Borrelia burgdorferi (Spirochaetales: Spirochaetaceae) Infection Prevalence and Host Associations of Ticks Found on Peromyscus spp. in Maryland.

Lyme disease, caused by Borrelia burgdorferi sensu stricto and most commonly transmitted by Ixodes scapularis Say (Ixodida: Ixodidae), is the most common tick-borne disease in Maryland. Because B. burgdorferi s.s. is maintained in enzootic cycles among wild mice (Peromyscus spp) and Ixodes spp ticks, differing patterns of parasitism of ticks on mice could impact the infection prevalence with B. burgdorferi. We determined the infection prevalence of Peromyscus spp as well as questing and partially engorged nymphal ticks collected at six sites on private land in five counties in Maryland from May to August 2020. Questing nymph infection prevalence (NIP) was 14%. We trapped 1258 mice and collected 554 ticks and 413 ear tissue samples. The prevalence of infested Peromyscus spp varied based on host age and sex, with older and male mice more likely to be infested. We detected a significant difference amongst the proportion of attached Ixodes and the location of trapping. Similarly, the prevalence of B. burgdorferi infected Peromyscus spp mice varied between locations (average mouse infection prevalence was 40%), with the highest prevalence in locations where Ixodes were the most commonly found ticks. The B. burgdorferi infection prevalence in partially engorged I. scapularis nymphs retrieved from Peromyscus spp was ~36% which lends further support to the host infection prevalence. Local differences in distribution of infected vectors and reservoirs are important factors to consider when planning interventions to reduce Lyme disease risk.

Optimal Collection Methods for Asian Longhorned Ticks (Ixodida: Ixodidae) in the Northeast United States.

The Asian longhorned tick, Haemaphysalis longicornis Neumann, is an invasive species in the United States. Since its earliest recorded presence in West Virginia in 2010, H. longicornis has been reported from 15 states. While its public health significance in the United States is unclear, globally it transmits pathogens that infect livestock and humans, causing economic losses and substantial morbidity. Management and control of H. longicornis requires knowledge of its biology, ecology, and distribution. Here, we address the need for effective collection methods for host-seeking H. longicornis as an important step for accurately assessing tick abundance and potential disease risk. The number of H. longicornis collected were compared across three collection methods (dragging, sweeping, CO2 traps) and three tick check distances (5 m, 10 m, and 20 m) were compared for dragging and sweeping. Field collections were conducted from June through August 2019 in Westchester County, New York, and ticks were grouped by life stage to assess collection method efficiency. Results indicated that implementing shorter (5 m) tick check distance was ideal for adult and nymphal collections. The dragging method proved better than sweeping for adult collections; however, there was no significant difference between the methods for nymphal collections, at any tick check distance evaluated. CO2 traps attracted H. longicornis, but additional research is necessary to devise an effective tick retaining method before the traps can be implemented in the field. The results are presented to inform and support H. longicornis surveillance and control programs across the nation.