02 Aug 2016

Zika virus – update and advice for travellers including pregnant women and those planning pregnancy

Advice for travellers has been updated based on epidemiological information Zika virus – update and advice for travellers including pregnant women and those planning pregnancy

This updates and replaces the news item of 10 June 2016.

Specific areas where current active Zika virus (ZIKV) transmission is ongoing are often difficult to determine, and subject to change over time. Areas with active (i.e. locally acquired cases in the last 3 months) or past ZIKV transmission have now been classified into 4 risk categories based on the current and potential epidemiological situation.

The main outbreak region is currently South and Central America, the Caribbean and Oceania (Melanesia, Micronesia and Polynesia only). Certain areas outside the main outbreak region are also reporting ZIKV cases. Public Health England (PHE) has provided an A-Z list of affected areas and information on the four risk categories.

Where Zika transmission has been reported, information and recommendations for travellers is also provided in the ‘other risk’ section of our Country Information pages, and these will continue to be updated as new information becomes available.

Map: Countries or territories with reported confirmed autochthonous (locally acquired) cases of Zika virus infection in the past 3 months
Source: ECDC

  The map above outlines the countries or territories with reported confirmed locally acquired cases of Zika virus infection in the last three months. The European Centre of Disease Prevention and Control (ECDC) provides updated information on current active ZIKV transmission.

In addition, a map of countries or territories that have reported ZIKV transmission in the past nine months has been provided by ECDC to assist healthcare professionals advising returned travellers who are pregnant.

ZIKV is a dengue-like virus that is transmitted by Aedes mosquitoes, most commonly Aedes aegypti. A relatively small number of cases of sexual transmission of ZIKV have also been reported. The infection often occurs without symptoms but can also cause an illness similar to dengue. For those with symptoms, the disease is usually mild and short-lived. Serious complications and deaths from ZIKV are not common. However, based on a growing body of research, there is scientific consensus that ZIKV is a cause of microcephaly and other congenital anomalies, and Guillain-Barré syndrome [1-5]. These complications continue to be investigated, and from hereon, the congenital anomalies (congenital malformations and other nervous system complications, including microcephaly) associated with ZIKV infection will be referred to as Congenital Zika Syndrome (CZS).

In Brazil, as of 23 July 2016, 8,703 suspected cases of fetal/neonatal microcephaly reported since 22 October 2015, 1,749 have been confirmed as microcephaly and/or other abnormalities of the central nervous system, suggestive of congenital Zika virus infection [6]. The majority of confirmed cases of microcephaly occurred in municipalities in the North Eastern region. Other countries, with recent reports of ZIKV activity, have also reported cases of fetal microcephaly and/or abnormalities of the CNS, detected during pregnancy or in new-borns and suggestive of CZS [5-8].

There is now scientific consensus that Zika virus is a cause of Guillain-Barré syndrome. A potential association of ZIKV with Guillain–Barré syndrome (GBS) was first reported in 2014, during an outbreak in French Polynesia [9]. Since the first locally acquired cases of ZIKV were confirmed in north-east Brazil in May 2015, thirteen countries or territories globally have reported increased incidence of GBS and/or laboratory confirmed ZIKV infection in GBS cases [1, 5, 8, 10].

Advice for travellers

Our Country Information pages ‘Other Risk’ section provides information on ZIKV transmission and recommendations for travellers.  

An A-Z list of countries, territories or areas that have reported ZIKV transmission and the risk category is also available from PHE.

There is currently no vaccine available to prevent ZIKV.

Aedes mosquitoes transmit ZIKV (as well as diseases such as chikungunya, dengue and yellow fever). Aedes mosquitoes bite predominantly in the day, particularly during mid-morning and late afternoon to dusk. This type of mosquito is unlikely to be found at altitudes over 2,000m.

You should take insect bite avoidance measures during daytime and night time hours, to reduce the risk of infection with ZIKV and other mosquito borne diseases. A good repellent containing N, N-diethylmetatoluamide (DEET) should be used on exposed skin, together with light cover-up clothing. If sunscreen is needed, repellent should be applied after sunscreen. Sunscreen should be 30 SPF or above to compensate for DEET- induced reduction in SPF. Any additional concerns should be discussed with your healthcare provider.

If you are a UK national who lives in an area with active ZIKV transmission, and you have concerns, you should seek advice from your local healthcare provider who will be able to advise you based on your individual circumstances.

A. Pregnant women and their male partners who are planning to travel

There is now scientific consensus that ZIKV infection during pregnancy is a cause of some birth defects such as abnormalities of the central nervous system, including microcephaly.

i. If you are pregnant:

  • It is recommended that you should postpone non-essential travel to areas with current active ZIKV transmission designated as ‘high risk’ (see A-Z list) until after pregnancy.
  • You should consider postponing non-essential travel to areas with current active ZIKV transmission designated as ‘moderate risk’ (see A-Z list) until after pregnancy.
  • In the event that travel to an area with active ZIKV transmission cannot be postponed, you should make sure you are fully aware of the risks ZIKV may present.
  • In addition, you should be scrupulous with mosquito bite avoidance measures both during daytime and night time hours (but especially during mid-morning and late afternoon to dusk, when the mosquito is most active). Public Health England has produced an information leaflet: mosquito bite avoidance for travellers.
ii. If your female partner is pregnant, condom use is advised during vaginal, anal and oral sex to reduce the risk of transmission during travel and for the duration of the pregnancy even if you did not develop symptoms compatible with ZIKV infection.

