Handle with care: Brucella abortus. Credit: PHOTOTAKE/ALAMY

More than 900 people working in 254 labs around the United States and Canada might have been exposed to modified Brucella abortus last autumn, because of their failure to follow proper handling procedures for the bacterium, the Atlanta Journal-Constitution has reported.

Brucella abortus primarily causes disease in cows, but it can also make people ill. It was posted to 1,316 clinical laboratories in a joint exercise ? led by the College of American Pathologists, the Centers for Disease Control and Prevention, and the Association of Public Health Laboratories ? to test the labs' procedures for dealing with suspected bioterrorism agents.

Also last week, watchdog groups reacted with outrage to news that virologist Yoshihiro Kawaoka is working with a modified Ebola virus in a biosafety level-2 (BSL-2) laboratory at the University of Wisconsin in Madison, but has not consulted the US National Institutes of Health (NIH) about the work. The NIH previously overruled a decision by the university to allow Kawaoka to work with Ebola genes in a BSL-3 lab, saying that it wanted him in a BSL-4 one.