The new research comes from the University of Maryland and the research finding have been described as significant in terms of future malaria control strategies. The types of mosquito populations that could be partially reduced by the introduction of the fungus includes insecticide-resistant strains of the bug. Mosquitoes becoming resistant to insecticides is one of the major challenges faced by organizations seeking to control malaria in affected regions.
What is also significant about the study is that this is not simply a laboratory study with potential application – the new data relates to filed studies using natural mosquito populations. These studies were conducted in Burkina Faso, West Africa.
Scientists demonstrate that a naturally occurring fungus, which has been genetically engineered to deliver a toxin to mosquitoes, can effectively safely reduce mosquito populations by more than 99 percent in a simulated village setting.
Malaria is a mosquito-borne infectious disease that affects humans and other animals, caused by a parasite known as Plasmodium (of which there are several species). Malaria infection, which is spread by the female Anopheles mosquito, represents a major global problem. World Health Organization figures indicate there are some 429,000 malaria deaths each year, affecting tropical and subtropical regions.
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While there have been some effective international efforts to reduce malaria, there are also some pockets of worsening trends. These areas are often locales where conditions are challenging difficult due to conflict or other causes of poor access to the populations.
To begin the study, scientists identified a fungus called Metarhizium pingshaense, which tends to infect the types of mosquitoes that spread malaria. They then proceeded to modify the fungus to turn it into a mosquito killing machine.
For this the researchers took a toxin found in the venom of a species of Australian Blue Mountains funnel-web spider. The genetic instructions for making the toxin were identified and then added to the fungus’s genetic code. This led to a modified fungus that is capable of manufacturing the toxin once it has entered a mosquito.
After demonstrating the rapid ability of the fungus to infect and kill mosquitoes, the fungus was tested out in a controlled study, selecting a village area in west Africa. Screens were erected around the village to contain a selected number of mosquitoes (1,000 adult male and 500 adult female mosquitoes). Inside the enclosure, experimental huts, plants, small mosquito-breeding pools were fitted and a food source for the mosquitoes. Also positioned were black cotton sheets and sesame oil (mixed with the transgenic fungus M. pingshaense); the sheets were designed to attract the mosquitoes.
With evaluating the success of the trial, the Burkina Faso study showed mosquito populations collapsed by 99 percent within 45 days. According to Dr Brian Lovett, from the University of Maryland: “The transgenic fungus quickly collapsed the mosquito population in just two generation.”
The researcher adds: “Our technology is not aiming to drive the extinction of mosquitoes, what we’re aiming to do is break malaria transmission in an area.”
The researcher points out that the aim is to control malaria and not to wipe out mosquito populations completely. The next phase is to repeat the test on a larger scale.
The research has been published in the journal Science. The research paper is titled “Transgenic Metarhizium rapidly kills mosquitoes in a malaria-endemic region of Burkina Faso.”
This article is part of Digital Journal’s regular Essential Science columns. Each week Tim Sandle explores a topical and important scientific issue. Last week we considered how microbiome research has revealed a connection between our microorganisms and anxiety symptoms.
The week before we learned how the original kilogram is no more, or at least it will remain locked in a Paris vault never to be used for official purposes, such as calibrating national weight standard again. Instead there’s a new approach for assessing global mass based on a mathematical logarithm.