Virus that causes blister-like open sores, usually on the mouth or genitals of the infected person.

Herpes simplex virus (HSV) exists in two known forms. HSV type 1 causes sores to erupt near the mouth; HSV type two causes sores to erupt on the genitals. HSV type 1 sores are referred to as oral herpes, cold sores, or fever blisters. Oral herpes is one of the most common viral diseases of childhood.

Prenatal stage. Prior to birth, fetuses of mothers with genital herpes are at risk for birth defects. An active genital herpes sore at the time of birth can cause extremely serious results, including blindness, birth defects, and even death. Cesarean section is advisable for mothers with active herpes eruptions at the time of delivery.

Newborn infants. Newborn babies have their mother's antibodies providing them immunity against herpes simplex virus until around six months of age.

Infancy, Toddlerhood, and School- Age Children