The dissemination potential of Microsporidia MB in Anopheles arabiensis mosquitoes is modulated by temperature

Microsporidia MB , a vertically transmitted endosymbiont of Anopheles mosquitoes, shows strong potential as a malaria control agent due to its ability to inhibit Plasmodium development within the mosquito host. To optimize its deployment in malaria transmission reduction strategies, it is critical to understand how environmental factors, particularly temperature, affect its infection dynamics. In this study, we investigated the influence of four temperature regimes (22°C, 27°C, 32°C, and 37°C) on Microsporidia MB prevalence and infection intensity by rearing mosquito larvae under controlled laboratory conditions. Our results demonstrate that elevated temperatures, especially 32°C, significantly enhance both larval growth and Microsporidia MB infection rates. Population growth modeling further indicates that at 32°C, an infected mosquito population can reach 1,000 offspring within 15–35 days—representing a 4.7-, 1.3-, and 1.7-fold higher dissemination potential compared to 22°C, 27°C, and 37°C, respectively. Despite a higher mortality rate at 32°C (approximately 20% greater than at 27°C), this temperature emerged as the most favorable for mass-rearing Microsporidia MB -infected larvae. These findings offer the first insights into temperature-mediated dynamics of Microsporidia MB and support its potential for scalable implementation in malaria-endemic regions.