Infecção natural e análise molecular de tripanosomatídeos em diferentes espécies animais no estado do Rio Grande do Norte

Abstract

The study analyzed the occurrence of natural infection by Trypanosoma cruzi and Leishmania spp. using molecular markers and phylogenetic analysis in blood clots from domesticated animals in the state of Rio Grande do Norte. Blood clot samples were collected from 163 blood samples from sheep, goats, horses, cattle, and dogs, as well as 64 popliteal lymph node aspirates from dogs in nine municipalities in the state of Rio Grande do Norte (RN). Initially, natural infection by T. cruzi using 18S and kDNA was observed in blood clot samples from sheep, goats, and horses, with the parasite identified in 28.3% (17/60), 22.7% (5/22), and 15.4% (2/14) of the samples, respectively. These animals were distributed across the three mesoregions studied throughout the state of RN. At this point, infection in horses was described for the first time in Brazil. Subsequently, the report of a dog in the acute phase of T. cruzi infection was related to clinical, hematological, biochemical, parasitological, and characterization of the isolate using biological, molecular, and phylogenetic methods. A seemingly asymptomatic young dog exhibited a prolonged period of patent parasitemia, normocytic and hypochromic anemia. In addition, cardiac damage in this animal was observed due to the high concentration of biomarkers such as troponin I, NT-ProBN, and qualitative segmental hypokinesis. Other dog blood clot samples were also subjected to T. cruzi kDNA amplification and showed 10.9% (7/64) positivity. Phylogenetic analysis of a sheep blood clot sample revealed DNA sequences closely correlated with DTU II samples. Meanwhile, the parasite isolated from the dog in the acute phase was genetically characterized by three markers and phylogenetic analysis as TcIII. DTU III, initially described in the wild environment, is increasingly present in the domestic cycle in the Brazilian semiarid region. Data from dog samples revealed that popliteal cultures in biphasic medium were positive in 12.5% (8/64) of the samples, with flagellated forms resembling promastigotes. Sequencing and phylogenetic analysis of eight culture samples showed similarity above 99% with Leishmania infantum sequences. The widespread distribution of T. cruzi and Leishmania infantum infection in domesticated animals contributes to the expansion of the epidemiological landscape and the need to better understand the role of these animals in the transmission cycle as reservoirs and/or sentinels of infections in humans.