Question 1

What is Zika virus?

Accepted Answer

Zika virus is a flavivirus related to dengue, yellow fever and West Nile virus, transmitted primarily by Aedes aegypti mosquitoes. First isolated in 1947 from monkeys in Uganda's Zika forest, it caused sporadic human outbreaks until the 2007 Yap Island and 2013 French Polynesia outbreaks revealed its capacity for epidemic spread. The 2015-2016 pandemic — driven by a naive population encountering Zika for the first time in the Americas — affected 87 countries and territories.

Question 2

Why is Zika associated with microcephaly?

Accepted Answer

Zika virus can cross the placental barrier and infect fetal brain cells (neural progenitor cells), disrupting their development and causing cell death. This leads to malformed brain structures — with microcephaly being the most visible manifestation. The risk is highest with first-trimester infection; the virus appears to preferentially damage rapidly developing brain regions. Before 2015, microcephaly was not recognised as a Zika complication; the Brazil epidemic cluster of 3,500+ microcephaly cases triggered the scientific link.

Question 3

What is congenital Zika syndrome?

Accepted Answer

Congenital Zika syndrome encompasses: microcephaly (small head from brain underdevelopment); severe brain structural abnormalities (collapsed skulls, abnormal brain folding); eye defects (chorioretinal atrophy causing vision impairment); hearing loss; limb contractures; and postnatal growth restriction. Affected children require lifelong multidisciplinary support. The true global burden remains unknown because surveillance for congenital Zika is inadequate in most affected countries.

Question 4

How does Zika spread?

Accepted Answer

Primary route: bites of infected Aedes aegypti mosquitoes (day-biting, household breeding). Secondary route: sexual transmission (from infected men via semen for up to 3 months; from women during symptomatic period). Rare routes: blood transfusion, organ transplantation, potential mother-to-child during delivery. Unlike dengue, Zika's sexual transmission made condom use a necessary public health intervention during the 2016 PHEIC.

Question 5

What are the symptoms of Zika?

Accepted Answer

Approximately 80% of Zika infections are asymptomatic. Symptomatic cases cause a mild 2-7 day illness: low-grade fever; rash (typically a fine maculopapular rash starting on the face and trunk); joint and muscle pain; and conjunctivitis. The illness is self-limiting and requires only symptomatic treatment. However, rare complications — Guillain-Barré syndrome (ascending paralysis) in adults, and congenital Zika syndrome in fetuses — are the serious health concerns.

Question 6

Is there a Zika vaccine?

Accepted Answer

No approved Zika vaccine exists. Multiple candidates (mRNA, DNA, virus-like particle, inactivated) reached Phase 1-2 clinical trials after the 2016 PHEIC, but stalled as the outbreak waned and commercial interest reduced. The challenge of demonstrating vaccine efficacy requires large populations during active transmission. Research continues — particularly for protective immunisation of women of reproductive age in endemic regions.

Question 7

How is Zika prevented?

Accepted Answer

Primary prevention: avoiding Aedes aegypti bites — using DEET-containing repellents; wearing long sleeves and trousers; using air conditioning or window/door screens; eliminating standing water breeding sites. Sexual transmission prevention: using condoms for 3 months after potential exposure (men), 2 months (women without pregnancy risk). Pregnant women should avoid travel to areas with active Zika transmission. No vaccine is available.

Question 8

What is Guillain-Barré syndrome in Zika?

Accepted Answer

Guillain-Barré syndrome (GBS) — an immune-mediated neuropathy causing ascending limb weakness — was noted at 15-fold higher rates in French Polynesia and Brazil during Zika outbreaks. GBS from Zika (and from other infections including Campylobacter and influenza) is triggered by molecular mimicry — immune responses cross-reacting with peripheral nerve proteins. Most patients recover, but some require prolonged mechanical ventilation. Management includes IVIg or plasma exchange.

Question 9

How did the 2016 Zika PHEIC shape global health preparedness?

Accepted Answer

The 2016 Zika PHEIC accelerated: novel platform vaccine development (including mRNA vaccines — subsequently critical for COVID-19); rapid diagnostic test development; point-of-care testing for sexual transmission; guidelines for management of pregnancy in arboviral emergencies; and vector control coordination. It also highlighted gaps: the nearly complete absence of Zika in global health preparedness planning before 2015 demonstrated the need for broader arboviral surveillance and platform approaches.

Question 10

What surveillance is needed?

Accepted Answer

Detecting Zika requires: syndromic surveillance for acute undifferentiated febrile illness with rash; laboratory testing of suspected cases (RT-PCR for acute infection, IgM serology); reporting of congenital abnormalities in infants born to potentially exposed mothers; entomological surveillance for Aedes aegypti; and environmental surveillance in new areas. Cross-reactive flavivirus serology (from dengue and yellow fever vaccination) complicates Zika serology.

Question 11

How does GMJ News cover Zika?

Accepted Answer

GMJ News tracks WHO Zika situation reports, congenital Zika syndrome surveillance, arboviral research and vector control developments. Zika is primarily a concern for Georgian travellers and healthcare workers managing imported cases. The broader arboviral context — shared with dengue and yellow fever — is directly relevant as Aedes albopictus expands in the Caucasus region.

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