Antibodies against rickettsiae from spotted fever groups in horses from two mesoregions in the state of Santa Catarina, Brazil

A.P Medeiros,V Bellato,M.B Labruna,A Vieira-Neto,A.A Sartor,A.P Souza,J Moraes-Filho,A.B Moura

doi:10.1590/s0102-09352013000600019

Abstract

Bacteria of the Rickettsia genus are agents of Brazilian Spotted Fever (BSF), a zoonotic disease which is difficult to diagnose, evolves quickly and can result in death. Antibodies against Rickettsia spp. in horses were studied, by means of Indirect Immunofluorescence Assay (IFAT ≥64), in 150 blood samples taken from animals in two Santa Catarina mesoregions (Planalto Serrano and Vale do Itajaí). The overall occurrence of Rickettsia spp. antibodies in horses was 18.66%, with cross-reactivity occurring in all positive samples for at least two of the species tested. Separately, according to the species, 25 (16.66%) samples were positive for R. rickettsii, 15 (10%) for R. parkeri, 22 (14.66%) for R. amblyommii, 23 (15.33%) for R. rhipicephali, 16 (10.66%) for R. bellii and 19 (12.66%) for R. felis. Only two animals resulted in a conclusive serodiagnosis, one for R. bellii and the other for R. rickettsii, at maximum dilutions of 1:4096 and 1:512, respectively. The occurrence of antibodies against Rickettsia spp. in horses from two mesoregions in the state of Santa Catarina indicates the movement of BSF agents in these sentinel animals and confirms the importance of studying spotted fever in the state of Santa Catarina.

Highlights

Spotted fever is a zoonotic disease that is difficult to diagnose and can be confused with other diseases
The samples were sent to the Laboratory of Parasitic Diseases in the Department of Preventive Veterinary Medicine and Animal Health (VPS) at the Faculty of Veterinary Medicine and Zootechny (FMVZ), University of São Paulo (USP), where they were processed for indirect immunofluorescence using isolated rickettsiae as antigen in Brazil: R. rickettsii strain Taiaçu, R. parkeri strain At24, R. amblyommii strain Ac37, R. rhipicephali strain HJ5, R. bellii strain Mogi and R. felis strain Pedreira
There is evidence, through the IFAT in horses, of the presence of R rickettsii, R. parkeri, R. amblyommii, R. rhipicephali, R. bellii and R felis, in areas where cases of spotted fever have been reported in Santa Catarina (Vale do Itajaí), and in areas where there are no official reports of this disease

Summary

Introduction

Spotted fever is a zoonotic disease that is difficult to diagnose and can be confused with other diseases. Species of bacteria of the Rickettsia genus are responsible for this human disease, which evolves rapidly and can result in death. Rickettsiae have been diagnosed in all continents, with widespread distribution in tropical and subtropical regions. In Brazil, they have been detected in the Southeast, South and Northeast regions, but have a higher occurrence in Minas Gerais and São Paulo. In Minas Gerais, from 1981 to 2000, 50% of cases of spotted fever resulted in death, constituting an epidemic in the state (Fonseca and Martins, 2007). From 1985 to 2000, a total of 47 spotted fever cases were diagnosed in São Paulo (Lima et al, 2001).

Methods

Results

Conclusion