Borrelia miyamotoi infection rate in black-legged ticks (Ixodes scapularis) recovered from heads of hunter-harvested white-tailed deer (Odocoileus virginianus) in Pennsylvania: A public health perspective

Abstract

Studies reporting tick infection rates for Borrelia miyamotoi, a zoonotic arthropod-borne pathogen responsible for Borrelia miyamotoi disease, in the Commonwealth of Pennsylvania are limited. To ascertain a statewide infection rate of B. miyamotoi, ticks were collected from heads of 9,912 hunter-harvested white-tailed deer (Odocoileus virginianus) presented to six regional Pennsylvania Game Commission Chronic Wasting Disease sampling stations in early December of 2013, 2014, and 2015. Of the 2973 ticks recovered, 1990 (66.9%) were identified as adult Ixodes scapularis. The 1990 I. scapularis ticks were grouped into 409 pools containing one to six ticks and PCR-tested for the presence of B. miyamotoi. The pooled samples had a statewide maximum likelihood estimation tick infection rate of 7.64/1000 (95% CI, 4.46–12.29) for B. miyamotoi, confirming a state-wide presence, and supporting the need for an increased public health awareness for this emerging zoonotic arthropod-borne pathogen.

A 4-Yr Survey of the Range of Ticks and Tick-Borne Pathogens in the Lehigh Valley Region of Eastern Pennsylvania

“…Their state-wide estimate based on 1,990 ticks, was ~0.8% (95CI 0.4–1.2). Our B. miyamotoi nymphal prevalence may be lower than Farrone et al (2018) because their study only included adult ticks which would have taken two blood meals. B. miyamotoi infected nymphs may be rare in the Lehigh Valley region, but human–tick encounters are common.…”

“…This prevalence is not significantly different from Barbour et al (2009) who detected the pathogen in a single sample among 32 nymphs collected in nearby Reading, PA (3.1%; 95CI 0.3–13.7) and one in 100 nymphs collected near Harrisburg, in central PA (1.0%; 95CI 0.1–4.6). Most recently, Farone et al (2018) estimated a B. miyamotoi infection prevalence of 1.7% (95CI 0.6–3.7) in 304 pooled I. scapularis adults that were collected from deer hunted in a sector of northeastern PA that includes the Lehigh Valley region. Their state-wide estimate based on 1,990 ticks, was ~0.8% (95CI 0.4–1.2).…”

“…The noninformative (Jeffrey’s) prior results are presented here since the results for the nymphal infection prevalence estimates for each of the pathogens did not change significantly as the dispersion of the priors was increased for this prior, which indicates that the nymphal infection prevalence results presented here are driven by the data rather than the prior distribution. When reporting prevalence data from other published studies (i.e., Barbour et al 2009, Hersh et al 2014, Keesing et al 2014, Prusinsky et al 2014, Hutchinson et al 2015, Farone et al 2018), 95CI were calculated with the EpiTools package from Ausvet (2019) using the Jeffrey’s prior (Brown et al 2001).…”

Tick-Borne Pathogens in Questing Blacklegged Ticks (Acari: Ixodidae) From Pike County, Pennsylvania

“…Nymphal prevalence (1.89%, 95% CI: 0.62–4.36) was slightly higher than the adults infected with B. miyamotoi (1.38%, 95% CI: 0.66–2.53), however, not determined significantly through the GLM ( Table 5 ). The higher nymphal prevalence might be driven by the transovarial transmission observed in B. miyamotoi and I. scapularis ( Barbour et al 2009 , Dibernardo et al 2014 , Farone et al 2018 ). A recent PA statewide study found 0.33% (1/299) adults positive with B. miyamotoi , lower than adult prevalence in this study ( Livengood et al 2020 ).…”

“…In PA, the blacklegged tick has been associated with human bacterial pathogens, Borrelia burgdorferi , Anaplasma phagocytophilum , and Borrelia miyamotoi ; protozoal pathogens such as Babesia microti ; and viral pathogens such as Powassan virus ( Hersh et al 2014 , Hutchinson et al 2015 , Farone et al 2018 , Edwards et al 2019 ). Both the nymph and adult life stages of I. scapularis have been associated with human illness; however, the nymph life stage has primarily contributed to human Lyme disease (LD) infection in the eastern United States ( Eisen and Dolan 2016 ).…”