Location: Livestock Arthropod Pest Research Unit
2025 Annual Report
Objectives
Objective 1: Improve and develop surveillance and monitoring methods to more efficiently apply measures for controlling invasive/exotic tick populations that are pests of livestock and wildlife.
Sub-objective 1.A: Increase understanding of invasive tick ecology and interactions with the environment including alternative hosts.
Objective 2: Exploit tick biology, behavior, and ecology to develop and improve management techniques for controlling invasive/exotic ticks including novel acaricides, repellants, attractants, and genetic approaches such as vaccines and gene silencing.
Sub-objective 2.A: Identify the function of unique targets within the tick for development of novel control strategies such as gene silencing, vaccines, and biopesticides.
Sub-objective 2.B: Characterize tick cholinesterases and define their role in impacting the immune response at the tick-host interface.
Objective 3: Devise and assess methods to deploy newly developed control strategies such as novel acaricides, repellants, attractants, biocontrol agents, vaccines and gene silencing for controlling invasive/exotic ticks on livestock and wildlife hosts.
Objective 4: Understand the impact of changing climate on the range, movement, and suitable habitat of invasive/exotic tick pests of livestock and wildlife including the lone star tick, Asian longhorned tick, winter tick, and tropical bont tick to reduce their impact on production.
Sub-objective 3.A: Evaluate delivery technologies to enhance the use of RNAi-based biopesticides targeting ticks.
Sub-objective 3.B: Evaluate antigen delivery platforms for anti-tick vaccine candidates that have potential for protection against multiple tick species.
Sub-objective 3.C: Investigate desiccant dust-based acaricides as a tool for integrated management of tick ectoparasites on cattle.
Objective 4: Understand the impact of changing climate on the range, movement, and suitable habitat of invasive/exotic tick pests of livestock and wildlife including the lone star tick, Asian longhorned tick, winter tick, and tropical bont tick to reduce their impact on production.
Sub-objective 4.A: Explore cold-stress in a three-host tick to identify possible genetic signatures contributing to survivorship.
Sub-objective 4.B: Explore heat-stress in a one-host tick to identify possible genetic signatures contributing to survivorship.
Approach
Ticks that parasitize livestock and wildlife pose a continuing threat to animal and human health worldwide. Tick infestations of livestock impact animal production both directly (e.g., decreased weight gain and milk production) and indirectly (e.g., disease causing pathogens transmitted by ticks, treatment costs), collectively resulting in annual economic losses that can exceed USD $700 million. Further, the expanding distribution of both native and invasive ticks in the US is a significant concern. The overall goal of our project is to provide tools and technologies that directly assist producers and the public with more effectively combatting these tick species on a regional and national level. Ticks on livestock have traditionally been managed by acaricide application, but more environmentally conscious alternatives are needed for inclusion within integrated tick management programs. Surveillance and monitoring of current tick diversity and distribution are critical, especially given the projected changes in future climatic variables that will likely alter biotic and abiotic factors that drive tick population success. Using a multi-disciplinary approach, we will: evaluate the role of understudied hosts in sustaining tick populations; identify targets in the tick that can be used to develop cross-species tick control technologies; evaluate methods for the delivery of tick control technologies; and explore whether genetic signatures of tick thermal tolerance could be used as a feasible tool to predict a species’ potential for range expansion. The outcomes of our research will broadly inform strategies that reduce the negative impacts of all major ticks of livestock and provide viable tools for our producers and the public.
Progress Report
This report summarizes research progress continued under the bridging project 3094-32000-044-000D, “Management of Ticks of Veterinary Importance,” which began October 1, 2021 and terminated September 30, 2024. This bridging project is in effect while the next five-year research plan, 3094-10400-002-000D, “Biology, Management, and Surveillance of Ticks of Veterinary Importance,” completes the Office of Scientific Quality Review certification process.
In support of Objective 1, our group established a new strain of the winter tick using field specimens collected from hunter-harvested white-tailed deer, and this strain is being propagated on a bovine host for future projects. The next project cycle will involve repeated, simultaneous infestations of cattle with lone star tick adults and winter ticks. As such, we have refined our methods to optimize the placement and sequence of tick patches and stockinettes to accommodate upcoming research needs. To support a whole-genome sequencing project and assist with diploid genome assembly, we conducted single-pair mating of adult lone star ticks originating from two different geographic backgrounds. Larval and nymphal progeny from these mate pairs were propagated, and the resulting F1 adults will be used as part of a ‘trio-binning’ genome assembly method. ARS researchers in Kerrville, Texas, collaborated with researchers at the University of California San Diego to identify genes expressed by the winter tick that are sex-biased and have a potential role in sex determination and that can be manipulated to suppress tick populations. Collectively, these protocols and data will support upcoming studies on tick thermal tolerance.
