Culex mosquito cannot transmit Zika, say Brazilian scientists

Zee Media Bureau

Brasilia: Brazilian scientists on Tuesday said that the common mosquito known as Culex cannot transmit the Zika virus.

At a press conference in Rio de Janeiro, scientists from the Oswaldo Cruz Institute said that a study carried out with the Pasteur Institute in Paris had ruled out the Culex as a vector, Xinhua news agency reported.

Culex is 20 times more common than the Aedes aegypti mosquito, which is the main vector of Zika. The Aedes also transmits dengue fever and chikungunya.

The teams analysed 1,600 mosquitoes collected from five different regions across Brazil. Half were Culex and half were Aedes aegypti. They were tested to determine their suitability as Zika vectors.

The scientists mixed the two groups together and fed them jointly with blood carrying the Zika virus.

They found that between 80 and 100 per cent of the Aedes aegypti carried the virus, with a great quantity in their saliva. However, none of the Culex mosquitoes showed the same result.

"We examined the saliva of the common mosquito to see if we could detect the virus but we found no Zika. This convinced us that this mosquito is not capable of transmitting it," said Ricardo Lourenco, a veterinarian from the the Oswaldo Cruz Institute, who led the project.

This study contradicted findings in July from the state-owned Oswaldo Cruz Foundation, in which researchers said the Zika virus had been found in the saliva of the Culex though its ability to transmit the virus remained unknown.

They concluded that the Culex quinquefasciatus mosquito has not played a role in the Zika epidemic that has hit Brazil over the last year. Brazil has been one of the countries worst hit by Zika though cases have dropped significantly in recent months after a massive fumigation campaign and with the arrival of winter.

The results were published Tuesday in the PLoS (Public Library of Science) Neglected Tropical Diseases.

(With IANS inputs)