Active surveillance was conducted by collecting questing ticks from vegetation through a 2-yr survey in Pike County, Pennsylvania. Over a thousand blacklegged ticks (Ixodes scapularis Say) and American dog ticks (Dermacentor variabilis Say) were collected. A single specimen of the following species was collected: lone star tick (Amblyomma americanum L.), rabbit tick (Haemaphysalis leporispalustris Packard), and an Asian longhorned tick (Haemaphysalis longicornis Neumann). This study represents the largest county-wide study in Pennsylvania, surveying 988 questing I. scapularis adult and nymphs. Molecular detection of five distinct tick-borne pathogens was screened through real-time PCR at a single tick resolution. Respectively, the overall 2-yr adult and nymph prevalence were highest with Borrelia burgdorferi (Spirochaetales: Spirochaetacceae) (45.99%, 18.94%), Anaplasma phagocytophilum (Rickettsiales: Anaplasmataceae) (12.29%, 7.95%) where the variant-ha (8.29%, 3.03%) was overall more prevalent than the variant-v1 (2.49%, 4.17%), Babesia microti (Piroplasmida: Babesiidae) (4.97%, 5.30%), Borrelia miyamotoi (Spirochaetales: Spirochaetaceae) (1.38%, 1.89%), and Powassan virus lineage II [POWV]/deer tick virus (DTV) (2.07%, 0.76%). Adult and nymph coinfection prevalence of B. burgdorferi and B. microti (3.03%, 4.97%) and adult coinfection of B. burgdorferi and A. phagocytophilum or A. phagocytophilum and B. microti were significantly higher than the independent infection rate expected naturally. This study highlights the urgency to conduct diverse surveillance studies with large sample sizes to better understand the human risk for tick-borne diseases within small geographical areas.

Winter ticks (Dermacentor albipictus) are an aggressive one-host tick that infest a wide-diversity of ungulates. Infestations can result in anemia, alopecia, emaciation, and death. Most notably, the winter tick has caused negative impacts to moose (Alces alces) populations in the northeast United States and Canada. Winter ticks have been identified on other cervid species, including deer (Odocoileus virginianus) and elk (Cervus canadensis), which generally results in low tick burdens and mild or no disease. Recently, however, a wild yearling bull elk in Pennsylvania was found dead as a result of severe winter tick infestation. To obtain baseline data on winter ticks in wild elk in Pennsylvania, we collected 1453 ticks from 190 hunter-harvested wild elk between 2017–2018. Of the 204 harvested elk, 94.3% (190/204) had ticks collected for this study and none of the sampled elk had evidence of winter-tick associated disease. The average tick burden was 7.7 ticks/elk and average winter tick load on all elk was 0.5. Results of this study indicate that winter ticks do infest wild elk in Pennsylvania. However, during the fall months, the tick burden is low and rarely associated with lesions. These data herein serve as a baseline to monitor winter tick populations over time.

In 2017, a male elk (Cervus canadensis) was found dead in Pennsylvania, US. The elk was in poor nutritional condition and had alopecia and ulcerative dermatitis throughout the neck and dorsum region associated with severe Dermacentor albipictus infestations. Histologically, there was severe chronic-active dermatitis with hyperkeratosis and crust formation.