Herpes Simplex Virus (HSV) - Herpes Viruses

Herpes Viruses

·        All Herpes viruses exhibit latency

Herpes Simplex Virus (HSV)

·        Manifestations: systemic (fever, sore throat), gingivostomatitis (ulcers with yellow slough – cold sores), meningitis (uncommon, self-limiting), encephalitis (fever, fits, headache, dysphagia, hemiparesis – do PCR on CSF sample – refer urgently)

·        Incubation: 2 – 25 days. Chronic infection is due to the virus remaining in the sensory nerve ganglia. Infectious period indeterminate ® contact isolation

·        Symptoms:

o  Blisters which become shallow painful ulcers, often preceded by itching or tingling

o  First episode may be accompanied by flu like illness, tender inguinal nodes and dysuria

o  Recurrences can be brought on by stress, fatigue, depression, immunosuppression and concurrent illness. Recurrences usually less severe and become less frequent

·        Diagnosis: clinical suspicion. Swab the base of an unroofed ulcer and refrigerate in viral medium. This will be painful. Culture negative doesn‟t exclude HSV as timing and collection technique important.

·        Serology possible, but not routinely used

·        Pathogenesis.  There are two antigenic types of Herpes Simplex Virus:

o  Type 1 is associated with lesions on the face and fingers, and sometimes genital lesions. Treat with zovirax (topical cream). Prevalence: 70% of population

o  Type 2 is associated almost entirely with genital infections, and affects the genitalia, vagina, and cervix and may predispose to cervical dysplasia. 10% of oral lesions caused by type 2. Prevalence: 10 – 15% of population (depends on population – more in high risk)

Type 1 Herpes Simplex Virus

·        Infection of fingers or thumb leads to a whitlow (vesicles coalesce)

·        Can infect eczematous skin ® eczema herpeticum

·        Children:

o  HSV1 the most common type in children.

o  Primary infection in childhood leads to gingivostomatitis – may lead to dehydration as child won‟t drink. May need NG tube

o  Dribbling can ® perioral spread

o  Auto-inoculation can ® conjunctivitis, genital lesions, skin infection with eczema (eczema herpeticum) can be severe

o  If neonate or immunocompromised can be life-threatening

o  Treatment: Oral analgesics (eg lignocaine) and Paracetamol.  Acyclovir

Genital Herpes (type 2)

·        Description:

o   Painful, recurrent condition. 

o   Male – anus or penis – small grouped vesicles and papules + pain, fever, dysuria. Dysuria may be severe enough to cause urinary retention

o   20% may have it, but 20% are asymptomatic and 60% mild or unrecognised

·        40% caused by type 1, 60% by type 2

·        Transmission: spread through skin-to-skin contact, usually when skin is broken or lesions present, but asymptomatic viral shedding a possible route of transmission. Neonatal transmission is rare (1 in 10,000 live births), but carries risk of ophthalmic infection Þ caesarean section indicated if active blisters at delivery

·        Prevention of genital herpes: Condoms with new partner (although doesn‟t eliminate risk). Avoid sex during an outbreak

·        Can have extra genital lesions on thighs and buttocks. Can ® radiculoneuropathy ® urinary retention/constipation

·        Treatment of Genital Herpes (type 1 or 2):

o   Acute: Acyclovir 200 mg 5 times daily for 5 days.  Topical creams not effective.  Symptomatic 

o   treatment: salt bathing, local anaesthetic creams, oral analgesia, oral fluids. Counselling and follow-up important – written information for patients and partners, Herpes Helpline (0508 11 12 13) 

o   Suppressive Therapy: Where frequent outbreaks or psychological morbidity. Acyclovir 400 mg BD for up to a year. Can reduce viral shedding by up to 95%

o   Can be devastating.  Refer to counselling at Sexual Health Service

·        Complications: 

o   ­Risk of AIDS transfer

o   Erythema Multiforme

o   Neonatal Herpes: 1 % transmission but 50% mortality

o   In pregnancy:

§  If first primary episode: miscarriage, prem labour

§  If recurrent, tiny risk for baby

§  If lesions at delivery then Caesarean