Aspectos moleculares e caracterização fenotípica de isolados dermotrópicos e viscerotrópicos de um novo grupo de tripanossomatídeos

• Ano de defesa: 2018
• Autor(a) principal: Santana, Alynne Karen Mendonça de
• Orientador(a): Almeida, Roque Pacheco de
• Tipo de documento: Tese
• Tipo de acesso: Acesso aberto
• Idioma: por
• Programa de Pós-Graduação: Pós-Graduação em Ciências da Saúde
• Palavras-chave em Português: Ciências da saúde; Leishmania; Leishmanioses; Leishmaniose-like; Crithidia; Tripanossomatídeos
• Área do conhecimento CNPq: CIENCIAS DA SAUDE
• Link de acesso: http://ri.ufs.br/jspui/handle/riufs/7637

Trypanosomatid protozoa of Leishmania genus are vector-borne parasites that infect humans causing a wide range of diseases known as Leishmaniasis. Severity of clinical forms generally depends on infecting species, thus its correct identification becomes critical to diagnosis, prognosis and treatment. The current biochemical and molecular methods for typing strains of Leishmania species are mostly effective. Although these tools remain important in the diagnosis and identification of Leishmania, they are insufficient for definitive identification. After isolate 7 clinical parasites strains, some of them belonging to atypical cases of cutaneous/mucocutaneous and visceral Leishmaniasis, we aimed to identify the specie of Leishmania involved in these cases. By combining structural analysis of the body shape, such as presence of flagellum and kinetoplast, we saw that these parasites shared morphologic characteristics with others Tripanosomatidae, however, they were not conclusive for species identification. Since PCR and isozymes assays were unsuccessful to identify 6 out of 7 clinical isolates reported here, we proceeded to determine their genome sequence. Through whole-genome sequencing analysis of parasite strains, we showed that a new pathogenic Trypanosomatid was the etiological agent in clinical cases diagnosed as Leishmaniasis in Brazil. By comparing coding sequences of over orthologous genes within 36 Trypanosomatidae organisms, we found that this new parasite is closely related to Crithidia fasciculata, which parasites exclusively mosquitoes and is considered non-infective to humans. Phenotypic characterization of 2 of these isolates from the skin and bone marrow of the same patient showed that skin isolate was attenuated compared to the bone marrow isolate for survival in the spleen in BALB/c mice. However, both of them were able to infect and induce inflammation in the liver after 4 and 6 weeks post infection. Conversely, only skin isolate was able to survive in dermis, leading to ear swelling, accompanied of presence of parasites in the ear and lymph nodes. Besides that, bone marrow isolate infection in murine macrophages showed higher number of infected cells and also increased number of parasites within macrophages comparing to the skin isolate infection. Furthermore, bone marrow isolate negatively modulated the nitric oxide production in murine macrophages, corroborating with increased infection. Our findings raise concerns about an emerging infectious disease easily confused with Leishmaniasis, opening a research path towards epidemiological questions about identification of vectors, reservoirs, distribution and reassessment of Leishmaniasis cases in Brazil. Due to its proximity to the monoxenous Crithidia genus and the geographical location of atypical Leishmaniasis cases reported here, we proposed naming this new parasite species as Cridia sergipensis. Overall, this research provides a unique knowledge on phenotipic differences associated with diverse pathologies caused by Cridia infection.