Seroprevalence for the tick-borne relapsing fever spirochete Borrelia turicatae among small and medium sized mammals of Texas

Abstract

BackgroundIn low elevation arid regions throughout the southern United States, Borrelia turicatae is the principal agent of tick-borne relapsing fever. However, endemic foci and the vertebrate hosts involved in the ecology of B. turicatae remain undefined. Experimental infection studies suggest that small and medium sized mammals likely maintain B. turicatae in nature, while the tick vector is a long-lived reservoir.Methodology/principal findingsSerum samples from wild caught rodents, raccoons, and wild and domestic canids from 23 counties in Texas were screened for prior exposure to B. turicatae. Serological assays were performed using B. turicatae protein lysates and recombinant Borrelia immunogenic protein A (rBipA), a diagnostic protein that is unique to RF spirochetes and may be a species-specific antigen.Conclusions/significanceSerological responses to B. turicatae were detected from 24 coyotes, one gray fox, two raccoons, and one rodent from six counties in Texas. These studies indicate that wild canids and raccoons were exposed to B. turicatae and are likely involved in the pathogen’s ecology. Additionally, more work should focus on evaluating rodent exposure to B. turicatae and the role of these small mammals in the pathogen’s maintenance in nature.

Infestation of small seabirds by Ornithodoros maritimus ticks: Effects on chick body condition, reproduction and associated infectious agents

“…and the pathogenic potential of relapsing fever Borrelia for other vertebrates, including humans, the question of the extent of the circulation of such bacteria arises. Given the growing interest in relapsing fever Borrelia in America and the biomedical tools that may become available to detect the past exposure of hosts by tracking antibody levels (Lopez et al, 2013), investigations could rely on the detection of the Borrelia in ticks, but also sometime more efficiently by detecting antibodies in the vertebrate host (Armstrong et al, 2018).…”

Case report: A retrospective serological analysis indicating human exposure to tick-borne relapsing fever spirochetes in Sonora, Mexico

“…Field studies should be focused at the suspected exposure site to collect serum samples from small and medium-sized mammals, including rodents and domestic and wild canids. These mammals likely have a role in the ecology of TBRF spirochetes [17]. Furthermore, while most Ornithodoros sp.…”

Diversity and distribution of the tick-borne relapsing fever spirochete Borrelia turicatae

“…In support of this, O. turicata ticks have been collected in dens and caves frequented by coyotes [5]. Furthermore, a serosurveillance study indicated grey foxes and coyotes are likely involved in the spirochete's ecology [14]. Sera was acquired from terminally sampled animals and antibody reactivity was determined to B. turicatae protein lysates and the Borrelia immunogenic protein A (BipA) [14], a diagnostic antigen used for TRBF spirochetes [39,40].…”

“…In Texas, B. turicatae was isolated from field collected ticks, sick domestic canines, and a soldier that was conducing field exercises in the state [12,13]. There have also been case studies for the distribution of B. turicatae in rural areas of Texas [9,14,15]. In Florida, spirochetes have been isolated from sick canines in the 1990s [12,16], but little work has followed up on those studies.…”