B. Pregnant women who have travelled

  • If you are pregnant and you have travelled in an area reporting active ZIKV transmission in the last 9 months (details can be seen on our Country Information pages ‘other risk’ section), you should seek advice from your GP or midwife on your return to the UK, even if you have not been unwell. Your GP or midwife will discuss whether you need further evaluation such as fetal ultrasound scanning, and, if necessary, referral to the local fetal medicine service.
  • If you are currently experiencing symptoms suggestive of ZKV infection, your GP will arrange testing as appropriate.

C. Women planning pregnancy or at risk of getting pregnant and their male partners

  • Before booking travel, women planning pregnancy within 8 weeks following travel should check the Zika risk for their destination (see A – Z list) and consider any travel advisories. You should discuss your travel plans with your healthcare provider to assess your risk of infection with ZIKV and, where travel is unavoidable, receive advice on mosquito bite avoidance measures. See information on factors that health professionals should consider when assessing the risk of infection with ZIKV.
  • You should seek advice from your healthcare provider on the potential risks of ZIKV infection in pregnancy.
  • It is recommended that you avoid becoming pregnant while travelling in an area with active ZIKV transmission, and for 8 weeks after your return home. Following this, attempts to conceive can resume.
  • In addition, you should be scrupulous with mosquito bite avoidance measures both during daytime and night time hours (but especially during mid-morning and late afternoon to dusk, when the mosquito is most active). Public Health England has produced an Information leaflet: mosquito bite avoidance for travellers.
  • If you are planning pregnancy and you develop symptoms compatible with ZIKV infection on your return to the UK, seek advice from your GP; testing will be arranged as appropriate. It is recommended you avoid becoming pregnant for a further 8 weeks following recovery.
  • For women with a male partner who has travelled to an area with active ZIKV transmission, effective contraception is advised to prevent pregnancy AND condom use is advised for your partner  during vaginal, anal and oral sex to reduce the risk of transmission during travel and:
    • for 8 weeks after his return from an active ZIKV transmission area if he has not had any symptoms compatible with ZIKV infection
    • for 6 months following the start of symptoms if a clinical illness compatible with ZIKV infection or laboratory confirmed ZIKV infection was reported.

Following this, attempts to conceive can resume.

This is a precaution and may be revised as more information becomes available.

D. Preventing sexual transmission

A relatively small number of cases of sexual transmission of ZIKV have been reported. The vast majority of cases have involved men who experienced typical ZIKV symptoms at or before the estimated time of sexual transmission to their female partners.

There is only one published report of transmission by a man who had travelled to an area with active ZIKV transmission but never experienced ZIKV symptoms. Transmission of ZIKV from a female to a male sexual partner, and from a male to a male sexual partner has also been reported but these appear to be very rare events.

Zika virus has been shown to be present in semen, although it is not yet known how long this can persist, or whether the duration of virus persistence is longer in men who experience ZIKV symptoms. There has been one report of ZIKV RNA being detected (by PCR) in the female genital tract but it is not yet known how long this can persist.

The overall risk of sexual transmission of ZIKV is considered to be low, but the number of reports is increasing. Zika is usually an asymptomatic or mild illness so sexually transmitted cases of infection may not be recognised.  Individuals who wish to reduce the risk of transmission may consider using condoms during vaginal, anal and oral sex. Condom use is recommended for all travellers whist visiting an area with active ZIKV transmission. Additionally, if the man has clinical illness compatible with Zika virus infection, condom use should commence at the onset of the illness and continue for 6 months. If the man has travelled to an area with active ZIKV transmission but does not experience symptoms, condom use is advised for 8 weeks after leaving the area.

This is an increase from the previously recommended 4 weeks of condom use, consistent with updated guidance from WHO and ECDC, and follows a recent report of asymptomatic sexual transmission that is believed to have occurred between 21 and 36 days after leaving an area with active ZIKV transmission [11]. This is a precaution and may be revised as more information becomes available. Individuals with further concerns regarding potential sexual transmission of ZIKV and options for contraception should contact their GP for advice. Further information is also available from Public Health England.

Advice for health professionals

Our Country Information pages ‘other risk’ section provides information on ZIKV transmission and the specific recommendations for travellers. The A-Z list from PHE and our Outbreak Surveillance section may also be helpful. A comprehensive risk assessment should be undertaken for any traveller going to areas with active ZIKV transmission (locally acquired cases reported in last 3 months). See information on factors that health professionals should consider when assessing the risk of infection with ZIKV.

