Herpes

Oral Herpes Overview The herpes simplex virus affects only humans. Mouth sores most commonly occur in children aged 1-2 years, but they can affect people at any age and any time of the year. People contract herpes by touching infected saliva, mucous membranes, or skin. Because the virus is highly contagious, most people have been infected by at least 1 herpes subtype before adulthood. After the herpes virus infects you, it has a rather unique ability to proceed to 3 stages. - Primary infection: The virus enters your skin or mucous membrane and reproduces. During this stage, oral sores and other symptoms, such as fever, may develop. (The virus may not cause any sores and symptoms. You may not know that you have it. This is called asymptomatic infection). – Latency: From the infected site, the virus moves to a mass of nervous tissue in your spine called the dorsal root ganglion. There the virus reproduces again and becomes inactive. – Recurrence: When you encounter certain stresses, emotional or physical, the virus may reactivate and cause new sores and symptoms.

Causes Herpes simplex (HSV) is a DNA virus that causes herpes. It has two types; HSV 1 and HSV 2. HSV 1 (oral herpes) usually causes infections on the lips or mouth in the form of cold sores or fever blisters and also causes painful sores on your lips, gums, tongue, roof of your mouth, and inside your cheeks. It also can cause symptoms such as fever and muscle aches. HSV 2 (genital herpes) usually causes sores and blisters in the genital area. However, virus from the mouth can infect the genitals and virus from the genitals can infect the mouth. Herpes virus can also infect other parts of the body. Both viruses can live inside nerve cells and cause symptoms that occur again and again.

Means of Transmission Genital herpes is spread by direct contact with an infected person. Sexual intercourse and oral sex are the most common methods of spreading genital herpes. Any type of skin-to-skin contact, however, is capable of spreading herpes. Herpes can also be transmitted from person to person through kissing. It is also transmitted from mother to baby during childbirth

Global Impact The global burden of HSV-2 infection has never been systematically estimated. In common with other sexually transmitted infections, any estimate based on the number of reported cases of genital herpes will underestimate the popularity of infection, since most people with HSV-2 are unaware they are infected. However, diagnostic tests can detect the presence of antibodies to HSV-2 with a high degree of precision, and since infection with HSV-2 is lifelong, diagnose prevalent HSV-2 infection. Several studies have been conducted to estimate the prevalence of antibodies to HSV-2 in particular settings, either using blood collected specifically to measure HSV-2 seroprevalence, or using residual blood collected for other purposes. The nature, size and selection of the samples vary widely from study to study. A small number of studies are large in size and examine frequency in the population as a whole. More commonly, studies are relatively small in size and limited to a specific group.

A study in 2002 systematically reviewed the available popularity data for HSV-2 by country, but did not pool these data to produce frequency estimates for entire regions, nor attempt to calculate numbers of individuals with the widespread HSV-2 infection. Furthermore, this study only looked at prevalence data and did not consider incident infections. Using tables of seroprevalence data compiled in this review and in our update of this review, and using recently published data, pooled values of the HSV-2 prevalence by age and gender for all areas of the world are calculated. Model fits are then performed to estimate the numbers of people with prevalent HSV-2 infection, and the numbers of new cases of HSV-2 infection, for the year 2003.