ECOLOGICAL NICHO MODELING OF PHLEBOTOMINAE SPECIES AND ITS RELATIONSHIP WITH THE DISTRIBUTION OF AMERICAN TEGUMENTARY LEISHMANIOSIS IN THE ENDEMIC REGION OF SOUTHEAST BRAZIL
Name: VIVIANE COUTINHO MENEGUZZI
Type: PhD thesis
Publication date: 29/11/2016
Advisor:
Name |
Role |
|---|---|
| ALOÍSIO FALQUETO | Advisor * |
Examining board:
| Name |
Role |
|---|---|
| ALOÍSIO FALQUETO | Advisor * |
| ANGELICA ESPINOSA BARBOSA MIRANDA | Internal Examiner * |
| BLIMA FUX | Co advisor * |
| CRISPIM CERUTTI JUNIOR | Internal Examiner * |
| GUSTAVO ROCHA LEITE | External Alternate * |
Pages
Summary: Cutaneous leishmaniasis (CL) is caused by a protozoan of the genus Leishmania and is transmitted by sand flies. The State of Espírito Santo (ES), an endemic area in the Southeast of Brazil, has shown considerably high prevalence in recent decades, allowing the expansion of the disease to unaffected areas. Computer tools, such as ecologic niche modelling (ENM), are useful for predicting potential disease risk. In this study, ENM was applied to species of sand flies and CL cases in ES to identify the principal vector and risk areas of the disease, aiming to understand the early origin and expansion of this disease. Sand flies were collected in 466 rural localities between 1997 and 2013 in the three hours after dusk using a combination of active and passive capture. Insects were identified to the species level, and the localities were georeferenced. All medical records of autochthonous cases of CL attended at the University Hospital Cassiano Antonio de Moraes (HUCAM) between 1978 and 2013 were evaluated. Twenty-one environmental databases were selected from WorldClim. Maxent was used to construct potential distribution models for Nyssomyia intermedia, Nyssomyia whitmani, Migonemyia migonei, Evandromyia lenti, Pressatia choti and CL cases. ENMTools was used to overlap the species and the CL case models. The KruskalWallis and chi-square tests were performed, adopting a 5% significance level. Approximately 250,000 specimens captured represented 43 species. Of the 1,472 autochthonous cases recorded, 10.8% presented mucosal lesion. The area under the curve (AUC) was considered acceptable for N. intermedia, N. whitmani, M. migonei, E. lenti, P. choti and the CL cases. The slope was considered relevant for all species and CL cases models. The overlay test identified N. intermedia as the main vector of CL in the study area. There is evidence of the existence of a primitive wild cycle of LTA in Atlantic forest areas in Southeastern Brazil. It is possible that Leishmania (Viannia) braziliensis has been transferred from the Amazon region to the Atlantic forest areas, for thousands of years, through forest corridors linking the two biomes. There were differences between the probable site of infection of patients, indicating that there was CL expansion to the east of the ES, possibly caused by the intensification of migration for the Metropolitan area of ES. Spatial modelling tools enable an analysis of the association among environmental variables, vector distributions, and CL cases in ES. Further, they allow better understanding of the factors related to the CL geographical expansion in colonized areas of the Southeast of Brazil.
