Spotted fever rickettsiae, Ehrlichia and Anaplasma, in ticks from peridomestic environments in Panama

Abstract

Rickettsiae and rickettsial diseases have been known in Panama since the 1950s, when five cases of Rocky Mountain spotted fever (RMSF) were reported from the vicinity of Ollas Arriba, Trans-Isthmus Highway and Panama City (reviewed in [1]). In the following 20 years, Rickettsia rickettsii was isolated from two patients who died of RMSF and pools of Amblyomma cajennense. Serosurveillance conducted in nine provinces of Panama during the 1980s established a relatively high seroprevalence (5.4–15.2%) by complement fixation using R. rickettsii antigen [2], a prevalence that greatly exceeds the low frequency of RMSF cases recognised in Panama. Inoculation of several pools of Amblyomma caused seroconversion to spotted fever group (SFG) rickettsiae in guinea pigs; however, R. rickettsii was not isolated from infected guinea pigs, suggesting that other rickettsial agents may be present in Panama. The importance of the tick-borne rickettsial diseases in Panama emerged recently after several fatal cases were repeatedly reported in the rural area, west of the Panama canal ([1]; J. Motta, 2007, personal communication). The purpose of this work was to assess the presence and prevalence of Rickettsia and Anaplasmataceae in ticks from peridomestic sites in Panama. MATERIALS AND METHODS