Genital herpes is caused by infection with herpes simplex virus (HSV). There are two types of HSV, HSV-1 and HSV-2, both of which belong to a wider group called Herpesviridae. Another well-known virus in this group is varicella zoster virus, which causes chicken-pox and shingles. In general:
HSV-1 is acquired orally, causing cold sores.
SV-2 is acquired during sexual contact and affects the genital area.
Although genital herpes used to almost always be caused by HSV-2 infection, HSV-1 is accounting for an increasing number of cases of genital herpes in developed countries. Only around 10-25 percent of people infected with HSV-2 are aware they have genital herpes. This is because genital herpes will often produce mild symptoms or no symptoms at all (asymptomatic infection). As a result, many cases of genital herpes go undiagnosed and frequently people unknowingly pass the virus on to their sexual partners.
If symptoms do occur, they will usually appear 2 to 7 days after exposure and last 2 to 4 weeks. Both men and women may have one or more symptoms, including:
- Itching or tingling sensations in the genital or anal area;
- small fluid-filled blisters that burst leaving small painful sores (seeSTD pictures);
- pain when passing urine over the open sores (especially in women);
- headaches;
- backache;
- flu-like symptoms, including swollen glands or fever.