The Freehold Area Health Department proposes a multi-faceted approach designed to evaluatethe efficacy of selected plant-derived natural products to control tick vectors of Lyme disease,the most common tick-borne illness in the United States. Identification of all-natural, low toxicitychemicals extracted from botanical sources that are toxic to nymphal Ixodes scapularis(Objective 1) through comprehensive reviews of pertinent literature and collaboration with theDepartment of Forest Products, Oregon State University and the Division of Vector-BorneInfectious Diseases, Centers for Disease Control and Prevention (CDC). Nootkatone showedpromise in New Jersey field trials and will be the initial plant-derived acaricide (PDA) tested, butother candidate compounds with proven acaricidal activity and practically available quantitiesfrom commercial sources adequate for field testing/bioassay within the time frame of the FOAmay be added. Formulation of natural products into water soluble or emulsified compoundsthat can be applied to vegetation and leaf litter in Lyme disease endemic regions (Objective 2)will be addressed through collaboration with Legacy BioDesign, LLC, Loveland, CO and theCDC. Field studies will test a formulation of a nootkatone-based PDA applied against host-seeking nymphal I. scapularis and Amblyomma americanum using two methods (low pressurevs. high pressure hydraulic sprayers) (Objective 3). Combined dragging and walking surveyestimates of tick abundance will be compared between treated plots and untreated edge areasto evaluate whether efficacy is due to direct toxicity or spatial repellency (Objective 4). Trials inthe second year of the study will test the relative effectiveness of single vs. multiple applications,the efficacy of additional PDAs, and/or testing of different dosage rates and formulations. Thethird year of the study will examine the potential role of PDAs in an integrated tick management(ITM) program. A comparative cost analysis will be included in the final year of the study.Assessment of the repellent activity of selected PDAs against host-seeking I. scapularis and A.americanum (Objective 5) will be made in field trials comparing repellency of nootkatone andcommercially available products containing deet and permethrin. Treated tick drags andcoveralls will be exposed along 100-m transects in known tick-infested habitat during the activityperiods of all post-embryonic stages of host-seeking I. scapularis and A. americanum. Project NarrativeLyme disease is the most common tick-borne illness in the United States, with over 181,000confirmed cases reported since 19901 and over 3,372 cases reported in New Jersey during2005 (representing a case rate of 38.58 cases/100,000 population3 and a 25% increase incases over that reported in 2004). While conventional chemical control directed against host-seeking ticks has proven to be the most reliable means of suppressing tick populations,16-26 theuse of habitat-targeted 'hard' acaricides is generally viewed by the public as having undesirableenvironmental impacts, including adverse health risks on humans and pets, ground and surfacewater contamination, and effects on non-target organisms.22,27-29 Development of PDAs and all-natural repellents that are effective against both of these medically-important ticks will providethe public and public health agencies alternatives to conventional chemical control as a meansof reducing human-tick encounters and the incidence not only of Lyme disease, but thetransmission of other emerging tick-borne pathogens.
