Rickettsial serapositivity in horses and tick vectors species of brasilian spotted fever in the Piracicaba river basin, state of São Paulo

Author(s)

Luciana Bonato de Camargo

• Document type: Master's Dissertation
• Press: Campinas, SP.
• Institution: Universidade Estadual de Campinas (UNICAMP). Faculdade de Ciências Médicas
• Defense date: 2014-11-02

Examining board members

Maria Rita Donalisio Cordeiro; Katia Maria Paschoaletto Micchi de Barros Ferraz; Virgilia Luna Castor de Lima

• Advisor: Maria Rita Donalisio Cordeiro

Abstract

Brazilian spotted fever (BSF) is an acute infectious disease, whose best-known etiologic agent is Rickettsia rickettsii, an intracellular Gran negative bacterium, transmitted by the bite of infected ticks. Several wild and domestic animals play a crucial role in the epidemiology of spotted fever, developing a temporary rickettsemia, allowing the infection to new generations of ticks and also serving as a dispersal vector infected, facilitating transmission to humans. The aim of this work is to study the serapositivity of horses for rickettsiae in areas with and without reported cases of BSF and identify the ticks species presents. Four areas considered with proven BSF transmission were investigated, Amparo, Valinhos, Jaguariúna and Piracicaba, and four areas considered without transmission, San Pedro, Rio Claro, Bragança Paulista and Atibaia, all located in Piracicaba river basin, São Paulo State. Serological survey of horses (n= 54) found in the investigated properties areas was performed using the indirect immunofluorescence assay for antigens R. rickettsii , R. parkeri and R. belli. Among blood sample processed 183 (36.3 %) were reagents, 110 (60,1%) of areas with reported human cases and 73 (39.9 %) of areas without reported human cases. Besides serological survey also 492 ticks of the genus Amblyomma were collected and were found 127 adults species of Amblyomma (25.8 %), 13 Amblyomma dubitatum (2.6%), and 352 nymphs (71,5 %). The investigation of infection by R. rickettsii using the PCR was negative for all ticks collected. The results demonstrated high prevalence of reactive serum of horses in areas with and without reported human cases, highlighting Bragança Paulista and Rio Claro, considerate areas on alert. We emphasize the need for increased monitoring and research in the counties with no reported cases. The highest prevalence of the species A. cajennense in all areas of study reinforces the hypothesis of the risk of BSF occurrence in al municipalities (AU)

• FAPESP's process: 12/02447-0 - Rickettsia infection in equines and species of tick vectors of Brazilian Spotted Fever in the Piracicaba River Basin, State of São Paulo
• Grantee: Luciana Bonato de Camargo
• Support Opportunities: Scholarships in Brazil - Master