Both herpes simplex virus Type 1, or HSV-1, and herpes simplex virus Type 2, HSV-2, can cause genital herpes, though HSV-2 is most often the cause. A pregnant woman who has genital herpes can transmit the virus to her baby in utero or during birth and delivery. After birth, contraction can occur through direct physical contact with an infected person who is shedding the virus, even though at that time symptoms may not be visible, or through contact with infected bodily fluids, including saliva.
Neonatal Herpes
Herpes can transfer from a mother to a fetus across the placenta in an event called "vertical transmission." As the University of Washington Academic Medical Center notes, however, relatively few cases of vertical transmission have been reported. In their book "Congenital and Perinatal Infection," authors Cecelia Hutto and Gwendolyn B. Scott report that 5 percent of newborns who are infected with herpes contract the disease in utero. Those babies often exhibit a triad of complications including skin involvement, with scarring and active lesions; eye involvement, including malformation of the retina and abnormally small eyes; and neurological involvement, which can include hydranencephaly, a condition in which the brain's cerebral hemispheres are absent.
Infection During Delivery
About 85 percent of neonatal infections are passed from mother to baby during labor and delivery, according to Hutto and Scott. The most dangerous occur when a mother has recently contracted herpes and is experiencing a primary herpes infection during delivery. Primary infections are often asymptomatic, thereby increasing the risk of transference. The risks to the infant are significantly higher than if the mother had been infected long before delivery. Primary infections often have a longer period of shedding; for about three weeks, viral particles can shed from the mother's skin and mucosal membranes, compared with two to five days of shedding in recurrent outbreaks. Further, because the mother is recently infected, she has not built up neutralizing antibodies to pass on to her baby. The March of Dimes estimates that a mother with a primary infection has a 30 to 50 percent chance of passing the disease to her newborn during vaginal delivery. Complications for the newborn include seizures, respiratory distress, shock, jaundice and bleeding. The mortality rate of babies infected during labor and delivery is high---greater than 80 percent. Among the babies who survive, few do so without serious impairment.
Post-Natal Infection
Babies have immature immune systems, and when they become ill, they are often unable to effectively combat the disease, points out Lois McGuire, a nurse with the Mayo Clinic. Cold sores, or so-called "fever blisters," are caused by herpes, most often by HSV-1. An adult with herpes can infect a baby through normally harmless acts such as kissing the baby, or by touching the baby after having touched a herpes lesion. Though symptoms are not always present in older individuals, they're almost always apparent in infants.
Symptoms
When a herpes infection occurs within a month of birth, the disease is called "neonatal herpes." Symptoms can include blisters, or lesions, on the face and in and around the mouth, but the lesions may also occur elsewhere on the body. Lethargy, irritation and pain are also possible. Dehydration is a risk for babies with sores around the mouth, as these may discourage the infant from nursing.
Treatment
The prescription drug acyclovir, sold under the brand name Zovirax, is the only effective antiviral treatment for neonatal herpes, according to Skin Sight. It is available in liquid form and is approved for use in infants. Pain medication and anesthetic mouthwashes may be given to combat the pain.
References
- Skin Sight: Herpes Simplex Virus
- MayoClinic.com: Herpes and Pregnancy
- University of Washington Academic Medical Center: Neonatal Herpes
- "Congenital and Perinatal Infection"; Cecelia Hutto and Gwendolyn B. Scott; September 2005
- March of Dimes: Genital Herpes and Pregnancy
