Neoehrlichia mikurensis-An emerging opportunistic tick-borne infection in immunosuppressed patients.

BACKGROUND: Neoehrlichia mikurensis (N. mikurensis) is a newly discovered tick-borne pathogen that can inflict life-threatening illness in immunocompromised patients. N. mikurensis infection is only detectable by polymerase chain reaction (PCR)-based methodologies. We describe three distinct clinical manifestations of N. mikurensis infection (neoehrlichiosis) in Danish patients receiving B-lymphocyte-depleting therapy, rituximab, for underlying hematological, rheumatological, or neurological disorders. All three patients went through a protracted pre-diagnostic period. METHODS: N. mikurensis DNA was detected and confirmed using two methods. Blood was tested by specific real-time PCR targeting the groEL gene and by 16S and 18S profiling followed by sequencing. Bone marrow was analyzed by 16S and 18S profiling. RESULTS: N. mikurensis was detected in blood samples in all three cases and in bone marrow from one of the three. The severity of the symptoms ranged from prolonged fever lasting more than 6 months to life-threatening hyperinflammation in the form of hemophagocytic lymphohistiocytosis (HLH). Interestingly, all patients presented with splenomegaly and two with hepatomegaly. After starting doxycycline therapy, symptoms were relieved within a few days, and biochemistry and organomegaly quickly normalized. CONCLUSION: We present three Danish patients recognized by the same clinician over a period of 6 months, strongly suggesting that many cases are going unrecognized. Second, we describe the first case of N. mikurensis-induced HLH and emphasize the potential severity of undetected neoehrlichiosis.

Antibiotic therapy of neuroborreliosis: A survey among infectious disease specialists and neurologists in Norway, Sweden, and Denmark.

INTRODUCTION: Neuroborreliosis (NB) is a prevalent tick-borne neuroinfection in Europe. To delineate current practice in antimicrobial management of adults with NB and to prioritize future trials needed to optimize treatment recommendations, a questionnaire-based survey was performed. METHODS: A self-administered Internet-based survey of NB treatment practices among specialists in infectious diseases and neurology based in Norway, Sweden, and Denmark was carried out between October 2021 and February 2022. The participants were also asked to prioritize four pre-defined research questions for randomized controlled trials (RCTs) on therapy for NB. RESULTS: In total, 290 physicians (45% female) from Norway (30%), Sweden (40%), and Denmark (30%) participated in the survey. Of the responders, 230 (79%) were infectious disease specialists and 56 (19%) were neurologists. The preferred antibiotic treatment for patients with early NB was oral doxycycline (n = 225, 78%). Intravenous (IV) penicillin, ceftriaxone, or cefotaxime for the full treatment course was favored by 12%. A preferred treatment duration of 10-14 days for patients with NB was reported by 245 respondents (85%), most common among participants from Sweden (97%). A total of 170 (59%) responders reported having local hospital guidelines on the treatment of NB, most often with recommendation of oral doxycycline (92%) for 10-14 days (90%) as first line treatment. The prioritization score for future RCTs was highest for adjunctive prednisone therapy in NB patients with facial palsy (median 5; IQR 4-6) and for placebo versus repeated antibiotics in patients with persistent symptoms after completed antibiotic therapy for NB (median 5, IQR 3-6). CONCLUSION: In Sweden, all respondents preferred treating NB with oral doxycycline for 10-14 days, whereas 5% in Norway and 19% in Denmark still treat NB with IV antibiotics for the entire treatment course. RCTs to define the role of adjunctive prednisolone in NB patients with facial palsy and repeated antibiotics in patients with persistent symptoms are prioritized for future research.

Neurofilament Light in Cerebrospinal Fluid is Associated With Disease Staging in European Lyme Neuroborreliosis.

