Breakthrough: Microbe found to block malaria transmission

The malaria disease burden remains a major impediment to economic development over many regions of sub-Saharan Africa. Large-scale insecticide treated net (ITN) distribution campaigns over the previous 15 years have reduced malaria cases by an estimated 40%. However, progress has plateaued; between 2014 and 2016 global incidence remained essentially the same. This a strong indication that current control measures are insufficient and additional novel strategies to control Anopheles mosquito populations or their capacity  to transmit Plasmodium parasites are needed if we are to make further inroads in reducing malaria incidence.

The outcome of vector–pathogen interactions can be influenced by symbiotic microbes. Notably, symbionts can prevent disease vectors from transmitting pathogens that are agents of human disease. This can be developed into a novel vector management strategy; symbionts are disseminated into vector populations to limit their capacity to transmit human disease.

In a research done, Scientists found that microsporidia MB, a fungi-like organism which occurs naturally in malaria-carrying mosquitoes, stops malaria transmission, but does not kill the mosquito. Researchers found this symbiotic microsporidia at moderate levels in wild Anopheles arabiensis mosquitoes in Kenya. When these mosquitoes were fed Plasmodium falciparum-infected blood, the microsporidia prevented the formation of oocysts in the mosquito. Sporozoites, the form of the parasite that are injected into humans during a blood meal, develop within oocysts. Disrupting oocyst formation, therefore, disrupts malaria transmission. The problem is that microsporidia MB is found in less than 10% of wild Anopheles arabiensis mosquitoes in Kenya, with greatest prevalence after peak rainfall. The aim now is to design ways to increase the presence and dissemination of this microsporidia so it can disrupt transmission.