A rodent and tick bait for controlling white-footed mice (Peromyscus leucopus) and blacklegged ticks (Ixodes scapularis), the respective pathogen host and vector of the Lyme disease spirochetes.

Abstract

A promising alternative approach to conventional vector and rodent control practices is the use of a bait containing a rodenticide and acaricide in controlling vectors and pathogen reservoirs concurrently. In the United States, Lyme disease continues to be the most prevalent vector-borne disease with approximately 500,000 Lyme disease cases estimated each year. Previous research has demonstrated the usefulness of a low dose fipronil bait in controlling Ixodes scapularis larvae feeding on white-footed mice. However, considering white-footed mice can be an unwanted species because of their association with tick-borne disease and hantaviruses, a combination rodent and tick bait (RTB) might provide a useful alternative to encourage additional community participation in integrated tick management (ITM) efforts. The purpose of this research was to evaluate the use of RTB (0.025 % warfarin, 0.005 % fipronil) in controlling white-footed mice and I. scapularis larvae. Studies were designed in part based on Environmental Protection Agency (EPA) guidelines. A laboratory choice test was conducted to evaluate the use of RTB in controlling white-footed mice over 15-day exposure when they were exposed to an alternative diet. Mice were observed every day for mortality and signs of warfarin toxicity. A simulated field test was conducted to evaluate the use of RTB, presented in the presence of an alternative diet, in controlling I. scapularis parasitizing white-footed mice over 4-day exposure. Mice were fitted with capsules and manually infested with I. scapularis larvae. The inside of each capsule was observed to evaluate tick attachment. Replete larvae detaching from each mouse were collected. Blood was collected from all treatment group mice via cardiac puncture to determine the fipronil sulfone concentration in plasma for each animal. Results indicated that RTB would be adequately consumed in the presence of an alternative diet under laboratory and simulated field conditions. Treatment with RTB resulted in 100 % mortality of white-footed mice during 15-day exposure and prevented 100 % larvae from feeding to repletion during 4-day exposure. All mice succumbing to RTB showed signs of warfarin toxicity. All mice parasitized with ticks that were exposed to RTB had fipronil sulfone detectable in plasma, with even the lowest concentration detected (8.1 parts per billion) controlling 100 % parasitizing I. scapularis larvae. The results suggest that RTB could be a useful means of rodent and tick control for use in ITM programs.