Septicemia caused by tick-borne bacterial pathogen Candidatus Neoehrlichia mikurensis.
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ABSTRACT:
SUBMITTER: Fehr JS
PROVIDER: S-EPMC3358111 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:BACKGROUND: 'Candidatus Neoehrlichia mikurensis' is a tick-borne bacteria implicated in human health. To date, 'Ca. Neoehrlichia mikurensis' has been described in different countries from Africa, Asia and Europe, but never in Spain. However, according to the epidemiological features of the main vector in Europe, Ixodes ricinus, its circulation in our country was suspected. METHODS: A total of 200 I. ricinus ticks collected in the North of Spain were analyzed. DNAs were extracted and used as templates for PCRs targeting fragment genes for Anaplasma/Ehrlichia detection. The amplified products were sequenced and analyzed. RESULTS: 'Ca. Neoehrlichia mikurensis' was amplified in two specimens. Furthermore, Anaplasma phagocytophilum was detected in 61 samples analyzed. CONCLUSIONS: The detection of 'Ca. Neoehrlichia mikurensis' in I. ricinus ticks from Spain indicates its circulation and the potential risk of contracting a human infection in this country.
| S-EPMC3912351 | biostudies-literature
Project description:The tick-borne bacterium "Candidatus Neoehrlichia mikurensis" has recently been recognized as a human pathogen. Together with Borrelia afzelii, it is one of the most common pathogens found in the tick Ixodes ricinus. Here, we compared the epidemiologies of "Ca. Neoehrlichia mikurensis" and B. afzelii by longitudinal sampling from May to September in one of their most abundant vertebrate hosts, the bank vole (Myodes glareolus), using real-time PCR for detection and quantification. The prevalences of "Ca. Neoehrlichia mikurensis" and B. afzelii were determined to be 19% (50/261) and 22% (56/261), respectively. The prevalence of "Ca. Neoehrlichia mikurensis" increased significantly during the sampling season. The clearance rate of "Ca. Neoehrlichia mikurensis" was significantly higher than that of B. afzelii. We found a high frequency of double infections; 46% of all samples infected with "Ca. Neoehrlichia mikurensis" also had a coinfection with B. afzelii. The frequency of coinfections was significantly higher than expected from the prevalence of each pathogen. The high level of coinfections can be caused by interactions between the pathogens or might reflect variation in general susceptibility among voles.
| S-EPMC3957614 | biostudies-literature
Project description:Tick-borne 'Neoehrlichia (N.) mikurensis' is the cause of neoehrlichiosis, an infectious vasculitis of humans. This strict intracellular pathogen is a member of the family Anaplasmataceae and has been unculturable until recently. The only available genetic data on this new pathogen are six partially sequenced housekeeping genes. The aim of this study was to advance the knowledge regarding 'N. mikurensis' genomic relatedness with other Anaplasmataceae members, intra-species genotypic variability and potential virulence factors explaining its tropism for vascular endothelium. Here, we present the de novo whole-genome sequences of three 'N. mikurensis' strains derived from Swedish patients diagnosed with neoehrlichiosis. The genomes were obtained by extraction of DNA from patient plasma, library preparation using 10× Chromium technology, and sequencing by Illumina Hiseq-4500. 'N. mikurensis' was found to have the next smallest genome of the Anaplasmataceae family (1.1 Mbp with 27% GC contents) consisting of 845 protein-coding genes, every third of which with unknown function. Comparative genomic analyses revealed that 'N. mikurensis' was more closely related to Ehrlichia chaffeensis than to Ehrlichia ruminantium, the opposite of what 16SrRNA sequence-based phylogenetic analyses determined. The genetic variability of the three whole-genome-sequenced 'N. mikurensis' strains was extremely low, between 0.14 and 0.22‰, a variation that was associated with geographic origin. No protein-coding genes exclusively shared by N. mikurensis and E. ruminantium were identified to explain their common tropism for vascular endothelium.
| S-EPMC8303192 | biostudies-literature
Project description:Neoehrlichia mikurensis is an intracellular bacterium transmitted in Europe and Asia by ticks of the Ixodes ricinus complex. Interest in this bacterium has increased since it was demonstrated to be responsible for febrile syndromes in patients. To date, most clinical cases have been reported in northern Europe, but case series have also been described in central Europe and China. Notably, thrombotic events occurred during the course of the disease. We investigated the presence of N. mikurensis in 10,885 I. ricinus nymphs in two regions of France (Alsace and Brittany) collected between 2013 and 2020 and in 934 patients suspected of human granulocytic anaplasmosis in Alsace, an endemic area for Lyme borreliosis, using a specific PCR assay. N. mikurensis was detected in 5.42% of the ticks from Alsace, whereas only one (0.03%) tick was found to be positive in Brittany. Spatiotemporal disparities were also noticed within the Alsace region over the four collection sites investigated, and a significant increase in the prevalence of nymphs carrying N. mikurensis was also observed in the last three years of collection. Four out of 934 screened patients were found to be positive for N. mikurensis. Two had malignancies, and the other two were apparently immunocompetent. Superficial thrombosis was noticed in one patient, and long-lasting bacteremia was noted in another patient. These four patients are the first clinical cases of neoehrlichiosis described in France. We suggest including N. mikurensis in the differential diagnosis of post-tick bite febrile syndromes to treat patients and prevent the occurrence of thrombotic complications.
