Synanthropic mammals as sentinels of multi-pathogen circulation at a wildlife-urban interface.

Peri-urban forest fragments used for ecotourism concentrate interactions among wildlife, domestic animals, and humans, creating conditions that favour pathogen transmission through environmental, vector-borne, and trophic pathways. In these landscapes, synanthropic small mammals may act as integrative indicators of pathogen exposure because they interact with wildlife, domestic animals, and human-modified environments. This study conducted multi-pathogen surveillance in synanthropic small mammals to investigate infection patterns at a wildlife-urban interface in a Brazilian ecotourism area. Seventeen individuals belonging to three species (Nectomys squamipes, Didelphis albiventris, and Marmosops incanus) were sampled in a peri‑urban forest fragment. Multiple tissues were screened by PCR assays targeting protozoan, helminth, and bacterial agents, and fecal samples were examined using parasitological techniques for intestinal parasites. Amplicons were sequenced and phylogenetic analyses were performed to support taxonomic assignment. A diverse assemblage of protozoa, bacteria, and helminths was identified, including Toxoplasma gondii, Hepatozoon sp., Babesia sp., Cryptosporidium sp., Cystoisospora spp., Anaplasmataceae (Anaplasma/Ehrlichia-like), hemotropic Mycoplasma, and intestinal trematodes, cestodes, and nematodes (Strongyloides, Syphacia, Toxocara). PCR assays targeting Rickettsia and Bartonella also yielded amplicons, but sequencing did not provide unambiguous confirmation of either genus. Coinfections were frequent, indicating exposure to multiple ecological transmission pathways. These findings support the potential use of synanthropic small mammals as sentinels of pathogen circulation at wildlife-urban interfaces and highlight their relevance for integrated One Health surveillance in rapidly changing peri‑urban landscapes.