The Zika virus is transmitted to humans through bites of an infected mosquito of the genus Aedes. This mosquito, also called tiger mosquito, exists in tropical and subtropical regions and also transmits dengue, chikungunya and yellow fever.
The transmission of the virus can also be done in the other direction. Mosquitoes can also become infected by biting someone already infected with the Zika virus. The mosquito then transmits the virus by biting other humans.
In pregnant women, if they are infected with the Zika virus, it can be transmitted by the mother to her child during pregnancy or during delivery. At present, it is difficult to assess the probability of such mother-to-child transmission.
Cases of transmission of Zika virus by breast milk are not yet known.
A possible transmission during sexual intercourse?
There are a few isolated cases where the Zika virus has been transmitted during intercourse. Including that of a North American researcher who transmitted the virus to his wife after becoming infected during a trip to Senegal. But according to the WHO, the evidence of such a transmission is insufficient to justify an alert on this subject. Also, the role of this transmission pathway in the spread of Zika virus is minimal.
Zika virus is transmitted by the tiger mosquito (Aedes albopictus) in some countries. It is particularly recognizable by its black body and its white stripes.
The risk of infection is particularly high in people living in areas where Zika is endemic, for example in some Central and South American countries, and the Caribbean. People at risk are also at risk of infection.