New Discovery of Microbe May Lead to Eradication of Malaria
- jiyachatterjee1
- Aug 17, 2020
- 4 min read
By Jiya Chatterjee
If I told you that malaria, one of the world’s most prominent diseases, could be completely eradicated in the near future, would you believe me? Malaria, a disease spread through the bite of female mosquitoes, causes over 400,000 deaths every year, which is about how many deaths COVID-19 has caused in 2020 alone. For years malaria has proven to be very difficult to tackle and suppress. Now, a team in Kenya and the United Kingdom may have found a potential way to control the disease using the help of a newly discovered microbe, Microsporidia MB.
Microsporidia MB is a microbe found in the gut and genitals of mosquitoes. Microsporidia were once thought to be protozoans but are now classed as fungi. This single-celled microbe was found in about 9% of the mosquito population around Lake Victoria, Kenya, and it was found that those mosquitoes were protected from contracting malaria. The name of the type of mosquitoes being studied in Kenya is Anopheles arabiensis, which is commonly found in the sub-Saharan area of Africa, south Asian countries, as well as some areas of South America. While the details of how exactly the Microsporidia MB is preventing mosquitoes from carrying malaria are still not totally clear, it seems that the microbe is able to stop a parasitic protozoan called Plasmodium falciparum from being transmitted. There are three protozoans that cause malaria: Plasmodiumfalciparum, Plasmodium vivax, and Plasmodium malariae. The researchers looked only at Plasmodium falciparum, most likely because Plasmodium falciparum is typically the cause of most malaria cases, and causes about 98% of malaria cases in Africa alone. Essentially, Plasmodium falciparum gets into the system of An. arabiensis mosquitoes by mixing with their saliva in their salivary glands. The Microsporidia in the microbe-infected mosquitoes prevents this mixing of Plasmodium and saliva.
This research is groundbreaking, since progress when it comes to prevention of malaria had come to a halt for some time. "It's a new discovery. We are very excited by its potential for malaria control. It has enormous potential," Professor Steven Sinkins, who is part of the research team working in Kenya and from the MRC-University of Glasgow Centre for Virus Research, told the BBC. In the past there have been potential prevention strategies developed related to other mosquito borne illnesses, but the strategies employed weren’t applicable to malaria. Sterilizing mosquitoes, for example, is one of the leading methods for dengue and Zika prevention, but this is not an option discussed when it comes to malaria prevention. However, regarding malaria, there have been other possible solutions discussed prior to this discovery, such as a bacterium called Wolbachia. These bacteria have many similar characteristics to Microsporidia, including the phenotype that protects mosquitoes from Plasmodium, however it was found that Wolbachia are less efficient, because they are lower intensity bacteria and therefore have less of an effect on the Plasmodium after a while. Microsporidia, on the other hand, works more effectively. There have also been medicinal treatments developed in the past that were used for malaria prevention by giving the medicine directly to humans. For example, chloroquine was used as a standard method for treating and preventing malaria, because it would kill the Plasmodium. However, over time the Plasmodium falciparum has become resistant to the chloroquine, so now it is only given to people traveling to the Middle East or Central America. The reason why Microsporidia MB will not create a similar result is because it doesn’t kill the Plasmodium, it simply blocks it from entering the mosquito’s system, so the Plasmodium won’t genetically change due to the microbe. The chloroquine used to actually kill the Plasmodium, but as with most organisms, due to the fact that there were a few Plasmodiumcells that would survive the chloroquine, evolution cites that over time the majority of the Plasmodium would develop the gene that allows it to defeat chloroquine. Also, Microsporidia is non-pathogenic, meaning that the mosquitoes aren’t harmed by the microbe. For these reasons, Microsporidia is a leading candidate in bringing an end to malaria.
So, how will these results be implemented into becoming an actual solution? In order for this microbe to create a significant impact against malaria, a minimum of 40% of mosquitoes in a region have to carry, or be infected with, Microsporidia MB. It has been found that the microbe can be passed between adult mosquitoes, and that every time a female mosquito has offspring, there is a 45% - 100% chance that it will be transmitted from the female mosquitoes to their offspring, which is an extremely high probability. As such, researchers are looking to employ either of two of their main strategies for increasing the number of mosquitoes infected with Microsporidia. The first option relies on the idea that Microsporidia form spores. Since spores multiply rapidly and exponentially, they can be used to directly infect as many mosquitoes as possible naturally. The second idea involves male mosquitoes. Male mosquitoes don’t bite; however, if they are infected in a lab with the Microsporidia and then released into the wild, they would transmit it to females during intercourse. The pros and cons of each strategy are being examined and discussed for future studies and implementation.
This discovery has given the world a glimmer of hope against a disease which once was considered undefeatable. Introduction of Microsporidia MB in mosquitoes not only will protect human beings from contracting malaria, but it also will not kill mosquitoes, so organisms that rely on mosquitoes as a source of nutrition will not be negatively impacted by the microbe. Who could have imagined that a microbe, a small organism, could solve such big issues. I guess the saying is true after all: sometimes, less is more.
Sources:
Herren, J. K., Sinkins, S. P., & Mbaisi, L. et al. (2020, May 4). A microsporidian
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Gallagher, J. (2020, May 4). Malaria 'completely stopped' by microbe. BBC.
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This is a great summary of a new discovery. Quite rightly you pointed out that covid 19 cannot shift attention from big killers such as Malaria. With climate change, malaria will spread to new parts of the world which are getting hotter.
A very topical subject, well researched and well explained! Good job.