Herpes simplex virus

Question 1

Definition

Answer 1

DEFINITION: disease resulting from HSV1 or HSV2 infection

Question 2

Causes

Answer 2

Transmitted via close contact (e.g. kissing, sexual intercourse) with an individual that is shedding the virus

Pathophysiology

• After primary infection, the virus will become dormant (within nerve ganglia)
• Reactivation may occur in response to physical and emotional stresses or immunosuppression
• The virus causes cytolysis of infected epithelial cells leading to vesicle formation

Question 3

Epidemiology

Answer 3

90% of adults are seropositive for HSV1 by 30 yrs

35% of adults > 60 yrs are seropositive for HSV2

More than 1/3 of the world population have recurrent HSV infections

Question 4

Symptoms

Answer 4

HSV1 - primary infection is often asymptomatic

• Possible symptoms of primary HSV1 infection:
• Pharyngitis
• Gingivostomatitis (eating might be painful)

Herpetic whitlow (abscess at the end of the finger caused by infection with HSV - it is very painful)

• Symptoms of reactivation of HSV1:
• Prodrome of perioral tingling and burning
• Vesicles appear - they will ulcerate and crust over
• Complete healing within 8-10 days

Symptoms of HSV2:

• Painful blisters and rash in the genital, perigenital and anal area
• Dysuria
• Fever
• Malaise

Symptoms of HSV encephalitis:

• Usually caused by HSV1 so causes HSV1 type symptoms

Symptoms of HSV keratoconjunctivitis

• Watering eyes

Photophobia

Question 5

Signs

Answer 5

HSV1 Primary Infection

• Tender cervical lymphadenopathy
• Erythematous, oedematous pharynx
• Oral ulcers filled with yellow slough (gingivostomatitis)
• Herpetic whitlow

Herpes Labialis (reactivation affecting the mouth)

• Perioral vesicles/ulcers/crusting

HSV2

• Maculopapular rash
• Vesicles
• Ulcers
• All of these are found on the external genitalia, anal margin and upper thighs
• Others: inguinal lymphadenopathy, pyrexia

HSV2 Encephalitis

• Signs of encephalitis

HSV Keratoconjunctivitis

• Dendritic ulcer on the iris (better visualised with fluorescein)

Question 6

Investigation

Answer 6

Diagnosis is usually CLINICAL

Vesicle fluid can be sampled and sent for electron microscopy, PCR