The scientific term for crabs is pubic lice, notes NHS. They are tiny parasitic insects that live on pubic hair, but can also be found in other areas with coarse body hair. Lice and eggs are visible to the naked eye.
Sexually transmitted pubic lice spreads when in close contact with someone who already has them, notes MedicineNet.com. However, pubic lice do not spread other sexually transmitted diseases, such as HIV. If you suspect you have pubic lice, you must visit your doctor for a check-up as soon as possible. The main symptom of pubic lice is itching in the genital area.