Health professionals should recommend that:

  • Pregnant travellers postpone non-essential travel to areas with current active ZIKV transmission designated as high risk (see A-Z list) until after pregnancy.
  • Pregnant women should consider postponing non-essential travel to areas with active transmission designated as ‘moderate risk’ (see A-Z list) until after pregnancy.
  • These recommendations can be seen on our Country Information pages.
  • Women should avoid becoming pregnant while travelling in an area with current active ZIKV transmission, and for 8 weeks after leaving an area with active ZIKV transmission.
  • In the event that travel to an area with current active ZIKV transmission cannot be postponed, the pregnant traveller or those planning pregnancy must be informed by the healthcare provider of the risks which ZIKV may present. In addition, the use of scrupulous mosquito bite avoidance measures both during daytime and night time hours (but especially during mid-morning and late afternoon to dusk, when the mosquito is most active) should be emphasised, and an information leaflet provided.
  • Pregnant women who visited an area with active ZIKV transmission while pregnant, or who become pregnant within 8 week  of leaving this country, should contact their GP, obstetrician or midwife for further advice, even if they have not been unwell. Further information about when to perform fetal ultrasound scanning, and, if necessary, referral to the local fetal medicine service is available.
  • Travellers should be advised about potential sexual transmission of ZIKV and the risks ZIKV may pose in pregnancy; specific advice on sexual transmission can be found in the ‘Advice for travellers’ section above.

ZIKV should be considered among the differential diagnoses of patients with fever, or other symptoms suggestive of ZIKV infection, returning from countries with active ZIKV transmission. Further information about diagnosis is available from Public Health England.

If a case of ZIKV infection is suspected, samples need to be sent to PHE’s Rare and Imported Pathogens Laboratory (RIPL); this should be done by liaising with the local diagnostic laboratory. In addition to completing any local laboratory request form, a RIPL request form also needs to be completed by the clinician assessing the patient.

Guidance for health professionals on assessing pregnant women with a history of travel to an area with active ZIKV transmission during pregnancy is available from Public Health England [12].

Guidance for health professionals on ZIKV and immunocompromised patients who wish to travel or who have travelled to ZIKV affected areas is available from Public Health England [13].

Health professionals should also be vigilant for any increase of neurological and autoimmune syndromes (in adults and children), or congenital malformations/birth defects in new born infants (where the cause is not otherwise evident) in patients with a history of travel to areas where with active ZIKV transmission is known to occur [14, 15].

Resources

  1. World Health Organization, Zika situation report. 14 April 2016. [Accessed 2 August 2016]
  2. Martines RB, Bhatnagar J, Keating MK, et al. Notes from the Field: Evidence of Zika Virus Infection in Brain and Placental Tissues from Two Congenitally Infected Newborns and Two Fetal Losses — Brazil, 2015. MMWR Morb Mortal Wkly Rep 2016;65:1–2. [Accessed 2 August 2016]
  3. ?Miranda-Filho, B. Maria Turchi Martelli, C.  Arraes de Alencar Ximenes R. et al. Initial description of the presumed congenital zika syndrome. American Journal of Public Health: April 2016, Vol. 106, No. 4: 598–600 [Accessed 2 August 2016]
  4. Rasmussen SA, Jamieson DJ, Honein MA, Petersen LR. Zika Virus and Birth Defects – Reviewing the Evidence for Causality. NEJM April 16 [on-line]. [Accessed 2 August 2016]
  5. European Centres for Disease Prevention and Control. Rapid Risk Assessment – Zika virus disease epidemic: potential association with microcephaly and Guillain- Barré. Fifth update 11 April 2016 [Accessed 2 August 2016]
  6. Pan American Health Organization and World Health Organization, Regional Zika Epidemiological Update (Americas) July 29, 2016 [Accessed 2 August 2016].
  7. Pan American Health Organization and World Health Organization. Zika Epidemiological Update, 8 April 2016. Washington, D.C.: PAHO/WHO; 2016 [Accessed 2 August 2016]
  8. World Health Organization. Zika virus microcephaly and Guillan Barré syndrome: Situation Report. 7 April 2016. [Accessed 2 August 2016]
  9. European Centre for Disease Control and Prevention. Zika virus outbreak French Polynesia. 14 February 2014. [Accessed 2 August 2016]
  10. Public Health England. Zika virus and Guillain-Barré syndrome. 22 April 2016 [Accessed 2 August 2016]
  11. Fréour, T. Mirallié, S., Hubert, B. et al Sexual Transmission of Zika virus in an entirely asymptomatic couple returning from the Zika epidemic area, France, April 2016. Eurosurveillance, Volume 21, Issue 23, 09 June 2016. [Accessed 2 August 2016].
  12. Public Health England. Zika virus: interim algorithm for assessing pregnant women with a history of travel during pregnancy to areas with active Zika virus (ZIKV) transmission. 26 April 2016. [Accessed 2 August 2016]
  13. Public Health England. Zika virus and immunocompromised patients. 27 July 2016. [Accessed 2 August 2016]
  14. Public Health England. Guidance: Zika virus congenital infection: algorithm and interim guidance for neonatologists and paediatricians. 24 March 2016 [Accessed 2 August 2016]
  15. Royal College of Obstetricians and Gynaecologists: Public Health England briefing on the Zika virus and vector borne diseases for returning travellers [Accessed 2 August 2016]

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