CDC testing found low levels of live anthrax in all 22 samples it had received from affected laboratories.
The samples were from labs that had received supposedly inactivated material from the Army Proving Ground in Dugway, Utah.
“We are assuming any samples that were derived from lots prepared at Dugway contain live material,” said CDC spokesman Jason McDonald. “There is no need to test those samples further. The priority is to secure the samples and destroy the material.”
Accordingly the CDC has instructed any laboratories that may have received anthrax sample shipments from Dugway between 2004 and 2015 to destroy their existing samples.
“If the labs are able, destroy the samples in accordance with standard procedures and with an approved method (e.g., autoclave). The destruction must be completed within 7 days and evidence of the destruction provided to CDC,” said McDonald.
A third option would be for labs classified as a select agent registered entity to register their sample with the Federal Select Agent Program and retain it.
Meanwhile the military continues to test the more than 400 lots of supposedly dead anthrax it keeps at four military facilities. Some 11 of 91 lots have tested positive for anthrax, and all of those are from the Dugway facility.
Tracing the distribution path of those lots to laboratories has led to the increasing number of affected laboratories that may have received live anthrax.
Pentagon officials stress that there is no threat to the general public from the shipments of live anthrax pointing to the secure packaging of samples which were sent by Fed Ex.
At a Pentagon briefing two weeks ago senior Pentagon officials said that the amounts of anthrax being shipped to laboratories for research purposes contained levels of anthrax that were significantly less than the amount needed to infect a healthy person.
No lab workers have shown any symptoms of possible anthrax infection, though 31 individuals have been protectively receiving antibiotics as a precautionary move.