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Tick vectors and tick‐borne disease are increasingly impacting human populations globally. An important challenge is to understand tick movement patterns, as this information can be used to improve management and predictive modelling of tick population dynamics. Evolutionary analysis of genetic divergence, gene flow and local adaptation provides insight on movement patterns at large spatiotemporal scales. We develop low coverage, whole genome resequencing data for 92 blacklegged ticks, Ixodes scapularis, representing range‐wide variation across the United States. Through analysis of population genomic data, we find that tick populations are structured geographically, with gradual isolation by distance separating three population clusters in the northern United States, southeastern United States and a unique cluster represented by a sample from Tennessee. Populations in the northern United States underwent population contractions during the last glacial period and diverged from southern populations at least 50 thousand years ago. Genome scans of selection provide strong evidence of local adaptation at genes responding to host defences, blood‐feeding and environmental variation. In addition, we explore the potential of low coverage genome sequencing of whole‐tick samples for documenting the diversity of microbial pathogens and recover important tick‐borne pathogens such as Borrelia burgdorferi. The combination of isolation by distance and local adaptation in blacklegged ticks demonstrates that gene flow, including recent expansion, is limited to geographical scales of a few hundred kilometres. [ABSTRACT FROM AUTHOR]

The entomopathogenic nematode Steinernema riobrave has moderate impact on larval cattle fever tick, Rhipicephalus microplus, at semi-field conditions. Weekly foliar applications of in vitro-reared S. riobrave (BASF- Nemasys-R) sprayed on tick-infested potted buffelgrass killed significantly more larval ticks than water or the no treatment check (P<0.05). Use of a native nematode species like S. riobrave that occurs in the South Texas environment and has few, if any, effects on native flora/fauna is favored by conservation-focused organizations, especially in areas inhabited by threatened or endangered species. Additional research is proposed to evaluate impact of Nemasys-R at pasture conditions. Effective pasture treatment for questing R. microplus larvae is critical to support the USDA-APHIS Cattle Fever Tick Eradication Program in South Texas. El nemátodo entomopatógeno Steinernema riobrave tiene un impacto moderado sobre las larvas de la garrapata de la fiebre del ganado, Rhipicephalus microplus, en condiciones de semi campo. Las aplicaciones foliares semanales de S. riobrave (BASF-Nemasys-R) criado in vitro sobre pasto buffel en macetas infestado de garrapatas mataron significativamente más larvas de garrapatas que el agua o el control sin tratamiento (P<0.05). El uso de una especie de nemátodo nativo como S. riobrave, que se encuentra en el medio ambiente del sur de Texas y tiene pocos efectos, si es que tiene alguno, sobre la flora/fauna nativa, y es favorecido por organizaciones centradas en la conservación, especialmente en áreas habitadas por especies amenazadas, o en peligro de extinción. Se proponen investigaciones adicionales para evaluar el impacto de Nemasys-R en las condiciones de los pastos. El tratamiento eficaz de los pastos para las larvas de R. microplus es fundamental para apoyar el Programa de Erradicación de la Fiebre del Ganado del USDA-APHIS en el sur de Texas. [ABSTRACT FROM AUTHOR]

Background: Soft ticks (Family: Argasidae) are vectors of relapsing fever Borrelia in the United States and are potential vectors of African swine fever virus, a pathogen that could have a devastating effect on the U.S. swine industry if introduced to the U.S. mainland. Much of the tick-borne disease research in the U.S. focuses on hard ticks, and less is known about the ecology of soft ticks. Some soft tick species found in the southern U.S. have a wide host range and may feed on cattle, swine, native and exotic ungulates, small mammals, reptiles, and humans. Because the feeding habit of most soft tick species involves taking short, repeated blood meals that may include multiple host species, pathogen transmission among hosts is a concern both for human and animal health. Materials and Methods: Sampling was carried out at four locations in south Texas using dry ice traps placed in or near animal burrows and other sheltering cracks and crevasses that may provide refuge for soft ticks. Collected ticks were identified and subsequently screened for Rickettsia and Borrelia species and for host bloodmeal detection using conventional polymerase chain reaction and Sanger sequencing for pathogen and host species identification. Results: In total, 256 ticks of two Ornithodorinae species were screened. Borrelia species were identified in three samples. Bloodmeal detections were made in 22 tick specimens, representing eight vertebrate host species. Conclusions: Results demonstrate that the soft tick species detected herein feed on a range of wildlife hosts in south Texas and are associated with agents of human disease.