HSV

Question 1

HSV facts

Answer 1

1) DS DNA enveloped virus

2) Family Herpesviridae and subfamily
Alphaherpesvirinae

3) Incubation period: 1-26days

4) Spread by bodily secretions

Question 2

Primary vs latency and recurrent disease

Answer 2

• Primary infection
• HSV-1
• In early childhood: gingivostomatitis, fever, and marked submandibular lymphadenopathy
• In adolescent: pharyngitis and mononucleosis
• HSV-2: genital herpes with extensive bilateral vesicles, fever, inguinal lymphadenopathy, and dysuria
• Lesions caused by both HSV-1 and HSV-2 ulcerates and heal without scarring within 2 to 3 weeks
• Either type of virus can be found in either the genital or oral, mostly due to changes in sexual
  practice
• Latency and recurrent disease
• Virus establish latency in sensory ganglia: trigeminal ganglia for orolabial disease and lumbosacral
  dorsal root ganglia for genital disease
• Recurrent disease has milder and shorter time to lesion healing than primary episodes
• Genital HSV-2 recurrence are much higher than orolabial HSV-1

Question 3

Neonatal herpes and diagnosis

Answer 3

• The most serious consequence of HSV infection
• Occurs mostly during vaginal delivery when the infant is exposed to maternal secretions
• 3 distinct syndromes of peripartum infection:
  1) LOCALIZED to the skin, eyes, and mucosa or mouth (SEM) – 4 to 14 days of life
  2) DISSEMINATED present with septic appearance; liver function test (LFT) abnormalities – 4 to 14
  days of life

3) CNS – present 10 to 21 days of life with non-specific presentation

• In utero infection present with vesicles or scarring, eye disease, microcephaly or hydrocephalus
• Diagnosis
• PCR of lesions, CSF and blood when acute disease is suspected
• Obtain swabs of conjunctiva, nasopharynx, mouth and anus in asymptomatic infants born to women with active herpes
• Treatment: Acyclovir

Question 4

Other diagnosis

Answer 4

• Culture
• Antiviral phenotypic testing
• Conventional culture are examined for CPE within 5 days: Mink lung cells, rhabdomyosarcoma cells, MRC-5 and WI-38
  cells, Hep-2, and A549

Serology
* Only IgG test based on the type-specific HSV IgG accurately distinguish HSV-1 and HSV-2 antibodies

• IgG avidity test can be used to determine primary infection from recurrent episodes

*Don’t rely on IgM (can be false positive and can’t distinguish primary from recurrent infection)

Question 5

Treatment

Answer 5

• Primary:
  Acyclovir, valacyclovir, and famciclovir
• Mucocutaneous and genital herpes, for long-term suppression of recurrent
  episodes
• Selectively activated by HSV thymidine kinase and have minimal side effects
• Alternative agents: foscarnet and cidofovir
• Used for acyclovir-resistant infections