| 1. |
- Grankvist, Anna, et al.
(författare)
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Infections with Candidatus Neoehrlichia mikurensis and Cytokine Responses in 2 Persons Bitten by Ticks, Sweden
- 2015
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Ingår i: Emerging Infectious Diseases. - : Centers for Disease Control and Prevention (CDC). - 1080-6040 .- 1080-6059. ; 21:8, s. 1462-1465
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Tidskriftsartikel (refereegranskat)abstract
- The prevalence of Candidatus Neoehrlichia mikurensis infection was determined in 102 persons bitten by ticks in Sweden. Two infected women had erythematous rashes; 1 was co-infected with a Borrelia sp., and the other showed seroconversion for Anaplasma phagocytophilum. Both patients had increased levels of Neoehrlichia DNA and serum cytokines for several months.
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| 2. |
- Labbé Sandelin, Lisa, 1977-, et al.
(författare)
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Detection of Neoehrlichia mikurensis DNA in blood donors in southeastern Sweden
- 2022
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Ingår i: Infectious Diseases. - : Taylor & Francis Group. - 2374-4235 .- 2374-4243. ; 54:10, s. 748-759
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Tidskriftsartikel (refereegranskat)abstract
- Background The tick-borne bacterium Neoehrlichia mikurensis can cause persistent asymptomatic bloodstream infections, but transfusion-mediated transmission has not been reported. This study aimed to investigate the prevalence of N. mikurensis in blood donors, and recipients of blood components from N. mikurensis-positive donors were traced.Methods In 2019 and 2021, 1007 blood donors were recruited. Participants completed a questionnaire and additional blood samples were collected during blood donation. Detection of N. mikurensis was performed by PCR followed by sequencing. Positive donors were interviewed and retested. Look-back was performed on positive donations and on all subsequent donations.Results N. mikurensis was detected in 7/1006 (0.7%) donors. A total of 380/1005 (38%) donors reported at least one noticed tick bite during the current season. The questionnaire could not detect any differences between negative and positive N. mikurensis-donors. Two of the positive donors were still positive on days 318 and 131 after the index donation, respectively. One donor with persistent N. mikurensis in blood experienced slight fatigue. All other had no symptoms attributable to neoehrlichiosis. Look-back included ten donations and 20 blood components. Eight components were discarded, and 12 recipients of N. mikurensis-positive donations were identified. PCR was negative in seven recipients. Five recipients had died, but their medical records gave no evidence for neoehrlichiosis.Conclusions Although N. mikurensis was found in 0.7% of blood donors, transfusion-mediated infection was not detected, despite several recipients being at high risk for severe neoehrlichiosis. The results warrant further studies as well as raised clinical awareness.
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| 3. |
- Labbé Sandelin, Lisa, 1977-
(författare)
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Neoehrlichia mikurensis in Sweden : An emerging tick-borne human pathogen
- 2022
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Neoehrlichia mikurensis is an emerging tick-borne human pathogen, causing neoehrlichiosis in immunosuppressed and immunocompetent individuals. It targets the vascular endothelium, leading to thromboembolic and vascular events, but can also pass without symptoms. As symptoms easily are misinterpreted, immunosuppressive treatment or chemotherapy is often incorrectly initiated. Diagnostic delay can be considerable.The overall aim of this thesis was to gain a better understanding on N. mikurensis in Sweden, focusing on human infections and public health aspects. The prevalence of N. mikurensis in different populations was examined. The symptomatology of neoehrlichiosis and the risk of transfusion-mediated transmission was studied. N. mikurensis was observed in low prevalences in ticks collected from migratory birds, in tick-bitten individuals, in patients with persistent symptoms attributed to presumed tick-bite exposure, and in blood donors. Fourteen N. mikurensis-positive individuals were identified. The majority were immunocompetent and asymptomatic. Both spontaneous clearance and persistence was observed. Two of 102 tick-bitten individuals were N. mikurensis-positive. Both presented with erythema migrans, but borreliosis was a more probable cause in both. The findings do not support a change in practice regarding first-line treatment of erythema migrans, but further studies