In September 2005 it was reported that three mice infected with Yesinia pestis, a select agent which causes plague, were missing from a University of Medicine and Dentistry, New Jersy (UMDNJ) lab. While it is most likely that the mice were missing due to a paperwork error or had been destroyed with other biohazardous waste, it was possible that the mice had actually escaped from the lab. The incident was reported in the media two weeks after the mice were discovered missing. By that time it was clear that there was no serious public health threat since the mice would only have survived and been able to transmit the disease for a maximum of three days. There was no evidence of human plague infection in Newark following the incident. The FBI Joint Terror Task Force investigated the incident and interrogated lab workers and the story was widely covered in the local press.

In February 2009 an additional incident of two plague infected mice missing from a UMDNJ lab was reported. In this case however, the missing mice were actually the carcasses of mice that died during an experiment and were bagged and placed in a freezer for storage until the experiment was completed and they could be incinerated. It is believed that the missing bag of mice was accidentally sterilized along with another bag. Once again, the FBI investigated and determined that there was no public health risk.