The presence of Wolbachia bacteria in Aedes aegypti has the capacity to reduce the yellow fever virus transmission in this species of mosquito. This discovery is the theme of an article published by Gates Open Research. The research which resulted in this article, named “Pluripotency of Wolbachia against Arbovirus: the case of yellow fever”, was supervised by Fiocruz researcher and World Mosquito Program (WMP) leader in Brazil, Luciano Moreira. WMP is an international program that fights diseases spread by mosquitoes and, in Brazil, it is conducted by the Foundation.

The article is a result of the combined work of researchers from three different institutions: René Rachou Institute (IRR/Fiocruz Minas), Ezequiel Dias Foundation (Funed), and the Federal University of Minas Gerais (UFMG). Click here for access.

The urban transmission of the disease through Aedes aegypti has not been reported in Brazil since 1942. However, researchers point out the existence of a risk of yellow fever re-urbanization, once Aedes aegypti is present in the majority of tropical and subtropical cities around the world, and it was the main vector in the past. Between 2016 and 2018, Brazil faced some yellow fever outbreaks, arboviruses, transmitted by wild mosquitoes of the genera Haemagogus and Sabethes. The mortality rate was up to 30%. Currently, in addition to yellow fever, the Wolbachia method is efficient to prevent the transmission of the following arboviruses: dengue, zika, chikungunya, and mayaro fever. 

The study

In order to perform the research, two isolated groups of yellow fever virus (YFV) were used. They were obtained from humans and monkeys, originating from the last outbreaks in the state of Minas Gerais. These viruses were multiplied in an insect cell culture and added to the blood feed of Aedes Aegypti with and without Wolbachia. Since the blood samples used in the feed could contain antibodies due to, for example, vaccine against the disease, the samples were processed to ensure these antibodies were eliminated prior to feeding the mosquitoes.

Source: Fiocruz News Agency (AFN).