Basic facts on herpes
Herpes can refer to several different types of herpetic viruses, but most commonly this term refers to herpes simplex I (HSV-1, also called oral herpes) and herpes simplex II (HSV-2, also called genital herpes). This is somewhat misleading because HSV-1 can cause lesions on the genitals and HSV-2 can cause oral lesions. However, most oral herpetic lesions are caused by HSV-1 and most genital herpetic lesions are caused by HSV-2.
Infection with HSV-1 occurs more frequently and at a younger age than HSV-2. Over 90% of adults have antibodies to HSV-1 by their late 20's. Antibodies indicate a prior or current infection to the particular infectious agent. Antibodies to HSV-2 are usually not detected until puberty. 10-40% of the general U.S. population has antibodies to HSV-2. In obstetrical clinics, 20-30% of pregnant women possess HSV-2 antibodies, but only 10% report a past history of genital lesions.
Contact with active ulcerative lesions or asymptomatic patients who are excreting herpes virus can result in transmission. Asymptomatic salivary excretion of HSV-1 has been reported in 2-9 percent of adults and 5-8 percent of children. The efficiency of transmission is greater during symptomatic versus asymptomatic periods of viral excretion.
The clinical manifestations and course of HSV depend on the anatomic site of the infection, the age and immune status of the person, and the antigenic type of the virus. First episodes of HSV disease are frequently accompanied by systemic signs and symptoms, involve both mucosal and extramucosal sites, have a longer duration of symptoms, a longer time from which virus is isolated from lesions, and a higher rate of complications than recurrent episodes. Both viral subtypes can cause oral-facial and genital infections that are clinically indistinguishable, however, the recurrence rates are different.
Clinical symptoms and signs of oral-facial HSV infection include fever, malaise, muscle aches, inability to eat, irritability, and cervical lymph node swelling which may last from 3-14 days. Lesions may involve the soft palate, gingiva, tongue, lips and facial area.
First episodes of genital herpes are characterized by fever, headache, malaise, and muscle aches. Locally, pain, itching, dysuria, vaginal and urethral discharge, and tender enlarged lymph nodes may be present. Lesions may be present in various stages including vesicles, pustules, and ulcers. Cervical and urethral involvement is seen in 80% of women during the first episode. Recurrence rates for HSV-2 genital infections are an average of four in the first 12 months, and 90% will have at least one recurrence in 12 months. Whereas, patients with HSV-1 genital infections will have an average of only one recurrence in the first 12 months, and only 55% will have at least one recurrence in 12 months.