Zika virus (ZIKV) is a flavivirus first identified in Uganda in 1947. It causes relatively mild disease and is transmitted by mosquitoes of the genus Aedes. In 2007, an outbreak on Yap Island in the Federated States of Micronesia was the first time ZIKV transmission had occurred outside Africa and Asia. In 2013, a further outbreak was reported in French Polynesia. This outbreak continued into 2014 and it was in this outbreak that the first cases of possible perinatal transmission and Gullain-Barré syndrome were reported. In 2014 and 2015, further outbreaks in the Pacific Islands were reported.
In 2015 to 2016, ZIKV spread throughout South and Central America, the Caribbean and parts of North America. The spread of ZIKV into South America coincided with an increase in microcephaly, a condition where the head cirumference is smaller than normal, as well as developmental defects in newborn children. This led to a Public Health Emergency of International Concern (PHEIC) being declared by the World Health Organisation (WHO) between February and November 2016. The PHEIC has now been replaced by the WHO's longer term Zika Strategic Response Plan.
Since 2016, ZIKV infection in pregnancy has been established as the cause of Congenital Zika syndrome, and this may have severe and fatal consequences for the fetus. Sexual transmission of ZIKV is rare but has been documented.
Published 29 January 2016
Previous update 9 July 2018
Last updated 27 February 2019
The risk to Scotland is considered very low due to the absence of the Aedes mosquito and the low risk of sexual transmission associated with imported cases.
For travellers to affected countries there is a low risk of infection which may result in mild symptoms in the majority of cases.
For pregnant travellers or women who may become pregnant during or soon after travel, the risk is considered higher due to Congenital Zika Syndrome.
There is a low risk of sexual transmission of ZIKV.
Our recommendations for travellers to countries where ZIKV is circulating
The risk of ZIKV transmission in any country or area is determined by Public Health England (PHE) and can be viewed on the PHE website.
Travellers should seek travel advice from a healthcare provider at least six to eight weeks in advance of travel, this is particularly important if pregnant or planning pregnancy.
Advice for the travelling public can be found on our fitfortravel website.
Specific advice on Zika virus prevention and management and county-by country advice for health professionals advising travellers can be found on our TRAVAX website.
Travellers who develop illness during travel should seek medical attention at their destination.
Those diagnosed with ZIKV when travelling
Pregnant women who are diagnosed with ZIKV should use condoms during travel and for eight weeks afterwards to reduce the risk of sexual transmission and seek early obstetric review.
Diagnosis and reporting
Clinicians are advised to consider the possibility of ZIKV in patients presenting with a febrile illness on return from countries with a risk of ZIKV or whose sexual partner has returned from these countries, in the last two months if it's a female partner or three months if it's a male partner. This is particularly important for women of childbearing age who are, or may be pregnant.
Any requests for testing have to be directed to PHE's Rare and imported pathogens laboratory (RIPL).
Testing should only be undertaken in those with current or a history of, symptoms. Clinicians ordering tests for patients with a relevant travel history should be explicit in requesting ZIKV testing and should indicate the country and region of travel on the RIPL request form P1 and whether pregnant, partner pregnant and gestation. Clinicians should send samples to the local laboratory who will carry out appropriate procedures and forward samples. Sample testing advice can be found on the PHE website.
Clinicians should liaise with obstetric colleagues to raise awareness and ensure appropriate investigations and counselling are in place for pregnant patients with a relevant travel history. Negative serology taken four weeks after the last possible exposure to ZIKV, excludes infection. Negative antibody results indicate they do not require extra fetal ultrasound follow-up, unless there are additional concerns. This is arranged through obstetric services.
If help is required with the risk assessment and diagnosis of ZIKV in an individual in Scotland advice should be sought from the local infectious disease consultant.
Reporting of ZIKV in Scotland is through our organisation. For the rest of the UK this is directly through PHE.
Public health implications
Until further evidence is available, a precautionary approach to the risk posed by ZIKV, in particular during pregnancy, is being adopted by public health authorities worldwide.
ZIKV has been detected in semen some months after symptoms of ZIKV, and for some weeks in the female genital tract. A small, but growing number, of sexually transmitted cases of ZIKV infection have been reported worldwide.
In terms of vector control – mosquito control – in flights from affected countries, the International Health Regulations Emergency Committee on ZIKV has advised that standard WHO recommendations should be implemented in order to control Aedes sp mosquitoes.
Further advice for clinicians
Updates on countries
An updated list of countries with risk of ZIKV transmission is available on the PHE website.
Country-by-country advice for health professionals advising travellers can be found on our TRAVAX website.
Clinical pre-travel and post-travel scenario based frequently asked questions are also on our TRAVAX website.
Read the guidance for healthcare professionals on Zika virus infection in pregnancy, developed by the Royal College of Obstetricians and Gynaecologists (RCOG), Royal College of Midwives (RCM), PHE and ourselves:
Other guidelines and publications
Read other guidelines and publications on Zika, below:
- Zika virus information including rapid risk assessments on the European Centre for Disease Prevention and Control (ECDC) website.
- Zika virus weekly situation reports, February 2016 to March 2017 on the WHO website.
- Zika Open is a platform for the fast-track publication of new research on ZIKV and can also be found on the WHO website.
- Alongside PHE, we've produced a leaflet on mosquito bite avoidance for travellers, updated in August 2017.
- PHE algorithm and interim guidance for neonatologists and paediatricians for management of confirmed and potentially infected infants born to parents who travelled to areas with active Zika virus transmission, updated in February 2019, is also available on the PHE website.
- PHE, the Royal College of Nursing (RCN), the RCM and the RCOG have published a leaflet on health advice for pregnant women returning from areas with active Zika virus transmission, updated in February 2019, and available on the PHE website.
- WHO guidelines for the prevention of sexual transmission of Zika Virus: executive summary 2019, available on the WHO website.