Clezia Siqueira de Lima

The microbial communities associated with muscid flies have gained increased attention due to their changing composition across developmental stages, which is significantly influenced by environmental factors and available food sources. In this context, Musca domestica L. stands out as one of the most relevant species, primarily recognized as a mechanical vector of infectious agents, including bacteria, protozoa, and viruses. Some of these agents can be transmitted to humans and animals, causing disease, largely due to the species frequent association with decomposing organic matter and contaminated environments, thereby facilitating the dissemination of microorganisms. Among the microorganisms that share these same environments, the eukaryotic protozoan genus Acanthamoeba deserves special attention. However, despite this environmental coexistence, current knowledge regarding Acanthamoeba species and their interactions with insects remains limited and fragmented, highlighting the need for further studies to clarify the specific role of flies in the epidemiology of Acanthamoeba infections. In this context, the occurrence of Acanthamoeba species. was investigated in wild populations of M. domestica. Flies were collected using traps distributed throughout the FIOCRUZ/RJ campus. 14 (28%) of the 50 flies examined tested positive for Acanthamoeba and were identified as genotype T4 by Sanger sequencing of the 18S rRNA gene, a genotype commonly associated with keratitis. Active Acanthamoeba trophozoites were detected in the intestines of five flies. These findings reinforce the importance of understanding the ecological relationship between Acanthamoeba and M. domestica, given the potential role of these flies as environmental vectors in the dissemination of pathogens that may impact human health.