Researchers at the International Centre of Insect Physiology and Ecology (icipe) in Nairobi, Kenya, have made a new discovery that will boost efforts in the fight against Malaria.
The breakthrough paves way for the control of the killer disease using a newly discovered microbe that blocks the transmission of the disease from mosquitoes to people.
In a study published on 28 July 2021 in Frontiers in Microbiology the researchers show that the microbe, Microsporidia MB, can be transmitted sexually between mosquitoes, in addition to being passed from mother mosquitoes to their offspring, as reported in the Centre’s previous study.
“This breakthrough will allow the efficient spread of the microbe through mosquito populations, thus limiting their ability to infect people with the parasite that causes malaria,” said the researchers.
In early 2020, Icipe and partners made the groundbreaking finding that malaria mosquitoes containing Microsporidia MB are unable to transmit malaria.
The researchers found the microbe, which is related to fungi, occurring naturally inside the cells of the malaria-transmitting Anopheles mosquitoes in parts of Kenya.
By studying the ways through which it is propagated between mosquitoes, the researchers believe they will be able to develop an effective tool for controlling malaria.
In the recent study, the scientists show that Microsporidia MB is efficiently transferred between adult mosquitoes during mating. Also, the microbe naturally accumulates in the reproductive organs of male mosquitoes, indicating that it has adapted to spread through mosquito populations through mating.
“In last year’s publication, icipe showed that Microsporidia MB is passed from female mosquitoes to their offspring. We have now built on these results to demonstrate that the microbe also has another transmission route; from adult to adult,” notes Tracy Maina, an icipe MSc student involved in the research.
“When considering the use of the microbe as a tool for malaria control, the key challenge is increasing Microsporidia MB levels in wild mosquito populations. Therefore, unearthing a new transmission route is of great significance,” adds Dr Jeremy Herren, icipe scientist who led the study.
Herren and his team plan to use these results as part of a strategy to increase the spread of Microsporidia MB through mosquito populations in locations in Kenya, thus controlling the spread of malaria in humans.
In particular, the researchers are exploring the feasibility of releasing male mosquitoes laden with Microsporidia MB in areas of high malaria transmission. As male mosquitoes do not bite people, they do not pose any malaria-transmission risk.
These males would continue with their natural life cycle, infecting wild female mosquitoes with the microbe, which would, in turn, infect their offspring with the malaria blocking trait.
Targeted release of infected male mosquitos and the spread to females and their offspring could initiate a continuous infection cycle across mosquito generations. The result would be a largely self-maintaining and sustainable strategy for malaria control.
Malaria continues to be a major health threat across Africa, with this region accounting for 93% of the global malaria deaths.
Since 2005 there has been an unprecedented success in malaria control, but progress has stagnated in more recent years with case levels remaining the same between 2014 and 2016 and increasing between 2016 and 2017.