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

Abstract

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.

Passive Surveillance of SARS-CoV-2 in Adult Blacklegged Ticks (Ixodes scapularis) from Northeast Pennsylvania

“…This includes testing for the Omicron variant, which appeared in the United States in December 2021 [ 27 ]. In order for a blacklegged tick to become a vector, the tick must acquire the pathogen from a reservoir host, such as white-tailed deer, in the Spring and maintain that pathogen throughout its two-year life cycle [ 1 ]. If future studies demonstrate that I. scapularis do carry COVID-19, then additional research should be conducted in order to determine whether the ticks are contracting SARS-CoV-2 from white-tailed deer who are positive for COVID-19 or if the ticks are infecting the deer with COVID-19.…”

“…The ladder used in these gels ran from 100-1000 base pairs, using fragments of 100 base pairs. 397 39.704 39.691 444 35.024 38.507 1 The Cq cut-off for the N1 assay was 35, and the Cq cut-off for the N2 assay was 37. 2 PU BT = up below the threshold (began to amplify during PCR but did not cross the threshold).…”

“…Table 5. Tick IDs and their associated melt curves in secondary testing with S-COV primer SYBR green) 1 . Gel electrophoresis results for these three samples showed experimental amp sizes that differed from the size of the targeted amplicon, which was approximatel base pairs [25].…”

“…Ticks are known vectors for many pathogens that cause disease in humans, including Lyme disease, human babesiosis, and human granulocytic anaplasmosis [ 1 ]. Cases of tick-borne diseases (TBDs) are increasing due to the northward and westward geographic range expansion of ticks in the United States.…”

Emerging tickborne viruses vectored by Amblyomma americanum (Ixodida: Ixodidae): Heartland and Bourbon viruses

“…Co-infections of two or more human pathogens found in a single tick have been reported for A. americanum and especially I. scapularis (Schulze et al 2005, 2013, Tokarz et al 2010, Aliota et al 2014, Hersh et al 2014, Killmaster et al 2014, Prusinski et al 2014, Cross et al 2018, Sanchez-Vicente et al 2019, Cutler et al 2021, Milholland et al 2021, Zembsch et al 2021, Hart et al 2022, Schwartz et al 2022). Elucidating the effects of co-infection of diverse pathogens (viral, bacterial, parasitic) within A. americanum and other species should be included in future studies.…”