Ecological aspects of Brazilian Spotted Fever in an endemic area in the State of São Paulo

Author(s)

Adriano Pinter dos Santos

• Document type: Doctoral Thesis
• Press: São Paulo.
• Institution: Universidade de São Paulo (USP). Faculdade de Medicina Veterinária e Zootecnia (FMVZ/SBD)
• Defense date: 2007-03-16

Examining board members

Marcelo Bahia Labruna; Fernando Ferreira; Luis Fábio Silveira; Rodrigo Martins Soares; Matias Pablo Juan Szabo

• Advisor: Marcelo Bahia Labruna

Abstract

Brazilian Spotted Fever (BSF) is a tick-borne-disease caused by the bacterium Rickettsia rickettsii. An ecological study was conducted in a BSF-endemic area in Taiaçupeba County, Mogi das Cruzes Municipality, State of São Paulo. With the purpose to determine natural hosts of the immature stages of the tick vector Amblyomma aureolatum, a total of 243 wild animals were captured in two fragments of Atlantic Forests between January and December of 2005. Pitfall trap stations were used for capture of rodents and small didelphids while tomahawk traps were used for Didelphis aurita capture. Mist nets (14m x 3m each) were used for bird capture. Captured animals were scarified and blood, spleen and liver were extracted. Spleen samples were submitted to molecular and bioassay tests for rickettsia research. Captured ticks were submitted to morphological or molecular taxonomic identification and to rickettsia research. Ticks from the genera Amblyomma, Haemaphysalis and Ixodes were collected. Immature tick stages of A. Aureolatum were collected on three individuals of the bird species Pyriglena leucoptera, but no other A. Aureolatum tick was found infesting neither rodents or didelphids. No animal was found infected by rickettsiae whereas three rickettsiae, two of them belonging to Spotted Fever Group, were found infecting the ticks Amblyomma longirostre, Ixodes aragaoi and Ixodes loricatus. No tick was found infected by R. Rickettsii, the agent of BSF. The present study revealed details about the A. Aureolatum life cycle in natural conditions, contributing for a better understanding about the enzootic cycle of BSF. (AU)