Self-reported symptoms and health complaints associated with exposure to Ixodes ricinus-borne pathogens

Abstract

Background The impact of infections with tick-borne pathogens (TBPs) other than Borrelia burgdorferi (s.l.) and tick-borne encephalitis virus (TBEV) on public health in Europe remains unclear. Our goal is to evaluate whether the presence of these TBPs in ticks can be associated with self-reported health complaints. Methods We enrolled individuals who were bitten by I. ricinus between 2012 and 2015 and collected their relevant demographic and clinical information using a self-administered online questionnaire. A total of 4163 I. ricinus ticks sent by the participants were subject to molecular analyses for detection of specific TBPs. Associations between the presence of TBPs in ticks and self-reported complaints and symptoms were evaluated by means of a stepwise approach using a generalized linear model (GLM). Results Of 17 self-reported complaints and symptoms significant in the univariate analyses, 3 had a highly significant association (P < 0.01) with at least one TBP in the multivariate analysis. Self-reported Lyme borreliosis was significantly associated (P < 0.001) with B. burgdorferi (s.l.) infection. Facial paralysis was associated (P < 0.01) with infection with B. miyamotoi, N. mikurensis and R. helvetica. Finally, a significant association (P < 0.001) was found between nocturnal sweating and A. phagocytophilum. Conclusions We found associations between the presence of TBPs in ticks feeding on humans and self-reported symptoms. Due to the subjective nature of such reports and the fact that infection was determined in the ticks and not in the patient samples, further prospective studies utilizing diagnostic modalities should be performed before any clinical outcome can be causally linked to infection with TBPs. Graphical Abstract

Assembly and Comparison of Ca. Neoehrlichia mikurensis Genomes

“…One of the major obstacles to investigating how often and under what conditions Ca. N. mikurensis causes an infectious disease in humans, is its unequivocal detection in larger cohorts of patients with noncharacteristic disease symptoms [11,12] or in persons with a (recent) tick bite [13][14][15]. In other words, supportive laboratory diagnostics to detect and identify Ca.…”

Technical Evaluation of qPCR Multiplex Assays for the Detection of Ixodes ricinus-Borne Pathogens

“…This endeavour was performed within the limits of dealing with microorganisms for which confirmed patient materials are scarce or non-existent [10,19], a hurdle that was partially overcome by using synthetic controls for the technical evaluation of the assays. Using the multiplex qPCRs, as little as 10 to 79 copies per PCR reaction could be detected for each of the targeted TBPs, which is a 10 to 10,000 times higher sensitivity compared to that of the multiplex PCR for the detection of nine TBPs evaluated in a similar manner by Buchan et al [31].…”

“…The CT values of EDTA 1 were 33.91 and 37. 19, respectively, and the CT values of EDTA 4 were 20.89 and 22.26, respectively. No DNA was detected in the remaining EDTA samples 2, 3 and 5 at both laboratories.…”

“…For some of these TBPs, the pathogenicity remains questionable, and only few well described cases exist [9]. Over the last decades, only two autochthonous anaplasmosis cases, two B. miyamotoi cases, but no cases of neoehrlichiosis or human babesiosis have been reported in the Netherlands [19]. Lack of awareness, case definitions, laboratory diagnostics, as well as a noncharacteristic clinical presentation are among the reasons why these other TBDs often go undiagnosed [12,20].…”

“…were evaluated. These evaluated assays have previously been used in singleplex in various studies in the Netherlands where the prevalence of TBPs in both questing and fed I. ricinus [17,19,23], animal hosts [17,23], human populations at risk as well as the general population [9,16,24] has been assessed. The aim of this study was to perform a technical validation of these qPCRs in order to estimate their potential in human diagnostics.…”