NATIVE AND EXOTIC SMALL MAMMALS AS HOSTS OF Hydatigera taeniaeformis SENSU STRICTO LARVAE ON PIG FARMS OF CENTRAL ARGENTINA: A STUDY OF PREVALENCE AND PHYLOGENETIC RELATIONSHIPS.

Small mammals, including those inhabiting human-modified habitats, transmit zoonotic diseases such as cysticercosis. This disease is caused by Cysticercus fasciolaris, the larval form of species within the Hydatigera taeniaeformis s.l. group. While the life cycle of these flatworms is well understood, certain aspects of their phylogeny remain unknown. Studies in Europe, Asia, and Africa suggest that the species Hydatigera taeniaeformis s.s. exclusively infects small mammals of the family Muridae. However, no studies have been conducted in the Americas until now. In this study, small mammals were captured on 18 pig farms in the province of Buenos Aires throughout a year. Necropsies of captured individuals were performed, and the presence of cysts was recorded. The prevalence of cysticercosis was analyzed for the entire assemblage, with species as the explanatory variables. Species-specific prevalence was also modeled, considering season and type of farm as the explanatory variables. Cysts were collected from Akodon azarae, Oligoryzomys flavescens, Rattus novergicus, and Rattus rattus identified through molecular techniques, comparing their DNA sequences with those stored in GenBank for phylogenetic hypothesis. A total of 460 small mammals were analyzed, including the introduced species R. novergicus, R. rattus, and M. musculus and the native species A. azarae, O. flavescens, Oxymycterus rufus, Didelphis albiventris, and Lutreolina crassicaudata. The prevalence of cysticercosis was similar between species, and it showed a seasonal association in R. norvegicus and A. azarae. Phylogenetic analysis confirmed the presence of Hydatigera taeniaeformis s.s. in cricetids, suggesting a recent spillover event associated with European colonization in the Americas. [ABSTRACT FROM AUTHOR]