Culex mosquito off the hook in Zika virus transmission in Brazil

Culex quinquefasciatus mosquitoes, previously thought to play a key role in the rapid spread of the Zika virus in Brazil, have been ruled out of any involvement in the epidemic. A study carried out by the Instituto Oswaldo Cruz (attached to the Brazilian Ministry of Health), in collaboration with the Institut Pasteur, has recently demonstrated in the lab that Culex mosquitoes are incapable of transmitting the Zika virus.

The Zika virus emerged in north-western Brazil in May 2015 and has since spread across the continent surprisingly quickly and extensively. Two mosquito species were suspected to be behind this epidemic: the Aedes aegypti mosquito, well known for transmitting several viruses such as dengue and chikungunya, and the Culex quinquefasciatus mosquito, which is rife in urban areas. But no Culex mosquitoes naturally infected by the Zika virus have actually been found in the field. And a new laboratory-based study carried out by the Instituto Oswaldo Cruz, in collaboration with the Arboviruses and Insect Vectors Unit directed by Anna-Bella Failloux at the Institut Pasteur, has now confirmed the theory that this species is not responsible for the Zika epidemic that is raging in the country.

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