Morphometric and Molecular Insights into spp. in Wild and Synanthropic Rodents from Southern and Southeastern Brazil.

Small rodents are known hosts of various pathogens, including , but until now, in Brazil, only has been described in these animals. In this study, liver samples and blood smears were obtained from 289 rodents belonging to 14 Cricetidae and two Muridae species that had been captured in municipalities of the states of Paraná and Rio de Janeiro. Smears were stained with Giemsa, and gametocytes were detected via microscopy in 10.72% ( = 31/289) of samples, with these individuals representing three rodent species. Significant morphometric differences were observed in gametocyte measurements in rodents. Using conventional PCR, spp. 18S rDNA fragments were amplified in 24.91% ( = 72/289) of samples, with those individuals representing seven rodent species. Phylogenetic analyses clustered 41 sequences from this study into a subclade with other sequences from small mammals in Brazil, identifying four distinct haplotypes, and, for the first time, a relationship between haplotype and gametocyte length was observed. Based on phylogenetic analysis, this study reinforces the trophic relationship between rodents and reptiles as a possible link in the transmission cycle in South America. Furthermore, our findings expand knowledge on spp. hosts, describing and as new host species and identifying two novel circulating haplotypes in rodents from Paraná State, southern Brazil.