Optimization of tissue sampling for Borrelia burgdorferi in white-footed mice (Peromyscus leucopus).

Peromyscus leucopus (the white-footed mouse) is a known reservoir of the Lyme disease spirochete Borrelia burgdorferi. Sampling of white-footed mice allows for year-round B. burgdorferi surveillance as well as opportunities to establish the diversity of the different variants in a geographic region. This study explores the prevalence of B. burgdorferi infections in the tissues of white-footed mice, investigates the correlations between B. burgdorferi infected tissues, and determines the optimum field methods for surveillance of B. burgdorferi in P. leucopus. A total of 90 mice and 573 tissues (spleen, liver, ear, tongue, tail, heart, and kidney) were screened via nested PCR for B. burgdorferi infections. A large number of infections were found in the 90 mice as well as multiple infections within individual mice. Infections in a single mouse tissue (spleen, liver, ear, tongue and tail) were predictive of concurrent infection in other tissues of the same mouse at a statistically significant level. Ear tissue accounted for 68.4% of detected infections, which increased to 78.9% of the infected mice with the inclusion of tail samples. The use of ear punch or tail snip samples (used individually or in tandem) have multiple advantages over current Lyme disease ecological studies and surveillance methodologies, including lower associated costs, minimization of delays, year-round B. burgdorferi testing opportunities, as well as longitudinal monitoring of B. burgdorferi in defined geographic regions. In the absence of an effective vaccine, personal prevention measures are currently the most effective way to reduce Lyme disease transmission to humans. Thus, the identification and monitoring of environmental reservoirs to inform at-risk populations remains a priority. The sampling methods proposed in this study provide a reasonable estimate of B. burgdorferi in white-footed mice in a timely and cost-effective manner.