Since small pox has been eradicated, the pox virus family no longer is a major threat to humans. Occasionally, infection with monkey pox, cow pox, or ORF (contagious pustular dermatitis) may occur. However, the only other specifically human virus is molluscum contagiosum, an uncommon skin disease that mainly affects children and young adults. Lesions which look similar to those caused by herpes simplex virus are spread by direct skin contact in children and by sexual transmission in adults. The number of lesions can range from one to hundreds, and are usually found on the face, scalp, arms, legs, and genitalia. The incubation period varies between 14 and 50 days. The disease may last for several months, but is self-limiting. It occurs worldwide, with higher prevalence in parts of Zaire and Papua New Guinea.