Location: Invasive Insect Biocontrol & Behavior Laboratory
Project Number: 8042-32000-012-022-S
Project Type: Non-Assistance Cooperative Agreement
Start Date: Aug 1, 2022
End Date: Sep 30, 2024
Objective:
Research will be carried out to evaluate efficacy of host-targeted chemical acaricides and biopesticides in reducing population density of major tick species of medical and veterinary importance, specifically the blacklegged tick and the lone star tick. Specific objectives include (1) to evaluate new chemical compounds and biopesticides against the immature stages (nymphs and larvae) of the blacklegged tick feeding on the white-footed mouse; (2) to evaluate new chemical compounds and biopesticides against the adults of the blacklegged tick and the lone star tick feeding on the white-tailed deer; and (3) to determine the effects of host-targeted control agents on tick-borne pathogen prevalence in ticks and host animals.
Approach:
Laboratory, semi-field, and field studies will be conducted as appropriate at different stages by Dr. Erika Machtinger of Penn State University with guidance from Dr. Andrew Li of the USDA, ARS. New oral or contact formulations of test materials for this study will be generated and provided either by Dr. Li or the cooperators of Dr. Andrew Li under separate agreements. Work during the first and second years will focus on evaluation of oral formulation of the test compounds against immature ticks feeding on white-footed mice. An existing colony of the white-footed mouse at Dr. Machtinger’s tick research facility will be used. A predetermined dose of test compound will added to mouse food pellets and fed to mice. Animals will be given the same oral dose daily f or a period of 14 days. Blood samples will be collected from individual animals at different times from the starting date until 2 weeks after cessation of oral intake of the test compound. HPLC analysis will be carried out by a commercial testing laboratory to determine the pharmacokinetics of the testing compounds. In the second set of the experiments, mice will be infested with pre-determined number of nymphs or larvae of the black legged tick while animals are fed food pellets dosed with the test compounds. Tick attachment, feeding and survival on animals will be monitored to determine tick mortality as a result of acaricidal compound in host blood. In the third set of the experiments, mice will be infested with field collected blacklegged ticks to determine how the test compound may affect pathogen transmission from infected tick to mice. Conversely, mice will be inoculated with Borrelia pathogen in the laboratory before the effects of test compounds on pathogen acquisition by ticks from infected host animals.
Similarly, test compounds will be evaluated on white-tailed deer using deer raised and maintained at the Penn State University Deer Research Facility. As the white-tailed deer is the end host for the pathogen that causes Lyme disease, only tick control work will be conducted on deer. White-tailed deer will be fed with diet dosed with test compound for a period of 2 weeks. Animals will be infested with adult ticks (males and females) twice, once at the beginning of oral intake of the test compound by the animals and second tick infestation happens after the cessation of oral intake of the test compound by deer. Similarly, blood sample will be taken from deer to determine the pharmacokinetics of the compounds in deer.
Dr. Machtinger will be responsible for securing the permissions for use of the university mouse and deer facilities this research cooperation, including obtaining university IACUC approval for the experimental designs involving white-footed mouse and white-tailed deer that are to be carried out at the university facilities. Dr. Li will provide USDA funding for this work when available to allow the successful completion of the project.
