Rapid risk assessment: Zika virus disease epidemic: potential association with microcephaly and Guillain–Barré syndrome - 6th update, 23 May 2016
This sixth update assesses the risks associated with the Zika virus epidemic currently affecting countries in the Americas, taking account the latest information available. It provides updated information for travellers to affected countries and EU citizens residing in areas with active transmission. It also assesses the association between Zika virus infection and congenital central nervous system malformations, including microcephaly, as well as the association between Zika virus infection and Guillain–Barré syndrome.
The risk assessment synthesises the main scientific developments from the past month, considers the main risks for the EU and its citizens and sets out a range of options for EU/EEA Member States’ consideration.
The evidence of an association between Zika virus infection during pregnancy and congenital central nervous system malformations, the association between Zika virus infection and Guillain–Barré syndrome and the geographic expansion of the outbreak, mean that the epidemic remains of public health importance.
The evolution of the Zika epidemic in the Americas demands close monitoring as it has a direct impact on the risk of importation and possible occurrence of local transmission in the European Union.
Mosquito-borne transmission risk
Mosquito-borne transmission of Zika virus infection in the EU is only considered possible in areas where mosquitoes capable of carrying and transmitting the virus are present. The transmission depends on several factors related to the mosquito, the virus and the environment, notably:
- The introduction of the virus by a viraemic traveller during the summer season where Aedes albopictus is established can be expected. Aedes albopictus is established around the Mediterranean basin (see ECDC mosquito maps)
- Those areas with Aedes albopictus will have increasingly suitable conditions during the spring (April to June), and by analogy with other mosquito-borne disease transmission, the conditions will remain favourable in those areas during the summer and autumn.
Given the low vector competence of the studied European populations of Aedes albopictus, the likelihood of local vector-borne transmission in the EU is considered to be low to moderate.
In addition, Madeira is of particular concern because of the presence of Aedes aegypti, the primary vector for Zika virus, and the probability of transmission of vector-borne pathogens is considered high during the summer months.
Sexual transmission of Zika virus
There have been confirmed cases of sexual transmission of Zika virus infection from symptomatic male partners throughout 2016, and one instance of transmission from an asymptomatic male.
Scientific studies have shown that the Zika virus can be present in semen up to 62 days after the first symptoms. However, of known cases of sexual transmission, the longest time between the onset of symptoms and transmission is 19 days.
Therefore, to reduce the risk of Zika transmission, males who have been in areas with active transmission should be advised to use a condom for at least one month after returning and use a condom with a pregnant partner until the end of the pregnancy.
Updated country categorisation
ECDC has modified how countries and territories currently experiencing local Zika virus transmission are categorised.
As of week 17, 2016, ECDC extended the period for classifying whether a country or territory has active local transmission from two to three months. This change reflects that Zika virus outbreaks usually last more than two months. In addition, ECDC added a ‘countries and territories with past vector-borne transmission’ category for countries having experienced transmission since 2007 up to three months ago.
Rapid risk assessment: Zika virus disease in Var department, France
16 Oct 2019 - On 1 October 2019, a case of locally acquired Zika virus (ZIKV) disease in France (Hyères city, Var department) was laboratory confirmed. To date, and based on ECDC’s epidemiological assessment, the probability of ongoing vector-borne local transmission in Hyères (and surrounding areas) is considered very low because current evidence does not indicate the existence of a more extensive cluster of ZIKV cases.
Zika virus transmission worldwide
11 Apr 2019 - Since the epidemic in the Americas peaked in the early spring of 2016, a continuous decline in the number of reported Zika virus disease cases has been observed in the majority of countries throughout the Americas and the Caribbean.
Rapid risk assessment: Zika virus disease epidemic. 10th update, 4 April 2017
5 Apr 2017 - This is an updated assessment of the risks associated with the Zika virus epidemic in affected countries, EU Overseas Countries and Territories, and Outermost Regions and in EU Member States within continental Europe.