Evaluation of repellency and toxicity of novel botanical compounds against the blacklegged tick and the lone star tick

The blacklegged tick (Ixodes scapularis) and the lone star tick (Amblyomma americanum) are among the most important vectors of tick-borne pathogens disease affecting human health in the United States. Personal protection measures, including use of chemical repellents, are recommended by the Centers for Disease Control and Prevention (CDC) to reduce the risk of tick bite and transmission of tick-borne pathogens that cause Lyme disease and other human disease vectored by ticks. This study evaluated the repellency and toxicity of eight novel chemical compounds of botanical origin against those two tick species using a vertical paper bioassay technique. Two compounds were found to be more effective than DEET, the standard repellent compound in most repellent products. EthoVision test system was used to further investigate the behavioral responses of ticks to the new compounds in comparison to DEET. The study resulted in a potential lead compound that may be of value for further consideration in product development and also a better understanding of the mode of action of those new repellent compounds.