2.HSV (herpes simplex virus )HSV-1 and HSV-2 are two members of the human Herpesviridae family, a set of viruses that produce viral infections in the majority of humans.Both HSV-1 (which produces most cold sores) and HSV-2 (which produces most genital herpes) are very common and contagious. They can be spread when an infected person begins shedding the virus.