Zika virus infection is spread by day-biting mosquitoes. A small number of Zika virus cases have also been reported as spread by sexual contact. Zika virus is a flavivirus (similar to dengue) and was first discovered in a monkey in the Zika forest, Uganda in 1947. It is found in parts of Africa, Asia, the Pacific Islands, Central and South America and the Caribbean.
All travellers to areas where Zika virus is known to occur are at risk of infection, although determining the actual level of risk is difficult. Travellers who spend long periods in areas where Zika virus is common are at increased risk. However, even short-term visitors may be exposed to the virus.
Most people infected with Zika virus have no symptoms. For those with symptoms, Zika virus infection is usually a mild and short-lived illness; severe disease is uncommon. Symptoms may include: fever, headache, conjunctivitis (red, sore eyes), joint and muscle pain, a rash, itching and swollen joints. There is no specific treatment; but rest, fluids and pain relief help relieve symptoms.
Serious complications and deaths from Zika virus are not common. However, Zika virus is a cause of birth defects known as Congenital Zika Syndrome (microcephaly and other congenital anomalies) and neurological problems such as Guillain-Barré syndrome.
Prevention
Travellers should be made aware of the risk of Zika virus in all the destinations they plan to visit. Information about Zika virus transmission in affected countries or territories can be found in the 'Outbreaks' and 'Other Risks' section of our Country Information pages. Further information including maps showing the current risk categories can be found in the factsheet: Zika virus: Evaluating the risk to individual travellers. Always check the Country Information page for the most up to date information. Zika virus surveillance systems vary from country to country, so Zika virus cases may not always be diagnosed or consistently reported in some countries.
There is no vaccine or medication to prevent Zika virus infection. Prevention is by minimising mosquito bites; the mosquito that spreads Zika virus is most active in daylight hours. All travellers should be vigilant with insect bite precautions. See also preventing infection by sexual transmission.
Travlellers to regions where Zika virus occurs should ideally seek travel health advice from their GP, practice nurse or a travel clinic at least 4-6 weeks before travel. This is particularly important for those who are pregnant, planning to become pregnant, anyone with a severe, chronic medical condition or a medical condition that weakens their immune system (immunosuppression).
Occasionally, if there is a large outbreak of Zika virus in a destination, with an associated high risk of Zika virus exposure, this will be highlighted by NaTHNaC and pregnant women should consider postponing non-essential travel until after the pregnancy. In other destinations, pregnant women should discuss the suitability of travel and the potential risk that Zika virus may present with their health care provider. Recommendations for affected countries are found in the 'Other Risks' section of the individual country pages.
UK Health Security Agency provide health advice for women returning form a country or area with risk for Zika virus transmission.