There are two different strains or types of the herpes simplex virus. Herpes simplex virus type 1 (HSV-1) and type 2 (HSV-2). They are both common infections and have the ability to cause oral or genital infections. The two types are related through the sores they cause, but they do have many differences.

Transmission of Herpes Simplex Type 1 and Type 2

HSV-1 is more common than HSV-2 and is usually transmitted during childhood mainly through contact with infected saliva. It affects the lip, mouth and face by causing cold sores or “fever blisters.”

HSV-2 is transmitted through genital secretions, mostly which occur during sexual encounters. Although rare, it can be passed from an infected mother to her unborn baby. Lesions and sores usually come about in or on the genitals.

With both types of the virus, the chances of transmitting it to another person is much greater when the symptoms are active than when they are dormant, but the virus can still be passed on when the signs are inactive.

Even though an individual may have been infected by HSV-1, or oral herpes, it is still possible for that type to cause genital infections as it is still possible for HSV-2, genital herpes, to cause oral infections. However HSV-1 is the cause of most oral and facial herpes and HSV-2 is the cause of most genital herpes.

Primary Herpes Infections

Because most cases of herpes simplex virus type 1 take place during childhood, many people do not recall having the primary infection. Even if they occurred after childhood, most cases are classified as subclinical- meaning the symptoms were not noticed and the infection went untreated. The infection may cause no symptoms or mild symptoms that include the fever followed by swollen gums and the formation of white blisters on the tongues and insides of the cheek which eventually burst resulting in yellow ulcers. The whole process usually lasts between 10 to 14 days.

Like Type 1, Type 2 does not always exhibit obvious initial signs that show an individual he or she has been infected. In fact after the transmission, most individuals have none or few symptoms from the infection and are not aware they have been infected by the virus. If the first signs do appear, they usually appear within two weeks after the virus has been transmitted, and consist of flu-like symptoms and ulcers that appear on the genitals. They can last up to three weeks if they are not treated.

First infections may be mild and go unobserved, but they are often more severe than the recurrences that follow. Initial infections of Type 2 are generally more obvious than the initial infections of Type 1. Even though the first infection for most people is mild, it is possible for it to develop. If it does, then the infections that follow it may more severe than the first.

Recurrent Herpes Infections

After the initial infection, the body develops resistance to the virus, and it lies in a dormant state in or around the nerves that supply sensation to the skin. However the body’s defense is not enough to fully protect against any future attacks. So when the immune system is low, the virus is reactivated and goes through an outburst in which it grows down the nerves and out into the open skin. There it multiplies and causes the skin to become infected. After a certain amount of time, the virus dies and goes back down the nerve fibre and becomes dormant again.

Both types become active by stress, the sun, a fever, hormonal changes, trauma, or nothing at all and tend to recur in the same place. Reoccurrences for Type 1 infections mostly appear specifically on the mouth. Reoccurrences for Type 2 usually appear on or around the sexual organs or buttocks.

The chances of the virus recurring are higher if it was caused by HSV-2 than if it was caused by HSV-1.

Oral herpes can occur every month or only one or two times a year. People diagnosed with genital herpes usually have outbreaks four to eight times during one year. Over time the frequency and pain of the sores decrease for both types.

Sources:
http://www.cdc.gov/std/Herpes/STDFact-Herpes.htm
http://www.healthfinder.gov/scripts/SearchContext.asp?topic=313
http://dermnetnz.org/viral/genital-herpes.html