Zika virus: risk of importation increases, but risk of spread in Europe remains extremely low during winter

Outbreak in the Americas

Since May 2015, Zika virus disease – an emerging viral disease transmitted by Aedes mosquito bites – has spread in the Americas and the Caribbean, following the reporting of the first cases in Brazil. The arrival of the virus has been associated with steep increases in babies born with abnormally small heads and in cases of Guillain-Barré syndrome. A causal relationship between Zika virus infection and birth defects and neurological syndromes has not been established, but is strongly suspected.

Risk of importation and spread in Europe 

As Zika virus disease continues to spread in the WHO Region of the Americas, the risk of Zika-infected travellers entering Europe increases. Imported cases have been reported in several European countries.

During the winter, the risk of Zika virus transmission in Europe is extremely low. While Aedes mosquitoes – the same mosquitoes that spread dengue and chikungunya – are present in several European countries, especially in the Mediterranean area, the current climatic conditions are not suitable for their activity. 

With the onset of spring and summer, the risk of Zika virus disease transmission in Europe will increase, as mosquitoes find better breeding grounds in warmer climates. 

WHO support to European countries

European countries should be ready to detect and manage Zika infection in travellers from affected countries.

Countries where Aedes mosquitoes are present should also prepare to address the risk of Zika's spreading in the spring and summer. European countries can use their experience with dengue and chikungunya to control these mosquitoes. 

WHO advises countries in the Region to strengthen vector control, and surveillance and laboratory detection of Zika virus disease and neurological complications, as well as communications to those at risk. This will help to decrease the presence of Aedes mosquitoes and in turn the risk of Zika's spreading in Europe. 

WHO emergency committee on Zika virus under the International Health Regulations 

WHO Director-General Margaret Chan will convene an emergency committee on Zika virus and observed increase in neurological disorders and neonatal malformations under the International Health Regulations. It will convene via teleconference on Monday, 1 February 2016, to ascertain whether the outbreak constitutes a public health emergency of international concern.