Congenital Zika

Background

• Infection with Zika virus
• Mostly transmitted by mosquitoes (mainly Aedes aegypti), but can be sexually transmitted
• Present in most of South and Central America including the Caribbean, sub-Saharan Africa, the Indian subcontinent, southeast Asia, and the Pacific islands
• Transmission
  • Detectable in serum of pregnant women for 10 weeks after symptom onset
  • Detectable in semen for up to 188 days after symptom onset (but only 69 days for replication-competent virus)
    • Longest documented duration from symptom onset to sexual transmission is 32 to 41 days

Trimester	Any Microcephaly	Congenital Zika Syndrome
first	10%	7%
second	3%	1%
third	4%	1%
overall	6%	3%

Clinical Manifestations

• Cranial morphology due to a disruption in the fetal brain sequence
  • Severe microcephaly
  • Overlapping cranial sutures
  • Prominent occipital bone
  • Redundant scalp skin
• Brain anomalies
  • Diffuse CNS calcifications, primarily subcortical
  • Ventriculomegaly
  • Polymicrogyria with cortical thinning
  • Hypoplasia of the corpus callosum
  • Decreased myelination
  • Hypoplasia of the cerebellar vermis
• Ocular anomalies (25 to 55%)
  • Chorioretinal atrophy or scarring
  • Focal pigmentary retinal mottling
  • Optic nerve atrophy
  • Microphthalmia, cataracts, and intraocular calcifications
• Congenital contractures (5 to 15%)
  • Arthrogryposis
  • Club foot
  • Congenital hip dislocation
  • Other contractures, usually bilateral

Diagnosis

• Testing is only indicated for returned travellers with compatible symptoms
  • CATMAT recommends against routine testing of asymptomatic pregnant women
• Molecular testing is the mainstay of diagnosis
• Serology also possible

Prevention

• For asymptomatic men and women: no recommendations
• For women who have confirmed infection: wait 2 months after returning from the risk area before trying to conceive
• For men who have confirmed infection: wait 3 months after returning from the risk area before trying to conceive
• For men with compatible symptoms or confirmed infection and a pregnant partner: use barrier protection for the duration of pregnancy

Further Reading

• CATMAT Zika Virus Prevention and Treatment Recommendations