In support of Objective 2, ARS researchers in Kerrville, Texas, collaborated with University of Nevada-Reno researchers to evaluate the activity of novel tick promoters that are of interest for tick transgenesis. This was completed using a luciferase-based reporter assay, developed by ARS researchers in Kerrville, Texas, for use in tick cell lines.
ARS researchers in Kerrville, Texas, collaborated with researchers at Thomas Jefferson University in Philadelphia, Pennsylvania, and the University of Texas Medical Branch in Galveston, Texas, to evaluate a vaccine construct, based on an inactivated rabies backbone, for its immunogenicity in cattle. Preliminary results indicate that cattle produce antibodies to both the backbone and the vaccine target antigen, conferring rabies protection and providing a promising alternative to antigen presentation for anti-tick vaccines.
Accomplishments
1. Same tick, different host. Ticks and tick-borne diseases threaten human and animal health, placing a societal and economic burden on the United States. Integrated tick management approaches are essential to reduce populations of pathogen-transmitting ticks. Since ticks require hosts as a bloodmeal source, host-targeted strategies are an effective approach for reducing tick populations. However, it is possible that a single tick species parasitizing different hosts may exhibit distinct host-dependent traits, subsequently impacting relevant control approaches. To implement host-targeted control efforts, these populations must first be identified. Using a population genetics approach, ARS researchers in Kerrville, Texas, demonstrated that blacklegged ticks do not display evidence of host-associated populations. As such, similar control efforts can be applied to all hosts harboring these ticks. In contrast, host-associated populations were identified for American dog ticks, which is critical information for deploying host-targeted control approaches. Collectively, this work empowers vector-borne disease programs by providing a way to target populations associated with competent reservoir hosts more efficiently.
Review Publications
Oliva-Chavez, A., Gonzalez-Gonzalez, J., Harvey, C., Ribiero-Silva, C., Leal-Galvan, B., Persinger, K.A., Durski, S., Olafson, P.U., Johnson, T.L. 2025. Identification of Amblyomma americanum antigens after vaccination with tick extracellular vesicles in white-tailed deer. Vaccines. https://doi.org/10.3390/vaccines13040355.
Tietjen, M., Esteve-Gasent, M.D., Castro-Arellano, I., Li, A.Y., Medina, R. 2024. Lack of host-associated differentiation in Ixodes scapularis using population genetics. Entomologia Experimentalis et Applicata. https://doi.org/10.1111/eea.13533.
Gonzalez, J., Harvey, C., De Souza Ribeiro-Sil, C., Leal-Galvan, B., Persinger, K.A., Olafson, P.U., Johnson, T.L., Oliva Chavez, A. 2024. Evaluation of tick salivary and midgut extracellular vesicles as anti-tick vaccines in white-tailed deer (Odocoileus virginianus). Ticks and Tick Borne Diseases. https://doi.org/10.1016/j.ttbdis.2024.102420.
Alhawsawi, M., Lewis, D.A., Frigard, R., Smith, E.M., Sivakumar, J., Sharm, A., Nantz, A.R., Sabile, C., Kennedy, J., Loni, R., Lefevre, G., Vaka, A., Leanza, Q., Kelley, M., Stacey, C., Santhosh, R.A., Catlett, N., Cady, T., Rizvi, R.S., Wagner, Z., Olafson, P.U., Benoit, J. 2025. Developmental stage and level of submersion in water impact the viability of lone star and winter tick eggs during flooding. Journal of Medical Entomology. https://doi.org/10.1093/jme/tjae143.
Edwards, R.T., Antoshechkin, I., Hill, E., Perry, M.W., Olafson, P.U., Saelao, P., Lohmeyer, K.H., Akbari, O.A. 2025. Transcriptome analysis of the winter tick (Dermacentor albipictus) reveals sex-specific expression patterns and identifies doublesex as a potential target for genetic control. G3: Genes, Genomes, Genetics. https://doi.org/10.1093/g3journal/jkaf116.