Zika epidemic in the Americas and Caribbean continues to evolve: updated ECDC rapid risk assessment

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​The Zika epidemic in the Americas and Caribbean continues to evolve and expand geographically. Despite growing evidence of a link, uncertainties persist about the frequency and the clinical spectrum of mother-foetus Zika virus infections, the association between Zika virus and Guillain–Barré syndrome, and Zika virus and other neurological complications, concludes ECDC’s updated rapid risk assessment.

The Zika epidemic in the Americas and Caribbean continues to evolve and expand geographically. Despite growing evidence of a link, uncertainties persist about the frequency and the clinical spectrum of mother-foetus Zika virus infections, the association between Zika virus and Guillain–Barré syndrome, and Zika virus and other neurological complications, concludes ECDC’s updated rapid risk assessment.  

Zika virus and pregnancy

Pregnant women and women who are planning to become pregnant constitute a risk group with regard to Zika virus infection. It is likely that the risks of infection of the foetus as well as the risk of developing congenital central nervous system malformations depends on at what point in the pregnancy the mother is infected with Zika virus. It is also plausible that other risk factors, such as the mother’s age and nutritional status, influence the risk of transplacental transmission as well, but there are currently no data available to assess such risk factors. 
 
To estimate the risk that a foetus becomes infected when a pregnant woman is infected requires prospective cohort studies of pregnant women in areas with high transmission. Such studies are ongoing in several countries in South America but results will not come until the infected mothers have given birth.  
 

Zika virus and Guillain–Barré syndrome

Cases of Guillain–Barré continue to be reported from the Zika affected countries but no new scientific evidence regarding the association has been published since the last ECDC rapid risk assessment.  
 

Risk of transmission in continental EU

Aedes albopictus is the only mosquito species established in continental EU that potentially could transmit Zika virus. However, the competence of European Aedes albopictus populations to transmit the virus has not been confirmed.  
 

The risk of transmission of Zika virus infection is extremely low in the EU during the winter season as temperatures are unsuitable for Aedes albopictus activity. During the summer, local transmission in the EU following the introduction of the virus by an infected traveller is a possibility around the Mediterranean coast where the Aedes albopictus species is well established.

In order to reduce the risk of local transmission in EU Member States, EU Overseas Countries and Territories, and EU Outermost Regions, the early detection of imported cases of Zika virus infection, in particular where vectors are present, is important.

EU/EEA Member States are recommended to consider the mitigation measures, such as advising travellers visiting these countries to take measures to prevent mosquito bites, as well as recommending that pregnant women and women planning to get pregnant to consider postponing non-essential travel to affected areas until after delivery.

The rapid risk assessment also includes options on risk mitigation concerning substances of human origin, surveillance and preparedness.

Read the risk assessment:

Rapid Risk Assessment: Zika virus disease epidemic: potential association with microcephaly and Guillain–Barré syndrome, third update

Read more:Zika epidemic in the Americas and CaribbeanCountries and territories with local Zika transmission