Crabs are parasites. Crabs are often referred to as public lice and are not to be confused with body lice. The scientific name for crabs is Pediculus pubis. Crabs need blood to survive, but they can live up to 24 hours off a human body.
Crabs have three very distinct phases.
The first phase is the egg. The second phase is the nit. The third phase is called the louse, and is the parasite that causes itching. In the United States, there are an estimated 3 million cases of crabs every year. Non-sexual transmission You can get crabs from sleeping in an infested bed or using infested towels.