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Herpes simplex virus HSV 1 and HSV 2 Transmission HSV 1- transmission is mainly through contact with saliva HSV 2- sexual intercourse is considered to be the main route of transmission, although vertical transmission is important in neonates.
The incubation period is between 2 to 4 days.
Clinical presentation Herpes labialise It is caused by HSV 1. The characteristic vesicular lesions appear in oral mucosa and the skin around the lips. The ulcer is usually painful. Recurrence is common after exposure to sun light or during physical stress or febrile illness.
Genital herpes It mainly transmit through sexually contact, and in addition it can be transmitted by self-inoculation. Vesicular rash and painful ulcers around the genital organs are the common features. In one third of the patient with primary infection, the infection may involve the CNS-patients may experience mild meningitis or encephalitis. Recurrence is uncommon after infection with HSV 1. On the contrary recurrent infection is commonly due to HSV 2 .
Neonatal herpes HSV 2 is the common cause of neonatal herpes as vertical transmission is the main route of infection in neonates. Staff and family members with cold sores can be source of infection, and with these modes of transmission, HSV 1 is much more common than HSV 2. HSV infection in neonates may present with muco-cutaneous lesions, pneumonia, hepatitis, encephalitis or disseminated infection. Infection involving the CNS and disseminated infections havehigh mortality and long term morbidity.
Herpes encephalitis The main causes of encephalitis in Western Europe is infection with HSV 1. Characteristically patient present with acute onset of fever, headache, seizure and loss of consciousness. It causes high mortality if not treated early. Recurrence is not uncommon even after weeks of treatment.
Rare complications
Investigation
CT scan / MRI are useful for patients with encephalitis.
Diagnostic tests
Vesicular lesion or ulcer Swab for IF and virus isolation. PCR can also be used to diagnose infection with HSV. If there is no active lesions, serological test for HSV IgM can be used to diagnose primary infection or first episode. However HSV IgM is not uncommon in reactivation.
Encephalitis Lumbar puncture can be carried out if there is no contraindication. CSF- HSV DNA PCR. PCR is very sensitive test however it can give a false negative result if the CSF is taken in the first 2 days.
Neonatal Herpes Swabs from the vesicle or ulcer for IF and virus isolation. EDTA blood and CSF for HSV DNA PCR are appropriate samples.
Screening v Transplant patients HSV IgG – it is not routinely done by most laboratories. v GUM patient Type specific HSV IgG testing is carried out to identify discordance however in practice it is not that useful.
HSV antibody tests ________________________________________________________________________________________________________ HSV IgM HSV IgG Primary infection + + Non-primary infection _ + Reactivation/ re-infection _ +
Treatment
Oral acyclovir is effective to shorten the duration of viral shedding. Valacyclovir have better bioavailability. Famcyclovir is another alternative to treat genital herpes. For the dose, look under antiviral sections. For recurrence genital herpes, acyclovir suppressive therapy should be used.
Hospital care Patients with encephalitis, and newborns with herpes infections should be treated with intravenous acyclovir.
Prevention
Individual care Safe sexual practise- condoms can prevent sexual transmissions. Public health workers Contact tracing is important not only to control transmission of herpes simplex but also other sexually transmitted diseases. Hospital Care Health care workers and family members with active herpetic lesions should avoid direct contact with newborn babies. Prophylaxis with acyclovir is recommended in transplant patients to prevent HSV reactivation. There is no vaccine.
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Date this page is updated: 04/03/2007 23:13:30 www. virologynotebook.co.uk
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