the researchers who became ill may have been working without the required fume hood.

But details of the case continue to raise questions. For instance, Paul Mead, an epidemiologist at the Centers for Disease Control and Prevention, says his agency has been unable to determine how and where the non-infectious sample became contaminated with a wild, infectious strain. “This is a bit of a freak event,” says Mead. Perhaps tularaemia-contaminated rabbit blood was used as a culture medium, he says. Genetic testing of material may pin down the source.

Officials at the National Institute of Allergy and Infectious Diseases, which will fund the Boston biodefence lab and the national system, declined to comment on the incident as an investigation is still under way.