Herpes simplex virus-2, also known as HSV-2, is one of the most common sexually transmitted infections throughout the world and is exclusively sexually transmitted, causing genital herpes. HSV-2 has caused a significant disease burden globally, with the World Health Organisation (WHO) reporting more than 23 million new cases each year. Infection with HSV-2 is lifelong.
Introduction to the Herpes Virus
Herpes is a contagious viral infection caused by the herpes simplex virus (HSV). There are two types of herpes simplex virus infections. HSV-2 mainly responsible for genital herpes. The herpes virus is a large, enveloped DNA virus that infects a wide range of vertebrates. It is highly capable of establishing lifelong latent infections. Humans are the only natural host and sole reservoir for virus transmission.
HSV Type 1 (HSV-1)
HSV-1 spreads through direct personal (skin to skin) contact and causes cold sores or blisters in the mouth and can spread to the genitals via oral sex.
HSV Type 2 (HSV-2)
HSV-2 is usually the more common causative agent and is responsible for up to 80% of genital infections. It is spread through skin to skin contact and sexual activities. HSV-2 is also more contagious than HSV-1 and can spread to uninfected individuals without the presence of an open infectious sore. HSV-2 recur more often than HSV-1.
Most people who acquire herpes get it from an asymptomatic individual. HSV can spread through direct skin contact with infected sores and passed via the saliva of an infected person. Unprotected sexual intercourse carries the biggest risk of infection. Viral shedding occurs from obvious lesions such as blisters and ulcers and apparent intact skin and mucous membranes.
The incubation period for the virus is 2 to 14 days.
Women usually develop sores around the vagina, cervix, external genitalia, buttocks and anus. Men on the other hand, develop sores on the penis, scrotum, anus, thighs and buttocks.
Common symptoms that can last anywhere from 10 days to a month include:
- Itching around the genital area or inner thighs after exposure to an infected partner
- Small red bumps, blister and open sores (ulcers) around the genitalia, including the anus and surrounding areas that may rupture
- Pain passing urine (dysuria)
- Swollen lymph nodes in the groin area
- Fever and flu-like symptoms
- Painful oozing sores
Reactivation from HSV latent infection
The herpes simplex virus, unlike other venereal diseases, are harder to remove from the body and resides in the nerves (sensory neurones). Symptoms can always reappear in recurrent herpes, and the virus may attack the body even after many years of the initial infection.
Recurrent herpes may be triggered by hormonal changes, illness, skin trauma, physical and mental stress. The mechanisms underlying virus reactivation are unknown. The immune response plays an important role in recurrence as immunosuppression increases the severity of lesions (ulcers). Those who are immunocompromised are highly susceptible to reinfection, especially in patients with the human immunodeficiency virus (HIV).
HSV infection is confirmed through laboratory confirmation of genital specimens. A swab is taken at the base of a lesion (usually a sore) of a person and the vesicles are usually unroofed with a small needle. The common diagnostic methods are:
- Polymerase chain reaction (PCR) Test: PCR is more sensitive than culture testing and does not require the live virus
- Culture: Cell culture can be used in a variety of cell lines but is less sensitive than PCR
- ELISA (enzyme-linked immunosorbent assay) or Western Blot analysis
HSV typing is also recommended for patients who have been infected with the virus for the first time to guide management.
Antibodies to herpes can be detected as early as 2 to 3 weeks after the first exposure but can take up to 16 weeks to develop in certain individuals. Over time, the level of antibodies can decrease in some individuals.
Pregnant mothers with genital herpes can pass the congenital herpes to their unborn child via the birth canal that may result in blindness, brain damage (encephalitis or meningitis), mental disabilities and morbidity.
An infected person with genital herpes also carries an increased risk of urinary retention and contracting other types of sexually transmitted diseases such as chlamydia, gonorrhoea and acquired immune deficiency syndrome (AIDS).
HSV-2 and HIV co-infection
HSV-2 co-infection in HIV-infected individuals has been shown to increase HIV shedding in genital secretions. HSV-2 infection can increase the risk of HIV transmission by up to 3-fold. In HIV infected individuals who are not treated with HIV therapy, genital herpes infection can be prolonged and require higher doses of antivirals to clear the infection.
There is no cure for herpes but antiviral oral medication (oral acyclovir) and topical anaesthetic treatments can help to treat sores and reduce pain.
Antivirals help to reduce the severity and duration of clinical episodes, decrease the frequency of recurrences and reduce the level of viral shedding. They also help to limit infection by reducing the risk of transmitting the infection to sexual partners and helps to decrease mother to child transmission.
The use of a condom can help to prevent the transmission of the disease of up to 50 percent.
Herpes can be controlled through educating the public, counselling, abstinence and refraining from sex during episodic infections.
Genital herpes is the leading cause of genital ulcers. HSV-2 can be passed on without any symptoms and the best way to avoid genital herpes is to avoid any direct skin-to-skin contact.