Health and Fitness

HSV-1 and HSV-2 are distributed worldwide, and herpes infection occurs in both developed and developing countries. Animal vectors of human HSV infections have not been described, and humans remain the sole reservoir for transmission to other humans. Virus is transmitted from infected to susceptible individuals during close personal contact. There is no seasonal variation in the incidence of infection. Because HSV infection is rarely fatal, and HSV establishes latency, more than one-third of the world’s population has recurrent HSV infections and, therefore, the capability of transmitting HSV during episodes of productive infection.
In developing countries, seroconversion occurs early in life. In lower socioeconomic populations, approximately one-third of children have serological evidence of HSV infection by 5 years of age; this frequency increases to 70%-80% by early adolescence. Predictably, middle-class individuals acquire antibodies later in life, such that seroconversion over the first 5 years occurs in 20% of children, followed by no significant increase until the second and third decades of life, at which time the prevalence of antibodies increases to 40%-60%.

In conclusion, geographic location, socioeconomic status, and age influence the frequency of HSV-1 infection. The seroprevalence of HSV-1 and HSV-2 infections has been redefined by using type-specific serological assays and sera obtained from the randomized National Health and Nutrition Examination Survey. By the age of 5 years, over 35% of African American children are infected by HSV-1, as compared with 18% of Caucasian children. Through adolescence, the prevalence of antibodies to HSV-1 is approximately twofold higher among African Americans than among Caucasians.
Although most genital HSV infections are caused by HSV-2, an ever-increasing proportion is attributable to HSV-1. The distinction in virus type is not insignificant, since genital HSV-1 infections are usually both less severe clinically and less prone to recur. The number of new cases of genital HSV infections has been conservatively estimated to be about 500,000 annually, and approximately 40 million to 60 million Americans are infected latently with HSV-2. Outbreaks are commonly accompanied by pain, itching, or burning. Some experience enlarged lymph nodes, muscle pain, and fatigue with genital herpes.