Location: Tick and Biting Fly Research2011 Annual Report
1a. Objectives (from AD-416)
Objective 1: Determine if new commercial insecticidal toxicants could be useful as acaricides in the eradication program. Sub-obj. 1.A. Evaluate use of currently available insecticide mixtures that might result in additive or synergistic effects to enhance efficacy in the control of ticks. Sub-obj. 1.B. Evaluate use of long-lasting acaricides for use in regulatory activities of the CFTEP. Sub-obj. 1.C. Evaluate novel methods of acaricide delivery for cattle fever tick control. Objective 2: Develop operationally useful plans for resistance management in fever tick infestations. Sub-obj. 2.A. Evaluate use of Co-Ral for its ability to eradicate organophosphate (OP)-resistant fever ticks in pasture conditions. Sub-obj. 2.B. Characterize emerging resistance to ivermectin and new acaricides in fever tick populations in Mexico. Sub-obj. 2.C. Establish and implement a diagnostic facility to monitor acaricide resistance, define mechanisms of resistance, and provide management strategies for controlling outbreak strains. Objective 3: Develop wildlife-based strategies to eradicate ticks on premises with infested deer, including research on ecology application of anti-tick vaccines and chemicals, novel delivery methods and field trials. Sub-obj. 3.A. Classify habitat preferences of white-tailed deer and cattle fever ticks in Zapata County, TX, using satellite imagery. Sub-obj. 3.B. Analyze genetic associations among populations of southern cattle ticks and cattle ticks, on cattle, white-tailed deer, and other captive and wild ungulates. Sub-obj. 3.C. Evaluate efficacy of ARS-Patented '4-Poster' Deer Treatment Bait Station and medicated baits to eradicate cattle fever ticks feeding on white-tailed deer in infested premises in South Texas. Sub-obj. 3.D. Evaluate efficacy of new acaricides formulated for the '4-Poster' and other topical treatment devices to control blacklegged and lone star ticks feeding on white-tailed deer and cattle fever ticks feeding on deer in infested premises in South Texas. Sub-obj. 3.E. Further develop and field test ARS-Patented Automatic Collaring Device for potential use in applying acaricidal neckbands to control all species of ticks that feed on white-tailed deer. Sub-obj. 3.F. Develop and field test slow-release long-lasting acaricidal neckband formulations for application to deer by the automatic collaring device. Sub-obj. 3.G. Describe relative importance of white-tailed deer as alternative hosts for the dispersal and maintenance of cattle fever tick populations. Objective 4: Perform research to support development of spatial models of adverse economic impact of re-infestation of fever ticks on Texas, other potentially infested states, and the U.S. cattle industry as a whole. Objective 5: Determine risk of Babesia transmission by ticks. Sub-obj. 5.A. Test for presence of Babesia in fever tick outbreak strains in south Texas. Sub-obj. 5.B. Using molecular techniques, evaluate both wild and captive white-tailed deer and exotic ungulates for the presence of Babesia. Sub-obj. 5.C. Determine if Rhipicephalus microplus can acquire Babesia from white-tailed deer and subsequently transmit Babesia to naive cattle.
1b. Approach (from AD-416)
This project addresses the biology and control of ticks of veterinary and human importance with an emphasis on developing technologies to help maintain eradication of cattle fever ticks and the agents that they transmit causing potentially fatal bovine babesiosis and to reduce the risk of humans contracting tick-borne diseases including Lyme disease and human ehrlichiosis. It is a multi-disciplinary project requiring scientists from a wide range of academic specialties, backgrounds, and experiences. The research approach is composed of 5 major objectives including: 1) to evaluate commercially available pesticides for use in the fever tick eradication program, 2) to monitor pesticide resistance in cattle fever ticks and develop plans to mitigate outbreaks of resistant ticks, 3) to develop and evaluate technologies and strategies to eradicate cattle fever ticks or control other tick species feeding on white-tailed deer and other wild ungulates, use satellite image analysis to classify deer habitat preferences, analyze genetic associations among fever ticks and hosts, and to elucidate the relative importance of white-tailed deer as alternative hosts for cattle fever ticks, 4) to continue data input, organization, and development of the GIS database of current and historical fever tick infestation data used to develop descriptive and predictive epidemiological models of fever tick outbreaks, and 5) to determine the risk of Babesia transmission by ticks, including the potential for wild and feral ungulates to serve as reservoir hosts.
3. Progress Report
Research accomplished during the second year of this five-year project has contributed significantly toward meeting the objectives designed to effect control of ticks of veterinary and human importance, primarily by developing technologies and methods for host-targeted control of ticks on cattle and white-tailed deer. This multifaceted project that addresses discovery, data collection, and analyses supporting these studies employs scientific expertise from a variety of disciplines including entomology, acarology, chemistry, ecology, molecular biology, molecular genetics, geography, remote sensing, and immunology. A study to develop and evaluate medicated feed supplement blocks to prevent ticks from feeding on cattle was highly successful, with no ticks of any stage being detected on cattle from the fourth week of treatment through the remainder of the 40-week study. ARS scientists continued to collaborate with scientists at Texas A&M University Kingsville on a multi-year project to evaluate the role of white-tailed deer in compromising the fever tick eradication program and to improve deployment strategies and efficacy of self-treatment technologies developed and patented by ARS to control ticks feeding on white-tailed deer. ARS personnel continued to acquire and enter data into the ARS Cattle Fever Tick GIS Databases that compile numerical and geographic data of current and historical eradication intervention efforts. ARS queries these databases to provide APHIS with detailed maps of regulated premises, geo-spatial boundaries, and summary spatial data of Temporary Preventative Quarantines defined by the Texas Animal Health Commission. ARS continued collaborations with industrial partners to engineer improvements to thermal polymer attachment and detachment modules for neckbands used with the ARS-patented automatic deer collaring device. Re-engineered parts were manufactured and are being field-tested to evaluate function and durability. In collaboration with scientists at Northern Arizona University, genetic markers were identified that can be used in genetic studies of spatial associations among geographic populations of fever ticks, and additional microsatellite loci that may be similarly useful in these studies were identified from genomic DNA. The question of whether cattle fever ticks from white-tailed deer and cattle are genetically similar was addressed by evaluating three locations where ticks were collected from deer and cattle in the same or neighboring pastures. Genetic structure was low or absent between ticks from deer vs. cattle, indicating the ticks were using both hosts equally, i.e., there was no host specificity. ARS scientists also are studying deer that are repeatedly infested with ticks while held under conditions that prevents the deer from grooming. Biological samples including blood and biopsies at tick attachment sites have been collected and are being analyzed to describe the immune response of deer to repeated tick infestation. The effect of repeated infestation on the ability of ticks to produce viable eggs is also being assessed.
Davey, R.B., Pound, J.M., Klavons, J.A., Lohmeyer, K.H., Freeman, J.M., Perez De Leon, A.A., Miller, R. 2011. Efficacy and blood sera analysis of a long-acting formulation of moxidectin against Rhipicephalus (Boophilus) microplus (Acari: Ixodidae) on treated cattle. Journal of Medical Entomology. 48(2):314-321.