Zika Virus Disease
Also known as Zika fever
This article is general health information for the selected condition. It is not a diagnosis and does not replace clinical judgement. If you have questions or need treatment advice, please consult a qualified healthcare professional.
What is zika virus disease?
Zika virus is spread mainly by Aedes mosquitoes and usually causes a mild illness or none at all. Its importance lies almost entirely in pregnancy, because infection can cross the placenta and cause microcephaly and other severe brain abnormalities in the developing baby. It can also be transmitted sexually.
Causes
- Zika virus, a flavivirus
- Bite of an infected Aedes mosquito
- Sexual transmission from an infected partner
- Mother to fetus transmission during pregnancy
- Rarely blood transfusion
Symptoms
- No symptoms in around 80 percent of infections
- Mild fever
- Itchy maculopapular rash
- Conjunctivitis with red eyes
- Joint and muscle pain
- Headache
- Symptoms usually lasting two to seven days
Risk factors
- Travel to or residence in areas with transmission
- Pregnancy or planning pregnancy
- Unprotected sex with a partner who has travelled to an affected area
- Outdoor daytime exposure, when Aedes mosquitoes bite
Diagnosis
- PCR testing of blood or urine in the first weeks
- Serology, with cross reactivity against dengue complicating interpretation
- Detailed fetal ultrasound in pregnancy
- Amniocentesis in selected cases
- Exclusion of dengue and chikungunya
Treatment
- No specific antiviral treatment
- Rest, fluids and paracetamol for symptoms
- Avoiding aspirin and NSAIDs until dengue is excluded
- Specialist fetal medicine follow up in pregnancy
- Mosquito bite prevention
- Condom use or abstinence for a defined period after travel
Self care
- Rest and drink plenty of fluids
- Use paracetamol rather than aspirin or anti inflammatories until dengue is excluded
- Prevent further mosquito bites to reduce onward spread
- Use condoms after travel to an affected area
- Attend all antenatal scans if pregnant
When to see a doctor
Book an appointment if:
- Fever and rash after travel to an affected area
- Pregnancy with possible Zika exposure
- Planning pregnancy after travel to an affected region
- A partner who has travelled to an affected area
- New weakness or tingling after a viral illness
- Joint pain persisting after recovery
Some symptoms need emergency care rather than an appointment. See the warning signs listed above.
Prevention
- Avoid travel to affected areas during pregnancy
- Use insect repellent and cover up during daylight hours
- Use condoms or abstain for the recommended period after travel
- Delay conception for around two months for women and three for men after exposure
- Remove standing water around accommodation
Outlook
Zika is mild or asymptomatic for most people and resolves within a week. The serious concern is congenital infection, which can cause microcephaly and lasting neurological damage in the baby. Guillain Barre syndrome is a rare complication. For non pregnant adults the outlook is excellent.
Common questions
Why is Zika so serious in pregnancy?
The virus can cross the placenta and damage the developing brain, causing microcephaly, eye abnormalities and other congenital problems. Risk is present throughout pregnancy and is highest in the first trimester.
How long should conception be delayed after travel?
Guidance varies, but a common recommendation is that women wait about two months and men about three months after returning from an affected area, since the virus persists longer in semen.
Can it be passed through sex?
Yes. Zika is one of the few mosquito borne viruses with documented sexual transmission, which is why barrier protection is advised after travel even if the traveller had no symptoms.
References
Important: Dard AI is not a medical device and does not diagnose, treat, or replace clinician judgement. This article is general information only. Always consult a qualified healthcare professional about diagnosis and treatment, and seek emergency care for severe or rapidly worsening symptoms.