Lyme borreliosis, caused by the spirochete Borrelia burgdorferi, is the most common tick-borne disease in the United States. The primary reservoir of this pathogen is the white-footed mouse, Peromyscus leucopus. While less common, cases occur every year outside of the range of P. leucopus, including in the southeastern United States. The relatively low number of cases in this region have resulted in little research focus on potential reservoirs of the causative agent. The few studies that have focused on B. burgdorferi in Florida have focused on B. burgdorferi sensu lato and have identified low infection rates in rodents throughout the state with the exception of the extreme northeastern portion of the state. One exception is a study that identified few isolates of B burgdorferi sensu stricto in Peromyscus gossypinus, the sister taxon of P. leucopus. Our study sought to identify the prevalence of B. burgdorferi genospecies in rodent hosts in central Florida. Rodents were live trapped and tissue samples were collected at Lake Woodruff National Wildlife Refuge during the summer and fall of 2019. Tissue samples were screened for B. burgdorferi via nested PCR of both the OspB and FlaB loci and results were verified, and identified to genospecies via DNA sequencing.
Results/Conclusions
Four rodent species were sampled during the course of this study: Neotoma floridana (n=32), Ochrotomys nuttalli (n=3), Peromyscus gossypinus (n=24), and Sigmodon hispidus (n=22). Overall, 29.63% of rodents sampled were positive for B. burgdorferi sensu lato. There was a significant effect of species on the likelihood of infection, with N. floridana harboring significantly more infected individuals (p=0.0391). Ochrotomys nuttalli exhibited no evidence of infection. This may be linked to relatively low abundance of this species in central Florida, but is also likely tied to a small size. A total of four S. hispidus (18.18%) were infected, but all samples were Borrelia bissetti (98.4-99.18% sequence similarity). Both P. gossypinus (25%) and N. floridana (43.75%) were infected with B. burgdorferi sensu stricto and no other genospecies. While additional research is needed, both P. gossypinus and N. floridana represent possible reservoirs of B. burgdorferi sensu stricto in central Florida. These data support the results of Clark 2004 and Rudenko et al. 2013 which identified B. burgdorferi sensu stricto in these rodent species. This study is the first to identify N. floridana as a possible reservoir of B. burgdorferi sensu stricto in Florida.