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Travel health information for people travelling abroad from the UK

Zika Virus Infection

Introduction

Zika virus (ZIKV) was first identifed in April 1947, when fever developed in a research rhesus monkey in the Zika Forest of Uganda.

The first well-documented report of human ZIKV infection occurred in 1964, and since then occasional cases in humans have been reported in numerous countries in Africa and Asia.

In 2007, the first ever outbreak of ZIKV occurred on Yap Island in the Federated States of Micronesia. This was also the first time that ZIKV was reported out with Africa and Asia. In October 2013, a large outbreak occurred in French Polynesia, followed by other outbreaks in the Pacific islands of New Caledonia, Cook Islands and Easter Island.

In 2015, cases of ZIKV were reported in several Caribbean Islands and Brazil, progressing to an outbreak that spread to the Americas. The outbreak has continued to evolve in 2016, with ZIKV reported in an increasing number of countries.

Country/territory/area are assigned into categories of risk of ZIKV transmission.  The outbreak of ZIKV is evolving; the risk of transmission in a country/territory/area as the outbreak progresses and these categories are regularly updated:

  • Country/territory/area with a High Risk of ZIKV transmission
  • Country/territory/area with a Moderate Risk of ZIKV transmission
  • Country/territory/area with a Low Risk of ZIKV transmission
  • Country/territory/area with a Very Low Risk of ZIKV transmission

Of particular concern is the link between ZIKV infection in pregnancy, and the increase in number of birth defects being recorded in Brazil, notably babies being born with microcephaly (smaller than normal head).

There is also an association between ZIKV outbreaks and the occurrence of Guillain-Barré syndrome (GBS), a serious condition of the nervous system. The risk of developing GBS following ZIKV infection is currently unknown, but thought to be very low.

Transmission

ZIKV is spread by the Aedes species of mosquito including the Aedes aegypti mosquito which predominantly bites during the day.

There have been some reports of ZIKV being transmitted sexually. ZIKV has been found in semen two months after illness and in the female genital tract.  

The Illness

Most people infected with ZIKV will have only very mild, or no symptoms. Symptoms usually start 2-12 days after the bite of an infected mosquito and last for 4-7 days. They include: rash, itch, mild fever, headache, red eyes, muscle and joint pains. Other less common symptoms include: loss of appetite, diarrhoea, constipation, abdominal pain and dizziness.

Treatment

There is no specific treatment for ZIKV infection available. Most people will get better without any treatment. Symptoms like headache and fever can be treated symptomatically. Hospital care is indicated in severe illnesses or if complications arise.

Recommendations for Travellers

There is no medicine or vaccine available that prevents ZIKV infection.

Travellers are advised to seek travel advice from a health care provider at least 6-8 weeks in advance of travel, but particularly important if you are pregnant or planning pregnancy.

All travellers to countries with ZIKV transmission must consider:

Mosquito Bite Avoidance

Strict Bite avoidance measures are recommended for all travellers, especially pregnant women.  Aedes sp mosquitoes are particularly persistent and aggressive biters.

  • 50% DEET- based insect repellents should be applied regularly (according to manufacturers instructions).
    • DEET is appropriate for use in pregnancy.
    • If DEET is unsuitable then another, proven alternative should be used.
    • Wearing loose, cover-up clothing is recommended.
      • Clothing can be impregnated or sprayed with the insecticide permethrin.
      • Insecticide-impregnated bed nets and air conditioning should be used in bedrooms.
      • Reduction of mosquito breeding sites around hotel rooms/homes is advised for longer-term stays.

Travel Insurance

Travellers should be strongly advised not to travel without adequate insurance.

  • Pregnant women should check with their travel insurance company that they are covered under the policy before booking their trip. 

The outbreak of ZIKV is evolving, pregnant women should be aware that the risk of ZIKV in any country may change during the time between planning the trip and travelling.

Additional Travel Recommendations

These are based on the transmission risk of ZIKV in a country/territory/area.

High risk or Moderate risk of ZIKV transmission

Pregnant Women

Until the link between ZIKV and adverse pregnancy outcomes has been fully clarified pregnant women should:

Pregnant women should discuss the risk of ZIKV with their travel healthcare provider so they can make a fully informed decision regarding travel. Pregnant women should:

  • Remember that malaria and other travel related hazards may pose a risk during pregnancy
    • Use condoms to prevent sexual transmission of ZIKV during travel and throughout the pregnancy.
    • On return, seek early obstetric review, even if well.

Women of child bearing age

Use contraception and condoms during travel and for 8 weeks afterwards to avoid the risk of ZIKV in an unplanned pregnancy and sexual transmission of ZIKV.

Men

Use condoms during travel to avoid the risk of sexual transmission of ZIKV, particularly during conception or pregnancy and for:

  • 8 weeks after travel if asymptomatic and partner(s) are not pregnant.
  • 6 months after travel if symptomatic and partner(s) are not pregnant.
  • The duration of partner(s) pregnancy.

Low risk of ZIKV transmission

Women who are pregnant and women planning pregnancy

In Low Risk areas the risk of ZIKV transmission during travel is low.  Pregnant women and women planning pregnancy should discuss the risk of ZIKV infection and its association with adverse pregnancy outcomes with their travel health provider before deciding whether to continue with travel plans.

Travellers who develop illness during travel should seek medical attention at their destination. Those who are diagnosed with ZIKV should:

  • Pregnant woman - use condoms for 8 weeks to prevent sexual transmission of ZIKV and seek early obstetric review on return.
  • Non pregnant women should use contraception and condoms during travel and for 8 weeks afterwards to avoid the risk of ZIKV in an unplanned pregnancy and sexual transmission of ZIKV.
  • Men should use condoms during travel and for 6 months after travel to avoid the risk of sexual transmission of ZIKV, particularly during conception or pregnancy. 
  • Men with pregnant partner(s) should use condoms for the duration of the pregnancy.

Very Low risk of ZIKV transmission

For travellers to a Very Low risk country/territory/area there are no additional measures required to prevent ZIKV infection.

Travellers who develop illness during travel should seek medical attention at their destination. Those who are diagnosed with ZIKV should:

  • Pregnant woman - use condoms for 8 weeks to prevent sexual transmission of ZIKV and seek early obstetric review on return.
  • Non pregnant women should use contraception and condoms during travel and for 8 weeks afterwards to avoid the risk of ZIKV in an unplanned pregnancy and sexual transmission of ZIKV.
  • Men should use condoms during travel and for 6 months after travel to avoid the risk of sexual transmission of ZIKV, particularly during conception or pregnancy. 
  • Men with pregnant partner(s) should use condoms for the duration of the pregnancy

On Return

Medical attention must be sought quickly for any feverish illness experienced whilst travelling or on return home. Remember that other travel related hazards, including malaria, may be present in ZIKV affected countries, and can be serious, particularly if you are pregnant.

Contraception and guidelines for reducing sexual transmission should be followed as detailed above.

Travellers returning from countries affected by ZIKV cannot donate blood for 4 weeks after return if they have had no symptoms, or 6 months if they have had symptoms of ZIKV infection. Scottish National Blood Transfusion Service (SNBTS) have a policy of 28 day deferral for donors who have visited Zika affected countries, and also for sexual partners of anyone who has been diagnosed with ZIKV infection (in the six months before sexual contact). This is in common with other UK blood services. This is a precautionary measure to protect the blood supply, particularly in relation to pregnant women.

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