Background: Drivers of differences in disease presentation and symptom duration in Lyme neuroborreliosis (LNB) are currently unknown. Objectives: We hypothesized that neurofilament light (NfL) in cerebrospinal fluid (CSF) would predict disease location and sequelae in a historic LNB cohort. Design: Using a cross-sectional design and archived CSF samples from 185 patients diagnosed with LNB, we evaluated the content of NfL in the total cohort and in a subgroup of 84 patients with available clinical and paraclinical information. Methods: Individuals were categorized according to disease location: a. Central nervous system (CNS) with stroke (N=3), b. CNS without stroke (N=11), c. Peripheral nervous system (PNS) with cranial nerve palsy (CNP) (N=40) d. PNS without CNP (N=30). Patients with hospital follow-up more than 6 months after completed antibiotic therapy were categorized as having LNB associated sequelae (N=15). Results: At diagnosis concentration of NfL exceeded the upper reference level in 60% (105/185), especially among individuals above 30 years. Age-adjusted NfL was not found to be associated with symptom duration. Age-adjusted NfL was significantly higher among individuals with CNS involvement. Category a. (stroke) had significantly higher NfL concentrations in CSF compared to all other categories, category b. (CNS involvement without stroke) had significantly higher values compared to the categories of PNS involvement. We found no significant difference between the categories with PNS involvement (with or without CNP). Significantly higher NfL was found among patients with follow-up in hospital setting. Conclusion: Comparison of NfL concentrations between the 4 groups of LNB disease manifestations based on clinical information revealed a hierarchy of neuron damage according to disease location and suggested evolving mechanisms with accelerated injury especially when disease is complicated by stroke. Higher values of NfL among patients with need of follow-up in hospital setting suggest NfL could be useful to identify rehabilitative needs.

Classification of patients referred under suspicion of tick-borne diseases, Copenhagen, Denmark.

To provide better care for patients suspected of having a tick-transmitted infection, the Clinic for Tick-borne Diseases at Rigshospitalet, Copenhagen, Denmark was established. The aim of this prospective cohort study was to evaluate diagnostic outcome and to characterize demographics and clinical presentations of patients referred between the 1st of September 2017 to 31st of August 2019. A diagnosis of Lyme borreliosis was based on medical history, symptoms, serology and cerebrospinal fluid analysis. The patients were classified as definite Lyme borreliosis, possible Lyme borreliosis or post-treatment Lyme disease syndrome. Antibiotic treatment of Lyme borreliosis manifestations was initiated in accordance with the national guidelines. Patients not fulfilling the criteria of Lyme borreliosis were further investigated and discussed with an interdisciplinary team consisting of specialists from relevant specialties, according to individual clinical presentation and symptoms. Clinical information and demographics were registered and managed in a database. A total of 215 patients were included in the study period. Median age was 51 years (range 17-83 years), and 56 % were female. Definite Lyme borreliosis was diagnosed in 45 patients, of which 20 patients had erythema migrans, 14 patients had definite Lyme neuroborreliosis, six had acrodermatitis chronica atrophicans, four had multiple erythema migrans and one had Lyme carditis. Furthermore, 12 patients were classified as possible Lyme borreliosis and 12 patients as post-treatment Lyme disease syndrome. A total of 146 patients (68 %) did not fulfil the diagnostic criteria of Lyme borreliosis. Half of these patients (73 patients, 34 %) were diagnosed with an alternative diagnosis including inflammatory diseases, cancer diseases and two patients with a tick-associated disease other than Lyme borreliosis. A total of 73 patients (34 %) were discharged without sign of somatic disease. Lyme borreliosis patients had a shorter duration of symptoms prior to the first hospital encounter compared to patients discharged without a specific diagnosis (p<0.001). When comparing symptoms at presentation, patients discharged without a specific diagnosis suffered more often from general fatigue and cognitive dysfunction. In conclusion, 66 % of all referred patients were given a specific diagnosis after ended outpatient course. A total of 32 % was diagnosed with either definite Lyme borreliosis, possible Lyme borreliosis or post-treatment Lyme disease syndrome; 34 % was diagnosed with a non-tick-associated diagnosis. Our findings underscore the complexity in diagnosing Lyme borreliosis and the importance of ruling out other diseases through careful examination.