Herpes SimplexHerpes simplex is one of the most common infections of mankind throughout the world. There are two main types of herpes simplex virus (HSV); type 1, which is mainly associated with facial infections and type 2, which is mainly genital , although there is considerable overlap. Both type 1 and type 2 herpes simplex viruses reside in a latent state in the nerves which supply sensation to the skin. With each attack of herpes simplex the virus grows down the nerves and out into the skin or mucous membranes where it multiplies, causing the clinical lesion. After each attack it "dies back" up the nerve fibre and enters the resting state again. First attacks of type 1 infections occur mainly in infants and young children, which are usually mild or subclinical. In crowded, underveloped areas of the world up to 100% of children have been infected by the age of 5. In higher socioeconomic groups the incidence is lower, for example less than half of university entrants in Britain have been affected. Type 2 infections occur mainly after puberty, often transmitted sexually. The initial infection more commonly causes symptoms. The virus can be shed in saliva and genital secretions from individuals without symptoms, especially in the days and weeks following a clinical attack. The amount shed from active lesions is 100 to 1000 times greater. Spread is by direct contact with infected secretions. Minor injury helps inoculate the virus, especially into the skin. The virus can be inoculated into any body site to cause a new infection, whether or not there has been a previous infection of either type. The source of the virus may be from elsewhere on the body especially in nail biters or thumb suckers. Examples of inoculation from external sources include lesions of the hand in health-care workers, facial lesions contracted in rugby scrums, and infection of a breast-feeding mother's nipples from the infected mouth of her baby. Following the initial infection immunity develops but does not fully protect against further attacks. However where immunity is deficient, both initial and recurrent infections tend to occur more frequently and to be more pronounced. Appearances of initial infections First infections may be mild and unnoticed, but when lesions develop the severity is generally greater than in recurrences. First infections with type 2 virus are generally more marked than first infections with type 1 virus. Herpetic gingivostomatitis (mouth infection) This is the most common clinical manifestation of type 1 infection. Most cases occur in children between the 1 and 5 years of age. After an incubation period of 4 to 5 days the symptoms begin with fever, which may be high, feeling generally unwell, restlessness and excessive dribbling. Drinking and eating are painful and the breath is foul. The gums are swollen and red and bleed easily. Vesicles (little blisters) occur in white patches on the tongue, throat, palate and insides of the cheeks. The white patches are followed by ulcers with a yellowish coating. The local lymph glands are enlarged and tender. The fever subsides after 3-5 days and recovery is usually complete within 2 weeks. Genital herpes Infection with type 2 occurs after the onset of sexual activity. Penile ulceration from herpetic infection is the most frequent cause of genital ulceration seen in sexual health clinics. The ulcers are most frequent on the glans, foreskin and shaft of the penis. They are sore or painful and last for 2 to 3 weeks if untreated. In the female, similar lesions occur on the external genitalia and the mucosae of the vulva, vagina and cervix. Pain and difficulty passing urine are common. Infection of the cervix may progress to a severe ulceration. Perianal herpes simplex can cause chronic ulceration in male homosexuals suffering from AIDS.
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