Diversity and distribution of helminth communities of the rodent Akodon montensis Thomas, 1913 (Rodentia: Cricetidae: Sigmodontinae) in preserved and altered environments in the Atlantic Forest, Brazil

The conversion of natural landscapes into agricultural and urban areas results in vegetation loss and habitat fragmentation, affecting biodiversity and favoring generalist species, such as <i>Akodon montensis</i>. This rodent species acts as a reservoir for zoonotic agents and harbors various parasites, including helminths, which are important indicators of environmental changes. The present study analyzed the structure, composition, and diversity of the helminth community of <i>A. montensis</i> in the Atlantic Forest, considering four locations in the state of São Paulo, Brazil. We calculated parasitological parameters (abundance, intensity and prevalence of infection) for each helminth species and evaluated helminth diversity within and between each individual host. In addition, we assessed the influence of type of environment (preserved forest or altered matrix) and host characteristics (sex and body size) on parasitological parameters of helminth species and on helminth diversity. A total of 64 individuals of <i>A. montensis</i> were analyzed, of which 60.9 % were infected with at least one helminth species. Nine species were collected, including eight nematodes and one cestode. No influence of the type of environment and host characteristics was observed on the parasitological parameters of some helminth species (e.g., <i>Protospirura numidica criceticola</i>, <i>Rodentolepis akodontis</i>, <i>Stilestrongylus eta</i> and <i>Syphacia</i> (<i>Syphacia</i>) <i>carlitosi</i>) and on the diversity of helminths within each individual host. A low effect of the type of environment on the diversity of parasites was observed among infracommunities. As an opportunistic species, <i>A. montensis</i> can exploit a wide range of resources and environmental conditions, making it less susceptible to variations in parasite diversity across habitats. These findings reinforce the importance of investigating parasite fauna in different landscapes to understand the impacts of anthropization on host-parasite interactions.