MOLECULAR IDENTIFICATION OF COCCIDIANS OF WILD BIRDS: THE APPLICABILITY OF SOME MITOCHONDRIAL GENIC REGIONS IN SPECIES DIFFERENTIATION AND PHYLOGENETIC ANALYSIS
oocysts, morphology, morphometry, sequencing, phylogeny, Neotropical birds.
Coccidians are obligate intracellular protozoans that infect most invertebrates, all classes of vertebrates, including domestic and wild animals and humans. They present intestinal life cycles, although extra-intestinal life stages are observed in some species. They are usually identified from fecal samples. Brazil has a diverse avifauna currently represented by 1,971 species of different orders. Passeriformes is the most representative order that is often positive for different species of coccidian parasites, mainly of the genera Isospora Schneider, 1881 and Eimeria Schneider, 1875. The study of the interactions between these parasites and hosts allows us to understand several ecological, evolutionary and behavioral processes, including sexual selection, reproductive success, migration, competitiveness, among others. Currently, there are several techniques and methodologies that can be applied to identify a coccidian species in addition to morphological analysis, from confirmation of host susceptibility, determination of parasite density, degree of pathogenicity and identification of inter- and intra-specific differences that provide relevant taxonomic adjustments. Finally, the advent of Molecular Biology, a recognized and established practice, mainly in the study of coccidian parasites in production animals, offers complementary information to microscopy and immunological methods, for example, since the sequencing of the microorganism's DNA serves as an additional study to taxonomy and phylogeny. Based on these facts, this work, in chapters I, II, III and IV, aimed to genetically identify coccidians from wild birds captured in the Atlantic Forest regions of southeastern Brazil, demonstrating the isolation of coccidia oocysts from fecal samples of wild birds, with subsequent DNA extraction in order to amplify and sequence different genic regions of the cox1, cox3 genes and fragments of the small and large subunit of the rDNA of the mitochondrial DNA, evaluating the applicability of these new sequences in the differentiation of species and phylogenetic studies.