[Durgical](https://durgical.com/en/) › [DurgiPedia](https://durgical.com/en/durgipedia/) › [Microbiology](https://durgical.com/en/microbiology/) › [RNA arboviruses](https://durgical.com/en/microbiology/groups/rna-arboviruses/) › Zika virus

[Microbiology](https://durgical.com/en/microbiology/) · [RNA arboviruses](https://durgical.com/en/microbiology/groups/rna-arboviruses/)

# Zika virus

- Virus
- Enveloped
- Exam priority: high

A virus spread by Aedes mosquitoes, and also sexually and from mother to fetus. It is usually mild, but in pregnancy it can cause microcephaly.

Updated 2026-11-01

Also called: ZIKV

## Key points

- Flavivirus spread by Aedes, sexually and vertically
- Congenital syndrome: severe microcephaly, subcortical calcifications, eye lesions, arthrogryposis
- Linked to Guillain–Barré syndrome in adults
- IgM cross-reacts with dengue: PCR is more specific in the acute phase

## At a glance

**Shape**
Spherical, icosahedral capsid

**Genome**
Single-stranded, positive-sense RNA

**Envelope**
Enveloped

**Family**
Flaviviridae, genus Orthoflavivirus

**Size**
About 50 nm

## Morphology

- Enveloped virus with surface protein E, structurally close to dengue virus
- A single serotype

## Transmission

- Bite of Aedes aegypti (main) and Aedes albopictus
- Vertical: mother to fetus during pregnancy
- Sexual
- Blood transfusion; possibly organ transplant

**Reservoir:** Humans in the urban cycle; Non-human primates in the African sylvatic cycle

**Vector:** Aedes aegypti, Aedes albopictus

### Isolation precautions

What the care team adds to standard precautions.

- Standard

## Virulence factors

- Tropism for fetal neural progenitor cells: it halts their growth and kills them, so the brain grows less
- Crosses the placenta and can persist in semen for weeks
- The post-infectious immune response can attack peripheral nerves (Guillain–Barré)

## Diseases it causes

- Zika: mild fever, itchy rash and non-purulent conjunctivitis [Zika virus infection →](https://durgical.com/en/conditions/zika-virus-infection/)
- Congenital Zika syndrome: microcephaly, brain calcifications, eye lesions, contractures and hearing loss
- Guillain–Barré syndrome and other neurological complications [Guillain-Barré syndrome →](https://durgical.com/en/conditions/guillain-barre-syndrome/)

## Clinical picture

- About half or more of infections are asymptomatic
- Itchy maculopapular rash, low fever, non-purulent conjunctivitis, mild arthralgia
- Birth defects can occur even when the mother had no symptoms
- In pregnancy it is also linked to fetal loss, stillbirth and preterm birth

## Diagnosis

- RT-PCR on blood or urine in the acute phase
- Serum IgM, which cross-reacts with dengue and may need neutralization tests
- Serial obstetric ultrasound for microcephaly and calcifications in exposed pregnancies

## Treatment

There is no specific antiviral: rest, fluids and paracetamol for fever and pain. NSAIDs are avoided until dengue is ruled out. Exposed newborns are followed for neurodevelopment, vision and hearing.

Drug class only; doses and regimens are set by the clinician from the current guideline.

## Prevention

- Control of Aedes breeding sites and bite protection, especially in pregnancy
- Condoms or abstinence during pregnancy if the partner was in an area with transmission
- No vaccine is available

## In Colombia

Colombia had a large Zika epidemic in 2015 and 2016, with a rise in microcephaly and Guillain–Barré syndrome; the INS monitors Zika and related birth defects through SIVIGILA.

## Memory aid

Zika "zaps the builders": it switches off the fetal cells that build the brain, so the head stays small.

## Test yourself

Think of the answer, then tap the question to see it.

## Which routes of spread set Zika apart from other arboviruses?

Besides the Aedes mosquito, it spreads sexually and from mother to fetus during pregnancy.

## What are the main findings of congenital Zika syndrome?

Microcephaly, brain calcifications, eye lesions, joint contractures (arthrogryposis), high muscle tone and hearing loss.

## Which adult neurological complication is linked to Zika?

Guillain–Barré syndrome, an acute post-infectious inflammatory polyradiculoneuropathy.

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## Related

- [Dengue virus](https://durgical.com/en/microbiology/dengue-virus/)
- [Chikungunya virus](https://durgical.com/en/microbiology/chikungunya-virus/)

## Related conditions

- [Zika virus infection](https://durgical.com/en/conditions/zika-virus-infection/)
- [Guillain-Barré syndrome](https://durgical.com/en/conditions/guillain-barre-syndrome/)

## What the colours mean

**Gram-positive**
Thick peptidoglycan wall: stains purple.

**Gram-negative**
Thin wall with an outer membrane: stains pink.

**Acid-fast**
Lipid-rich wall (mycobacteria): Ziehl–Neelsen stain.

[← Back to the group: RNA arboviruses](https://durgical.com/en/microbiology/groups/rna-arboviruses/)

Educational content on microorganisms; not a treatment guide and no substitute for a health professional's advice. No doses are given.

Sources: [Zika virus](https://www.who.int/news-room/fact-sheets/detail/zika-virus) (World Health Organization (WHO), 2025); [Appendix A: Type and Duration of Precautions Recommended for Selected Infections and Conditions](https://www.cdc.gov/infection-control/hcp/isolation-precautions/appendix-a-type-duration.html) (CDC, 2024).

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Representative model, for educational purposes only.

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Source: https://durgical.com/en/microbiology/zika-virus/
License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Cite as: DurgiPedia (durgical.com), https://durgical.com/en/microbiology/zika-virus/