show Abstracthide AbstractMalaria still remains a huge problem especially in sub-Saharan Africa. There has been a rising need in developing more sustainable and innovative tools. With this in mind, our research team at the International Center of Insect Physiology and Ecology (icipe) sought to identify naturally-occurring malaria-blocking microbes in the Anopheles mosquitoes across several regions of Central and Western Kenyan. This led to the discovery of a new fungi-like obligate intracellular microsporidian species that had not been documented before then and was therefore termed Microsporidia MB. We have shown that this microsporidia symbiont isolated from the malaria mosquito- Anopheles arabiensis, has the capacity to block Plasmodium oocyst development in the mosquito thereby blocking malaria transmission. It is therefore a potential bio-control tool. We have further shown that it is both maternally transmitted from mother to offspring and sexually from infected male to uninfected female or vice versa. Moreover, the symbiont has no adverse effects on the host's health and is mainly localized in mosquito gonads. This project aimed to assemble the first draft genome of the symbiont isolated from ovarian tissues of Anopheles arabiensis progeny of wild-caught mothers with the aim of unraveling its genetic makeup and providing insight into its mechanism of survival in the host.