The U.S. Centers for Disease Control and Prevention announced today that up to 75 of its scientists may have been exposed to live anthrax bacteria in its laboratories in Atlanta. According to Reuters, the scientists were exposed after staff at a high-level biosecurity lab failed to follow the proper procedures to render the live anthrax bacteria inactive. So far, the CDC reports, none of the potentially exposed staff has reported any symptoms.

Staff beyond the high-level lab became exposed when the anthrax samples were transferred to a lower-level lab that, believing the bacteria to be inactive, were not properly protected against airborne exposure. From the Associated Press:

The safety lapse occurred when a high level biosecurity lab was preparing anthrax samples. The samples were to be used at lower security labs researching new ways to detect the germs in environmental samples. The higher security lab used a procedure that did not completely inactivate the bacteria.

Workers in three labs who later came into contact with these potentially infectious samples were not wearing adequate protective gear because they believed the samples had been inactivated. Procedures in two of the labs may have spread anthrax spores in the air.

Per Reuters, inhaling anthrax spores can be especially dangerous, with a high likelihood of death once illness reaches the second stage of symptoms:

In inhalation anthrax, bacterial spores enter the lungs where they germinate before actually causing disease, a process that can take one to six days. Once they germinate, they release toxins that can cause internal bleeding, swelling and tissue death.

Inhalation anthrax occurs in two stages. In the first stage, symptoms resemble a cold or the flu. In the second stage, anthrax causes fever, severe shortness of breath and shock. About 90 percent of people with second stage inhalation anthrax die, even after antibiotic treatment.

The potential exposure was discovered by CDC officials on Friday, June 13. Dr. Paul Meechan, director of the environmental health and safety compliance at the CDC, told Reuters that as many as seven staff members may have been directly exposed and that around 75 people have been offered a 60-day treatment regimen.

Meechan also told Reuters that an internal investigation has been launched and that the incident has been reported to the Federal Select Agent Program, "which oversees the use and transfer of biological agents and toxins that pose a severe threat to the public." He said it is currently unclear if the transfer of the active anthrax bacteria was accidental or intentional.

[Image via AP]