Use of LYMESIM 2.0 to assess the potential for single and integrated management methods to control blacklegged ticks (Ixodes scapularis; Acari: Ixodidae) and transmission of Lyme disease spirochetes

Annual Lyme disease cases continue to rise in the U.S. making it the most commonly reported vector-borne illness in the country. The complex relationship between the bacteria that causes the disease (Borrelia burgdorferi or Bb) and the primary vector (Ixodes scapularis; blacklegged tick) is complicated by the multitude of vertebrate hosts and varying environmental factors. LYMESIM 2.0, a mechanistic model, has been shown to be effective in understanding and predicting tick population and pathogen transmission dynamics based on these many factors. However, this current version of LYMESIM has not been used to explore the effectiveness of different tick control methods. Thus, the purpose of the current study was to examine the effectiveness of three commonly used tick control treatments: habitat-targeted acaricide (spraying), small mammal targeted acaricide (bait boxes), and white-tailed deer targeted acaricide (4-poster). The model was used to evaluate the most effective combination of controls and time window of application. Additionally, simulations were run to evaluate this combination applied at various durations, e.g., consecutive years vs every other year, and various effectiveness levels. It was determined that spraying in tandem with bait boxes and 4-posters, would be the best method of control as this combination of treatments results in \u3e 80% suppression in the density of blacklegged tick nymphs (DON). Furthermore, the best time to apply those treatments was between weeks 1-16 (e.g., January through mid-April) and 37-48 (e.g., mid-September to early December). Additionally, application of treatment every year or every other year at a minimum effectiveness of 25% is required to achieve 80% DON suppression and no increases in blacklegged ticks beyond their pre-treatment abundance in the years after treatments are stopped. With these conclusions, we can recommend the best method of blacklegged tick population control that is both time and cost-effective