Ticks, capybaras and Spotted Fever: features associated with heterogeneous distribution of Amblyomma sculptum populations infected with Rickettsia rickettsii in the State of São Paulo

• Grant number: 21/06185-9
• Support Opportunities: Scholarships in Brazil - Doctorate
• Effective date (Start): November 01, 2021
• Effective date (End): October 31, 2024
• Field of knowledge: Agronomical Sciences - Veterinary Medicine - Preventive Veterinary Medicine
• Principal Investigator: Marcelo Bahia Labruna
• Grantee: Lina de Campos Binder
• Host Institution: Faculdade de Medicina Veterinária e Zootecnia (FMVZ). Universidade de São Paulo (USP). São Paulo , SP, Brazil

Abstract

Expansion of Brazilian Spotted Fever (BSF) transmission areas in the State of São Paulo has been associated with expansion of capybaras population. Capybaras are the main amplifying hosts of the BSF etiological agent (Rickettsia rickettsii) for Amblyomma sculptum ticks. However, many areas where capybaras and A. sculptum are established remain free of R. rickettsii, suggesting that other factors could be determinant in the establishment of R. rickettsii infection in ticks in a given area. Within this premise, in 2020 we concluded an eco-epidemiological investigation (FAPESP 2013/18046-7, projeto temático) in which three BSF-endemic areas and three non-endemic areas in the State of São Paulo, all associated with capybaras, were evaluated. It was concluded that the endemic areas differed from the non-endemic ones due to the predominance of A. sculptum in the former, in contrast to the predominance of Ambyomma dubitatum in the latter, in addition to the greater general ticks' abundance in endemic areas. Characteristics associated with these differences remain unknown and could explain the heterogeneous distribution of R. rickettsii across A. sculptum populations in the State of São Paulo. Thereby, this project intends to investigate the possible causes associated with R. rickettsii distribution heterogeneity in the State of São Paulo based on the relative abundance of ticks A. dubitatum and A. sculptum estimation and on microenvironmental characteristics assessment in 30 areas inhabited by capybaras in São Paulo State, in addition to investigating the possible interference of the bacterium R. bellii in the establishment of R. rickettsii in tick populations and in the amplifying role of vertebrate hosts. The results will be fundamental for development of BSF prevention and control strategies in the State. (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)

ROMERO, LUIS E.; BINDER, LINA C.; MARCILI, ARLEI; LABRUNA, MARCELO B.. Ticks and tick-borne rickettsiae from dogs in El Salvador, with report of the human pathogen Rickettsia parkeri. TICKS AND TICK-BORNE DISEASES, v. 14, n. 5, p. 8-pg., 2023-05-26. (21/06185-9)