are warranted.Persistence of N. mikurensis in blood raises questions regarding the possibility of transmission by transfusion and the risk of activating the infection if immune status is altered. N. mikurensis was identified in seven out of 1 006 blood donors. Look-back and tracing identified 12 recipients who were transfused with blood components from N. mikurensis-positive donors. Several recipients had multiple risk factors for severe neoehrlichiosis, but transfusion-transmitted neoehrlichiosis was not detected. Nevertheless, the possibility that N. mikurensis can be transmitted by transfusion cannot be excluded.Isolates from birds and blood donors were identical to previously reported Swedish human isolates. Migrating birds can act as dispersal vectors of N. mikurensis, but their role as transmission hosts is still unclear.The disease burden and public health impact of neoehrlichiosis is probably small, but information is lacking in several areas. Suspicion of neoehrlichiosis is warranted in immunocompromised and/or splenectomised patients with persistent fever, with or without thromboembolic and vascular events. Furthermore, neoehrlichiosis should be included in the differential diagnosis of anaplasmosis. Besides raised awareness, a possible mandatory notification is proposed as well as a comprehensive surveillance system for transfusion-transmitted infections. One of the priority issues is the possible need for screening of patients living in N. mikurensis-endemic areas before and during immunosuppressive treatment.
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| 4. |
- Nilsson, Kenneth, Docent, 1953-, et al.
(författare)
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A comprehensive clinical and laboratory evaluation of 224 patients with persistent symptoms attributed to presumed tick-bite exposure
- 2021
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Ingår i: PLOS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 16:3
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Tidskriftsartikel (refereegranskat)abstract
- Background Persistent symptoms attributed to presumed tick-bite exposure constitute an unresolved medical controversy. We evaluated whether Swedish adults who met the criteria for post-treatment Lyme disease syndrome (PTLDS) exhibited characteristics distinguishable from adults who did not, but who displayed similar symptoms and disease course after suspected previous tick-bite infection (TBI). Methods and findings During 2015-2018, 255 patients-referred to the Centre for Vector-borne Infections, Uppsala University Hospital, Sweden with symptoms lasting longer than six months-were recruited. Of this group, 224 completed the study. Each patient was examined by an infectious disease specialist and, besides a full medical history, underwent a panel of blood and cerebrospinal fluid laboratory tests including hematological, biochemical, microbiological and immunological analyses, and the RAND-36 scale to measure quality of life. For analysis purposes, patients were divided into five subgroups, of which one represented PTLDS. According to serological results indicating TBI and documented/ reported objective signs of Lyme disease, 85 (38%) patients fulfilled the criteria for PTLDS and were compared with the other 139 (62%) serologically classified patients. In the PTLDS group, erythema chronicum migrans (ECM) was documented/reported in 86% of patients, previous neuroborreliosis in 15%, and acrodermatitis chronica atroficans (ACA) in 3.5%. However, there were no significant differences regarding symptoms, laboratory results or disease course between patients with PTLDS and those without laboratory evidence of Borrelia exposition. Most reported symptoms were fatigue-related (70%), musculoskeletal (79%), neurological (82%) and neurocognitive (57%). Tick bites were recalled by 74%. The RAND-36 score was significantly below that of the general Swedish population. Signs of immunological/inflammatory reactivity with myositis antibodies were detected in 20% of patients, fibrinogen levels were moderately increased in 21% and elevated rheumatoid factor in 6%. Conclusions The PTLDS group did not differ exclusively in any respect from the other subgroups, which either lacked previously documented/reported evidence of borreliosis or even lacked detectable serological signs of exposure to Lyme disease. The results suggest that symptoms often categorized as Chronic-Lyme-Disease (CLD) in the general debate, cannot be uniquely linked to Lyme disease. However, approximately 20% of the total group of patients showed signs of autoimmunity. Further studies are needed to elucidate the underlying causes and mechanisms of PTLDS and there is reason to consider a multifactorial approach.
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