In Episode 7, they are only known to be found in Laboratory 51 of causing an outbreak. They are aggressive, they bite humans and wherever they had bitten, hair grows. What's worse is that shaving the hair off, only makes it grow longer. Luckily, the Protectors' scientists made a quick cure and was sent to Agent Brains to get Fred and her beards removed.
These bugs might have also represented lice, but instead of making you itchy, every time you shave the overgrowth of the hair it grows longer. One similarity is that they both can spread.