Population structure and dynamics of free-living capybara associated with tick infestation and Rickettsia spp. infection

• Grant number: 17/00117-6
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• Start date: March 01, 2017
• End date: February 28, 2019
• Field of knowledge: Agronomical Sciences - Veterinary Medicine - Preventive Veterinary Medicine
• Principal Investigator: Marcelo Bahia Labruna
• Grantee: Hermes Ribeiro Luz
• Host Institution: Faculdade de Medicina Veterinária e Zootecnia (FMVZ). Universidade de São Paulo (USP). São Paulo , SP, Brazil
• Associated research grant: 13/18046-7 - Capybaras, ticks, and spotted fever, AP.TEM

Abstract

Brazilian Spotted Fever (BSF) caused by the bacterium Rickettsia rickettsii and transmitted by the tick Amblyomma cajennense is the tick-borne disease of greatest medical importance in Latin America. In the interior of São Paulo State, the BSF-endemic areas are associated with capybaras, the primary host for A. cajennense in these areas. However, there are much more areas where A. cajennense populations are sustained by capybaras, and without the occurrence of BSF. Also, there are areas inhabited by A. cajennense and capybaras, in which for a given period of time there was no disease endemism, and thereafter these areas became endemic to BSF. With the aim to elucidate these gaps in the BSF epidemiology, the present proposal is composed by 9 subprojects that will investigate ecologic interactions of BSF, the tick vector, and the capybara. For this purpose, capybara populations, ticks, and the associate wild and domestic fauna will be evaluated simultaneously for 4 consecutive years in 3 BSF-endemic, and 3 non-endemic areas of the state of São Paulo, and also in two areas of high fauna and flora diversity in the Pantanal biome. In addition, several studies on experimental infection of ticks and capybaras with R. rickettsii will be done to simulate field situations. The results of this project will provide a better understanding on the dynamics of the R. rickettsii infection and the occurrence of BSF in the state of São Paulo. Finally, a mathematical model on the R. rickettsii circulation in tick and capybara populations will be constructed, what will indicate the minimum reproduction rate of capybaras that would allow the maintenance of R. rickettsii infection in tick populations. This model will have direct application in official programs of management and control of capybara populations, aiming to work on the prevention of new cases of BSF in the endemic areas, and at the same time, to prevent non-endemic areas to become endemic for BSF over time. (AU)

Scientific publications

(References retrieved automatically from Web of Science and SciELO through information on FAPESP grants and their corresponding numbers as mentioned in the publications by the authors)

PECKLE, MARISTELA; LUZ, HERMES R.; LABRUNA, MARCELO B.; SERPA, MARIA CAROLINA A.; LIMA, STANLEY; MATURANO, RALPH; FACCINI, JOAO L. H.; MCINTOSH, DOUGLAS. Multi-locus phylogenetic analysis groups the New World bacterium Rickettsia sp. strain ApPR with the Old World species R. africae; proposal of ``Candidatus Rickettsia paranaensis{''}. TICKS AND TICK-BORNE DISEASES, v. 10, n. 6, OCT 2019. (17/00117-6)

LUZ, HERMES R.; RAMIREZ-HERNANDEZ, ALEJANDRO; BENATTI, HECTOR R.; RAMIREZ, DIEGO G.; SZABO, MATIAS P. J.; LABRUNA, MARCELO B.. Comparative survival of the engorged stages of Amblyomma dubitatum and Amblyomma sculptum in the laboratory: Implications for Brazilian spotted fever epidemiology. TICKS AND TICK-BORNE DISEASES, v. 11, n. 2, MAR 2020. (13/18046-7, 13/13650-3, 17/00117-6)

PECKLE, MARISTELA; LUZ, HERMES R.; LABRUNA, MARCELO B.; SERPA, MARIA CAROLINA A.; LIMA, STANLEY; MATURANO, RALPH; FACCINI, JOAO L. H.; MCINTOSH, DOUGLAS. Multi-locus phylogenetic analysis groups the New World bacterium Rickettsia sp. strain ApPR with the Old World species R. africae; proposal of "Candidatus Rickettsia paranaensis". TICKS AND TICK-BORNE DISEASES, v. 10, n. 6, p. 8-pg., 2019-10-01. (17/00117-6)