Zika virus is primarily spread through the bite of the Aedes genus of mosquito that is largely tropical and subtropical in distribution. It has also been recognised that Zika virus infection can be transmitted sexually. HPSC maintain an updated list of countries reporting local transmission of confirmed Zika virus infection.


Latest WHO international situation report

• Since 1 February 2016, Zika virus infection and the related clusters of microcephaly cases and other neurological disorders constitute a public health emergency of international concern (PHEIC). Since 2015, and as of 20 July 2016, WHO has reported 62 countries and territories with mosquito-borne transmission.
• 11 countries have reported evidence of person-to-person transmission of Zika virus, probably via a sexual route.
• On 13 July 2016, the US CDC released a risk assessment for Zika virus spread related to travel to the 2016 Rio Olympics. The assessment concluded that international spread of Zika related to the Games would not significantly alter spread, but that four countries were at special risk, because residents of those countries did not have substantial travel to Zika affected countries, outside of potential exposure at the Olympics: Eritrea, Djibouti, Chad, and Yemen.
• On 15 July 2016, the first suspected female-to-male sexual transmission of Zika virus was reported by the US CDC.
• On 21 July, the media reported that the first Zika vaccine has been approved by Health Canada and the US Food and Drug Administration to begin Phase I clinical trials in humans.

 Travel advice

• Pregnant women are advised to postpone non-essential travel to a Zika affected areauntil after delivery.
• If travel is unavoidable pregnant travellers or those planning pregnancy must be informed by the healthcare provider of the risks which Zika may present.
• It is strongly recommended that women should avoid becoming pregnant while travelling in an area with active Zika virus transmission
• Pregnant travellers or those planning pregnancy who travel to affected areas, should use condoms during vaginal, anal and oral sex for the duration of their stay
• All travellers should follow the advice in the section on Preventing Potential Sexual Transmission.
• All travellers should ensure scrupulous mosquito bite avoidance measures, both during daytime and night time hours but especially during mid-morning and late afternoon to dusk, when Aedes mosquitoes are most active.
• Repellents containing 50% DEET can be used by pregnant women, but higher concentrations should not be used. DEET should be applied after the sunscreen. Sunscreen with a 30 to 50 SPF rating should be applied to compensate for DEET-induced reduction in SPF. The use of DEET is not recommended for infants less than two months of age.

Zika virus can be passed between sexual partners during vaginal, anal, oral sex and possibly during the sharing of sex toys. This is more likely if the man had symptoms of Zika virus infection. For this reason, it is important to practice safe sex (by wearing a condom) with a partner who has recently returned from, or is living in, an affected area.

For females it is also important to prevent sexual transmission of Zika by:

• Using condoms during vaginal, anal and oral sex for the duration of their stay in an affected area.
• Using condoms during vaginal, anal and oral sex for the duration of their pregnancy with a male partner who travelled to an affected area.
• By delaying pregnancy for 8 weeks after return to Ireland.
• If symptomatic with Zika, by delaying pregnancy for 8 weeks after onset of symptoms.

If the male partner travelled to an affected area, prevention of sexual transmission by using condoms during vaginal, anal and oral sex and delaying pregnancy as follows:

• Couples whose male partner was ill with Zika should delay pregnancy for 6 months.
• Couples whose male partner travelled to an affected area but was not ill with Zika should delay pregnancy for 8 weeks. 
• Couples whose male partner travelled to an affected area should use condoms for oral, anal and vaginal sex for the duration of pregnancy.

This precautionary approach is being adopted to minimise the threat to the unborn baby while also minimising inconvenience for the couple.

The HPSC website also provides the following Zika virus resources:

• Frequently asked questions for the general public
• Frequently asked questions for pregnant women and women who are planning a pregnancy
• Clinical guidelines for health professionals on Zika virus infection and pregnancy
• Guidelines for the laboratory investigation of Zika virus infection