Evidence of rickettsiae in Danish patients tested for Lyme neuroborreliosis: a retrospective study of archival samples

Abstract

BackgroundWith a prevalence of 4.7–13% in Danish Ixodes ricinus ticks, Rickettsia helvetica is one of the most frequently detected tick-borne organisms in Denmark. Most reports of human exposure have described asymptomatic seroconversion or a mild, self-limiting flu-like illness but it has also been implicated as a cause of subacute lymphocytic meningitis. Because Borrelia burgdorferi sensu lato (Bbsl) and R. helvetica are both found in the same tick species, potential co-transmission is a possibility. We examined 1) the seroprevalence of anti-rickettsia antibodies in patients investigated for Lyme neuroborreliosis (LNB), and 2) the cerebrospinal fluid (CSF) and sera of same patients for the presence of Rickettsia DNA.MethodsNinety-nine sera and 87 CSF samples from patients with intrathecal synthesis of anti-Borrelia antibodies and 101 sera and 103 CSF samples from patients with no detectable intrathecal synthesis were retrospectively examined for this study. Sera were analyzed for antibodies against spotted fever group (SFG) rickettsiae and both the CSF and sera were tested for Rickettsia DNA using a genus-specific real-time PCR.ResultsOf the patients tested for LNB, 32% (64/200) had IgG antibodies against SFG rickettsiae. Among patients with confirmed intrathecal synthesis of Borrelia-specific antibodies, 38% (38/99) exhibited IgG antibodies. None of these values were statistically significant when compared with sera from healthy blood donors (p = 0.7 and 0.19). Rickettsia DNA was found in the CSF of 4% (8/190) of patients.ConclusionNo statistically significant difference was found in the seroprevalence of anti-rickettsia antibodies in patients tested for LNB and healthy blood donors, indicative of a low rate of exposure in this group of patients. Eight patients showed evidence of Rickettsia DNA in the CSF, five of whom had LNB. However, cycle threshold (Ct) values were high, indicating low concentrations of DNA, and no apparent alteration in the clinical manifestations of LNB were noted in the medical records of these patients.

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

“…Both B. miyamotoi and R. helvetica have been found to be associated with (other) neurological disorders in previous studies, but not with facial paralysis as in this study [ 8 , 17 , 18 ]. Facial paralysis is a well-known clinical sign of Lyme neuroborreliosis and sometimes also TBE [ 19 – 23 ], but has not been associated with other TBPs.…”

Are other tick-borne infections overlooked in patients investigated for Lyme neuroborreliosis? A large retrospective study from South-eastern Sweden

“…and serological methods for SFG rickettsiae, eight patients were found to be positive for Rickettsia spp. by PCR in the CSF, and most of them had symptoms and laboratory findings characteristic of LNB (Ocias et al, 2018). Rickettsia spp.…”

“…Several European studies, including those from Sweden (Bjöersdorff et al, 1999;Lindblom et al, 2013;Lindblom et al, 2016;Wass et al, 2018), have reported serological evidence of co-infections with different tick-borne pathogens in humans (Dunaj et al, 2018;Jahfari et al, 2016;Koetsveld et al, 2016;Moniuszko et al, 2014;Ocias et al, 2018;Panczuk et al, 2016). However, few of these studies have used molecular detection methods and the primary focus has not been on CNS infection.…”

A tick bite patient with fever and meningitis co-infected with Rickettsia raoultii and Tacheng tick virus 1: a case report

“…Previously, SFGR species were reported in co-infections with Borreli burgdorferi , Anaplasma phagocytophilum , Orientia tsutsugamushi and herpes simplex virus 2 [ 13 – 16 ]. In this study, we reported for the first time a tick bite patient co-infected with R .…”