Efficiency of Anthelmintic Treatment and Its Effect on Microparasite Dynamics in Wild Mastomys natalensis

Co-infections between helminths and microparasites can influence disease dynamics with potential public health implications. However, establishing clear cause-and-effect relationships from natural populations remains challenging. One approach to address this is through perturbation experiments, where a specific parasite is selectively reduced to directly observe its impact on co-infecting parasites. While such experiments have been conducted in wild rodent populations, they have not yet been explored in Africa, despite the continent’s importance for emerging infectious diseases and zoonoses. In this study, we investigated potential helminth-microparasite interactions in wild Mastomys natalensis in Tanzania by using anthelmintics to reduce helminth infections. We first assessed the efficacy of two anthelmintic treatments, ivermectin and pyrantel pamoate, in wild-caught M. natalensis , finding that both treatments significantly reduced gastrointestinal nematodes, with pyrantel pamoate being more effective than ivermectin. Additionally, we examined how helminth reduction influenced microparasite prevalence. Our results show that pyrantel pamoate treatment was associated with a decrease in Morogoro virus seropositivity over time, while anthelmintic treatment had no significant effect on Bartonella infection probability.