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

Abstract

Questing ticks were surveyed by dragging in forested habitats within the Lehigh Valley region of eastern Pennsylvania for four consecutive summers (2015–2018). A high level of inter-annual variation was found in the density of blacklegged tick nymphs, Ixodes scapularis Say, with a high density of host-seeking nymphs (DON) in summer 2015 and 2017 and a relatively low DON in summer 2016 and 2018. Very few American dog ticks (Dermacentor variabilis Say) and Ixodes cookei Packard were collected. Lone star ticks (Amblyomma americanum L.) and longhorned ticks (Haemaphysalis longicornis Neumann) were not represented among the 6,398 ticks collected. For tick-borne pathogen surveillance, DNA samples from 1,721 I. scapularis nymphs were prepared from specimens collected in summers 2015–2017 and screened using qPCR, high resolution melting analysis, and DNA sequencing when necessary. The overall 3-yr nymphal infection prevalence of Borrelia burgdorferi was 24.8%, Borrelia miyamotoi was 0.3%, Anaplasma phagocytophilum variant-ha was 0.8%, and Babesia microti was 2.8%. Prevalence of coinfection with B. burgdorferi and B. microti as well as B. burgdorferi and A. phagocytophilum variant-ha were significantly higher than would be expected by independent infection. B. burgdorferi nymphal infection prevalence is similar to what other studies have found in the Hudson Valley region of New York, but levels of B. microti and A. phagocytophilum variant-ha nymphal infection prevalence are relatively lower. This study reinforces the urgent need for continued tick and pathogen surveillance in the Lehigh Valley region.

Global Distribution of Babesia Species in Questing Ticks: A Systematic Review and Meta-Analysis Based on Published Literature

“…The PPE of Babesia spp. in this tick was low at 3.60%, comparable to the prevalence reported from other individual studies [ 118 , 120 ]. Higher prevalence has been reported in other parts of America [ 113 , 117 ].…”

Sharing the Ride: Ixodes scapularis Symbionts and Their Interactions

“…No direct mechanistic interactions have been experimentally defined among the microbiota of I. scapularis, but several studies have detected correlations between various organisms. The likelihood of I. scapularis being coinfected with both B. microti and B. burgdorferi was found to be higher than expected based on single infection rates (Dunn et al, 2014;Hersh et al, 2014;Edwards et al, 2019). This co-occurrence rate may potentially be explained by the existence of a host competent for both microbes, allowing acquisition of B. microti and B. burgdorferi in a single bloodmeal.…”

Protozoan Parasite Babesia microti Subverts Adaptive Immunity and Enhances Lyme Disease Severity

“…Ixodes species tick populations have been increasing in the endemic regions and beyond and these vectors can transmit both B. burgdorferi and B. microti (Piesman et al, 1986; Jaenson et al, 2012; Lommano et al, 2012; Rizzoli et al, 2014; Johnson et al, 2017, 2018; Hahn et al, 2018; Piedmonte et al, 2018). The rise in incidence of B. microti and B. burgdorferi co-infections in humans appears to be driven primarily by increased co-infection of their common vector, ticks of the Ixodes species, which are capable of transmitting both pathogens simultaneously (Schulze et al, 2013; Dunn et al, 2014; Hersh et al, 2014; Knapp and Rice, 2015; Diuk-Wasser et al, 2016; Moutailler et al, 2016; Edwards et al, 2019). Although overall tick-borne co-infection rates are not yet documented in the United States, incidence of Lyme spirochetes and B. microti co-infections were as high as 40% in studies conducted with patient samples in two states in the Eastern United States, New Jersey and Connecticut (Diuk-Wasser et al, 2016; Primus et al, 2018).…”