Biology subjects

Churcher, T.

Publications and source records attributed to Churcher, T..

3 recordsLinked to original sources

bioRxiv2026

Suppression of Plasmodium falciparum infection by Microsporidia MB in wild Anopheles arabiensis populations

Symbiont-based approaches offer a promising strategy for reducing malaria transmission by suppressing Plasmodium development in Anopheles mosquitoes. Microsporidia MB, a naturally occurring microsporidian symbiont of Anopheles arabiensis, inhibits Plasmodium falciparum development in the laboratory, but its efficacy under natural transmission conditions is unknown. Here we monitored Microsporidia MB in wild An. arabiensis over 30 months in western Kenya and identified distinct low- and high-intensity infection phenotypes consistent with horizontal and vertical transmission, respectively. Overall, Microsporidia MB was associated with approximately 50% lower odds of P. falciparum infection. This association strengthened with symbiont intensity: high-intensity infections were associated with approximately 60% lower odds of Plasmodium infection compared with approximately 34% for low-intensity infections, identifying symbiont intensity as a key determinant of parasite-blocking efficacy. These findings provide evidence that Microsporidia MB suppresses P. falciparum infection in wild Anopheles populations, providing a key component of the field validation needed to advance Microsporidia MB as a candidate for malaria-control applications.

microbiology↗

bioRxiv2024

Near-infrared spectroscopy discriminates mass-reared sterile and wild tsetse flies

In the frame of the Pan African Tsetse and Trypanosomosis Eradication Campaign, an integrated pest management approach has been adopted to manage tsetse fly populations using a sterile insect technique (SIT).. Monitoring the efficacy of the SIT programs requires the discrimination between wild and sterile males collected in monitoring traps. The discrimination between sterile and wild males relies mainly on marking of sterile males with a fluorescent dye powder (before the releases) and their identification using a fluorescence camera and /or a fluorescence microscope. However, the accuracy of this method remains limited with defective marking and wild flies contaminated with a few dye particles in the monitoring traps. The molecular techniques developed to discriminate doubtful flies are costly for endemic countries. Here, we investigate the ability of a new generation monitoring tool, the near-infrared spectroscopy (NIRS) to discriminate between lab-reared Glossina palpalis gambiensis and their counterparts in the field. NIRS technique discriminates wild flies males with 86% accuracy to Glossina palpalis gambiensis males reared in an insectarium. Interestingly, the prediction accuracy between wild and laboratory-reared flies improved to 88% when the Glossina lab colony flies were irradiated. In light of these results, NIRS can discriminate tsetse flies even when identification with the UV camera is doubtful. However, more investigations integrating some natural variables are required before the validation of the technical as a complementary method for potential future tsetse eradication programs.

evolutionary biology↗

bioRxiv2019

High Plasmodium infection intensity in naturally infected malaria vectors in Africa

The population dynamics of human-to-mosquito malaria transmission in the field has important implications for the genetics, epidemiology and control of malaria. The number of oocysts in oocysts positive mosquitoes developing from a single, naturally acquired infectious blood meal (herein referred to as parasite exposure) greatly influence the effectiveness of transmission blocking interventions but still remains poorly documented. During a year-long analysis of malaria parasite transmission in Burkina Faso we caught and dissected wild malaria vectors to assess Plasmodium oocysts prevalence and load (the number of oocysts counted in mosquitoes with detectable oocysts) and the prevalence of salivary gland sporozoites. This was compared to malaria endemicity in the human population assessed in cross-sectional surveys. Data was analyzed using a novel transmission mathematical model to estimate the per-bite transmission probability and the average parasite exposure of mosquitoes for each location. Observed oocysts load and estimated parasite exposure in naturally infected mosquitoes is substantially higher than previous estimates (ranging from 3.2 to 24.5 according to seasons and locations) and indicates a strong positive association between parasite exposure of mosquitoes and parasite prevalence in human. This work suggests that highly infected mosquitoes may have a greater influence on the epidemiology and genetics of the parasite and that novel partially effective transmission blocking interventions may become more effective at halting transmission as parasite exposure is diminished.

ecology↗