ABSTRACT
Abstract To a better insight into the epidemiology and genetic diversity of protozoan hemoparasites infections in wild mammals, this study aimed to the post mortem detection of DNA from species of the order Piroplasmida (Babesia sp., Cytauxzoon sp., and Theileria sp.) and suborder Adelorina (Hepatozoon sp.) using polymerase chain reaction based on the 18S rRNA gene followed by genetic sequencing of blood and spleen samples collected from carcasses of 164 free-ranging and captive wild mammals from Mato Grosso state. Among them, one Leopardus pardalis, three Panthera onca, two Puma concolor were positive for Cytauxzoon sp., and six Tapirus terrestris tested positive for Piroplasmida, while one L. pardalis was positive for Hepatozoon sp. Furthermore, an uncharacterized piroplasmid genetically related to Theileria sp. previously detected in cats from Brazil was described in lowland tapirs. Despite the controversy regarding the epidemiological threat of these protozoa, the detection of these tick-borne agents in wild free-living and captive mammals, even when asymptomatic, demonstrates the importance of monitoring, particularly in hotspots such as the state of Mato Grosso, to verify the circulation and genetic diversity, to anticipate the possible emergence of diseases, and even their consequences to other animals as well as humans.
Resumo Para uma melhor compreensão da epidemiologia e diversidade genética das infecções por hemoprotozoários em mamíferos selvagens, este estudo teve como objetivo a detecção post mortem de DNA de espécies da ordem Piroplasmida (Babesia sp., Cytauxzoon sp. e Theileria sp.) e subordem Adelorina (Hepatozoon sp.), utilizando-se a reação em cadeia pela polimerase, baseada no gene 18S rRNA, seguido de sequenciamento genético de amostras de sangue e baço, coletadas de 164 carcaças de mamíferos selvagens de vida livre e cativos do estado de Mato Grosso. Entre eles, um Leopardus pardalis, três Panthera onca, dois Puma concolor foram positivos para Cytauxzoon sp., e seis Tapirus terrestris testaram positivos para Piroplasmida, enquanto um L. pardalis foi positivo para Hepatozoon sp. Além disso, foi descrito em antas, um piroplasmídeo não caracterizado geneticamente, relacionado à Theileria sp., previamente detectado em gatos do Brasil. Apesar da controvérsia quanto à ameaça epidemiológica desses protozoários, a detecção desses agentes em mamíferos silvestres e cativos, mesmo quando assintomáticos, demonstra a importância do monitoramento, principalmente em hotspots, como no estado de Mato Grosso, para verificar a circulação e a diversidade genética, a fim de antecipar o possível surgimento de doenças e, até mesmo, suas consequências para outros animais, bem como os humanos.
Subject(s)
Animals , Cats , Babesia/genetics , Piroplasmida/genetics , Panthera , Phylogeny , Brazil , DNA, Protozoan/geneticsABSTRACT
Species identification using DNA sequences is the basis for DNA taxonomy. In this study, we sequenced the ribosomal large-subunit RNA gene sequences (3,037-3,061 bp) in length of 13 Chinese Theileria stocks that were infective to cattle and sheep. The complete 28S rRNA gene is relatively difficult to amplify and its conserved region is not important for phylogenetic study. Therefore, we selected the D2-D3 region from the complete 28S rRNA sequences for phylogenetic analysis. Our analyses of 28S rRNA gene sequences showed that the 28S rRNA was useful as a phylogenetic marker for analyzing the relationships among Theileria spp. in ruminants. In addition, the D2-D3 region was a short segment that could be used instead of the whole 28S rRNA sequence during the phylogenetic analysis of Theileria, and it may be an ideal DNA barcode.