Relapsing fever Borrelia in Ornithodoros ticks from Bolivia.

Abstract

Tick-borne relapsing fever (TBRF), is caused by several species of Borrelia spirochetes, which are transmitted to humans through the bites of Ornithodoros spp. soft ticks. Wild rodents and insectivores are common reservoir hosts. TBRF is responsible for recurring fever associated with spirochetemia. The epidemiology of TBRF has not been well documented in South America where three endemic ticks are suspected to act as vectors (Guglielmone et al., 2006). Ticks referred as Ornithodoros talaje are prevalent in Ecuador, Colombia, Venezuela, Argentina and Brazil, as well as in Guatemala, Panama, Mexico (Guglielmone et al., 2006). This tick was shown to transmit a relapsing fever Borrelia in Panama by human experimentation (Bates et al., 1921). It has been associated with ‘Borrelia mazzottii’ in Mexico (Davis, 1956). This bacterium has, however, been incompletely described, as neither an isolate nor DNA of this bacterium is available (Davis, 1956). Ornithodoros rudis is found in Ecuador, Colombia, Venezuela, Peru, Paraguay and Brazil, and has been associated with ‘B. venezuelensis’ (Davis, 1955). Also, a borrelia called ‘B. brasiliensis’ has been associated with O. brasiliensis in Brazil (Davis, 1952). All three of these borreliae were incompletely described in the 1950s and neither an isolate nor DNA is currently available. In this work, using specific semi-quantitative real-time polymerase chain reaction (PCR) with original primers pairs and probes, we aimed to detect relapsing fever Borrelia spp. in ticks collected in Bolivia.