Autogenous reproduction by Ornithodoros turicata (Ixodida: Argasidae) females and vertical transmission of the tick-borne pathogen Borrelia turicatae (Spirochaetales: Borreliaceae)

Abstract

Previous research has implicated Ornithodoros ticks, including Ornithodoros turicata, as long-term reservoirs of relapsing fever (RF) spirochetes. Considering the tick's long lifespan and their efficiency in maintaining and transferring spirochetes within the population, the infection could persist in a given enzootic focus for decades. However, little is known about the relative importance of horizontal and vertical transmission routes in the persistence and evolution of RF Borrelia. Our observations on the reproductive biology of O. turicata in the absence of vertebrate hosts indicate an additional mechanism by which Borrelia turicatae can be maintained in the environment. This work establishes the foundation for studying O. turicata reproduction and spirochete-vector interactions, which will aid in devising control measures for Ornithodoros ticks and RF spirochetes.

Keywords: argasid; autogeny; relapsing fever; spirochetes; transovarial transmission.

Fig 1

Collection site of Ornithodoros turicata in Austin, TX, USA. Shown is an aerial view (Google Earth) of the collection site with a scale in the bottom left corner (A). The red dot represents the location where ticks were collected. A container with dry ice was placed by a limestone outcropping and used to bait ticks (B). The white arrow points to the dry ice container. Also shown is a 15 mL tube containing the ticks that were collected (C). Shown on the paper plates is the material from which the ticks were harvested (C).