Brazil has developed a new type of genetically modified mosquitoes, with defective spermatozoa that results in sterile eggs, in its fight against mosquito-borne diseases, local media reported on Thursday.

The altered mosquitoes would be produced for initial trials in September thanks to the research carried out by the University of Sao Paulo's (USP) Biomedical Sciences Institute, Agencia Brasil reported.

The Aedes aegypti mosquitoes are known vector that spread Zika, dengue, chikungunya and yellow fever. If curbing the reproduction of the Aedes aegypti mosquito is effective, the new mosquito variety would then be given to the United Nations for distribution to other countries, the agency said.

A second phase of trials would also be needed, said professor Margareth Capurro. "Because when we made a genetic modification, in addition to the characteristics we want, we might have induced unwanted characteristics," she said.

She estimated that by the end of 2019, researchers could produce 500,000 mosquitoes a week to fight the diseases.

Brazil is already using a type of modified mosquitoes which will never reach maturity to fight the mosquito-borne diseases.