Impacto das mudanças globais na distribuição de Lutzomyia flaviscutellata, vetor de leishmaniose tegumentar na América do Sul, em diferentes escalas espaciais

Abstract

Leishmaniases are neglected tropical diseases transmitted by the bite of infected female sand flies. They are climate-sensitive diseases, being affected by changes in rainfall, temperature and humidity. American Cutaneous Leishmaniasis (ACL) currently faces geographical expansion in Brazil, in transmission patterns associated to anthropic environmental impacts. The transmission of Leishmania (Leishmania) amazonensis by its vector Lutzomyia (Nyssomyia) flaviscutellata is highlighted, being responsible for a severe clinical form of ACL. This thesis aims to evaluate climate and land use change impacts on the distribution of L. flaviscutellata in South America and increase the knowledge of its distribution in different spatial scales. The document is divided in four chapters with studies on: (i) the applications of ecological niche modelling on the evaluation of climate change impacts on the distribution of arthropod vectors; (ii) ecological niche modelling of L. flaviscutellata in climate change scenarios at macroscale in South America; (iii) the importance of environmental variables for the distribution of L. flaviscutellata at mesoscale and its abundance at microscale; (iv) the phlebotomine fauna of a L. (L.) amazonensis transmission area at Pará State, Brazil. An updated list of L. flaviscutellata s occurrence locations in South America is provided, which was used to develop ecological niche models. The models had good predictive performance and their projections under two different climate change scenarios show several areas of potential expansion for L. flaviscutellata in 2050, towards south and southeast in the continent. Climatic variables were the most important for the distribution of L. flaviscutellata at continental scale, especially precipitation, which reinforces the species sensitivity to climate change. At microscale, land use variables gained importance, such as those representing anthropic disturbance in forest environments. The multiple algorithm approach is recommended for the development of ecological niche models and the selection of predictor variables must be adequate to the proposed spatial scale. Studied localities in municipalities Tracuateua and Bragança (Pará State), previously selected by the ecological niche models, present high species richness, with predominance of L. flaviscutellata in forest fragments and its capture at peridomestic sites. The source-sink metapopulation dynamics is suggested for these sand fly populations, where anthropic land use changes control the probability of colonization of peridomestic areas. Four females of L. flaviscutellata were found naturally infected by L. (L.) amazonensis, confirming the circulation of this parasite species in the studied locality, which has records of human cases in a sylvatic and occupational ACL transmission pattern. In conclusion, ecological niche models are effective methods for predicting vector occurrences and can support human health decision makers on disease surveillance and vector control activitie.