| S-EPMC8425734 | biostudies-literature
Project description:To identify Candidatus Neoehrlichia mikurensis infection in northeastern China, we tested blood samples from 622 febrile patients. We identified in 7 infected patients and natural foci for this bacterium. Field surveys showed that 1.6% of ticks and 3.8% of rodents collected from residences of patients were also infected.
| S-EPMC3471638 | biostudies-literature
Project description:To further assess the geographic occurrence, possible vectors, and prevalence of Candidatus Neoehrlichia mikurensis, we analyzed spleen tissues from 276 voles trapped close to human settlements in France; 5 were infected with the organism. Sequencing showed the isolates carried the same genotype as the bacteria that caused disease in humans and animals elsewhere in Europe.
| S-EPMC3557860 | biostudies-literature
Project description:Candidatus Neoehrlichia came under the focus of recent research in terms of human and pet relevance. Candidatus Neoehrlichia mikurensis seems to be relatively abundant in animals and humans from Central European countries, whereas Candidatus Neoehrlichia lotoris was found solely in raccoons from the USA.Spleen samples from a total of 164 red foxes, originating from two western provinces in Austria (Tyrol and Vorarlberg), were collected and examined for the presence of tick-borne bacteria of the family Anaplasmataceae by PCR and sequencing. In a fox sample originating from Vorarlberg Candidatus Neoehrlichia sp. was found, which is genetically (16S rRNA, groEL) closely related to Candidatus Neoehrlichia lotoris but clearly distinct from Candidatus Neoehrlichia mikurensis.The present study revealed, for the first time, the occurrence of Candidatus Neoehrlichia sp. in a red fox worldwide. A continuing screening of wild carnivores, especially foxes, and ticks for this potential pathogen is required to evaluate the actual occurrence and distribution of these bacteria. Further research is needed to elucidate the relationships of Neoehrlichia, as well as their reservoir and impact on wildlife, pets and humans.
| S-EPMC4608319 | biostudies-literature
Project description:In Europe, human infections with "Candidatus Neoehrlichia mikurensis" have mainly been restricted to immunocompromised patients. We report here the first cases of asymptomatic "Ca. Neoehrlichia mikurensis" infection in immunocompetent humans (5/316 [1.6%] were infected). Due to the potential threats of infections with "Ca. Neoehrlichia mikurensis" in healthy persons to the safety of the blood supply, further study of this phenomenon is required.
| S-EPMC4136151 | biostudies-literature
Project description:Altogether 2004 Ixodes ricinus ticks, from 37 places in Hungary, were analysed in pools with a recently developed multiplex real-time PCR for the presence of Candidatus Neoehrlichia mikurensis and for other representatives of the genus. Ca. Neoehrlichia mikurensis was identified in nine sampling sites, indicating three separated endemic regions along the borders of Hungary. In addition, results of samples from seven places (except for the western part of the country) were positive in the genus-specific (Ca. Neoehrlichia sp.) PCR, but were negative for Ca. Neoehrlichia mikurensis.
| S-EPMC3849741 | biostudies-literature
Project description:Neoehrlichiosis caused by "Candidatus Neoehrlichia mikurensis" is an emerging zoonotic disease. In total, six patients have been described in Europe, with the first case detected in 2007. In addition, seven patients from China were described in a report published in October 2012. In 2009, we diagnosed the first human case of "Ca. Neoehrlichia mikurensis" infection in the Zurich area (Switzerland). Here, we report two additional human cases from the same region, which were identified by broad-range 16S rRNA gene PCR. Both patients were immunocompromised and presented with similar clinical syndromes, including fever, malaise, and weight loss. A diagnostic multiplex real-time PCR was developed for specific detection of "Ca. Neoehrlichia mikurensis" infections. The assay is based on the signature sequence of a 280-bp fragment of the "Ca. Neoehrlichia mikurensis" 16S rRNA gene and incorporates a "Ca. Neoehrlichia mikurensis" species, a "Ca. Neoehrlichia" genus, and an Anaplasmataceae family probe for simultaneous screening. The analytical sensitivity was determined to be below five copies of the "Ca. Neoehrlichia mikurensis" 16S rRNA gene. Our results show that the assay is suitable for the direct detection of "Ca. Neoehrlichia mikurensis" DNA in clinical samples from, for example, blood and bone marrow. In addition, it allows for monitoring treatment response during antibiotic therapy. Using the same assay, DNA extracts from 1,916 ticks collected in four forests in close proximity to the patients' residences (<3 km) were screened. At all sampling sites, the minimal prevalence of "Ca. Neoehrlichia mikurensis" was between 3.5 to 8% in pools of either nymphs, males, or females, showing a strong geographic association between the three patients and the assumed vector.
| S-EPMC3536216 | biostudies-literature