| 1. |
- Chiappa, Giulia, et al.
(author)
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A Novel High Discriminatory Protocol for the Detection of Borrelia afzelii, Borrelia burgdorferi Sensu Stricto and Borrelia garinii in Ticks
- 2022
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In: Pathogens. - : MDPI. - 2076-0817. ; 11:11
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Journal article (peer-reviewed)abstract
- Bacteria of the Borrelia burgdorferi sensu lato complex are the causative agents of Lyme borreliosis (LB). Even if the conventional diagnosis of LB does not rely on the species itself, an accurate species identification within the complex will provide a deepened epidemiological scenario, a better diagnosis leading to a more targeted therapeutic approach, as well as promote the general publics awareness. A comparative genomics approach based on the 210 Borrelia spp. genomes available in 2019 were used to set up three species-specific PCR protocols, able to detect and provide species typing of Borrelia afzelii, Borrelia burgdorferi sensu stricto (s.s.) and Borrelia garinii, the three most common and important human pathogenic Lyme Borrelia species in Europe. The species-specificity of these protocols was confirmed on previously identified B. afzelii, B. burgdorferi s.s. and B. garinii specimens detected in Ixodes ricinus samples. In addition, the protocols were validated on 120 DNA samples from ticks collected in Sweden, showing 88% accuracy, 100% precision, 72% sensitivity and 100% specificity. The proposed approach represents an innovative tool in epidemiological studies focused on B. burgdorferi s.l. occurrence in ticks, and future studies could suggest its helpfulness in routine diagnostic tests for health care.
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| 2. |
- Hoffman, Tove, et al.
(author)
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Alkhurma Hemorrhagic Fever Virus RNA in Hyalomma rufipes Ticks Infesting Migratory Birds, Europe and Asia Minor
- 2018
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In: Emerging Infectious Diseases. - Atlanta, United States : U.S. Department of Health and Human Services * Centers for Disease Control and Prevention. - 1080-6040 .- 1080-6059. ; 24:5, s. 879-882
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Journal article (peer-reviewed)abstract
- Alkhurma hemorrhagic fever virus RNA was detected in immature Hyalomma rufipes ticks infesting northward migratory birds caught in the North Mediterranean Basin. This finding suggests a role for birds in the ecology of the Alkhurma hemorrhagic fever virus and a potential mechanism for dissemination to novel regions. Increased surveillance is warranted.
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| 3. |
- Hoffman, Tove, et al.
(author)
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Association between guilds of birds in the African-Western Palaearctic region and the tick species Hyalomma rufipes, one of the main vectors of Crimean-Congo hemorrhagic fever virus.
- 2022
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In: Microorganisms. - : MDPI AG. - 2076-2607. ; 10
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Journal article (peer-reviewed)abstract
- The migratory behavior of wild birds contributes to the geographical spread of ticks and their microorganisms. In this study, we aimed to investigate the dispersal and co-occurrence of Francisella and spotted fever group Rickettsia (SFGR) in ticks infesting birds migrating northward in the African-Western Palaearctic region (AWPR). Birds were trapped with mist nests across the Mediterranean basin during the 2014 and 2015 spring migration. In total, 575 ticks were collected from 244 birds. We screened the ticks for the species Francisella tularensis, the genus Francisella, and SFGR by microfluidic real-time PCR. Confirmatory analyses and metagenomic sequencing were performed on tick samples that putatively tested positive for F. tularensis during initial screenings. Hyalomma rufipes was the most common tick species and had a high prevalence of Francisella, including co-occurrence of Francisella and SFGR. Metagenomic analysis of total DNA extracted from two H. rufipes confirmed the presence of Francisella, Rickettsia, and Midichloria. Average nucleotide identity and phylogenetic inference indicated the highest identity of the metagenome-assembled genomes to a Francisella-like endosymbiont (FLE), Rickettsia aeschlimannii, and Midichloria mitochondrii. The results of this study suggest that (i) FLE- and SFGR-containing ticks are dispersed by northbound migratory birds in the AWPR, (ii) H. rufipes likely is not involved in transmission of F. tularensis in the AWPR, and (iii) a dual endosymbiosis of FLEs and Midichloria may support some of the nutritional requirements of H. rufipes.
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| 4. |
- Hoffman, Tove, et al.
(author)
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Co-occurrence of Francisella and spotted fever group Rickettsia in avian-associated Hyalomma rufipes
- 2022
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In: Microorganisms. - : MDPI. - 2076-2607. ; 10:7
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Journal article (peer-reviewed)abstract
- Introduction: The migratory behaviour of wild birds aids in the geographical spread of ticks and their microorganisms. Ticks are known to harbor both pathogenic and symbiotic bacteria - such as species of the genera Francisella, Rickettsia,and Midichloria - and multiple bacterial species may occur within them. Francisella occurs in different tick taxa andconsists of closely related pathogenic and non-pathogenic species. Spotted fever group Rickettsia are transmitted to humans by different tick genera and are emerging human pathogens in Europe. The aims of this study were to investigate dispersal of Francisella as well as co-occurrence of Francisella and spotted fever group Rickettsia in ticks infesting northward migrating birds in the African-Western Palaearctic region.Materials and methods: Birds were trapped using mist nets at bird observatories in Spain, Italy, Greece, and Israel during their spring migration of 2014 and 2015. Ticks were screened for the genus Francisella, the species Francisella tularensis, and spotted fever group Rickettsia by microfluidic qPCR. Ticks with putative positive results for F. tularensiswere subjected to confirmation analyses, metagenomics analysis, enrichment, and whole genome sequencing.Results: There was a high prevalence of Francisella species (76.7%) and co-occurrence of Francisella species and spotted fever group Rickettsia (50.6%) in the tick species Hyalomma rufipes. Two H. rufipes yielded putative positive test results for the human pathogen F. tularensis during initial screening. Metagenomics analysis revealed presence of Francisella sp., Rickettsia sp., and Midichloria sp. DNA in the two H. rufipes ticks. The levels of Rickettsia and Midichloria DNA were relatively high while the level of Francisella DNA was low and required enrichment for the construction of metagenome-assembled genomes. Phylogenetic inference and calculations of the average nucleotide identity (ANI) indicated that: i) the Francisella genomes belonged to the Francisella-like endosymbiont (FLE) group in Clade 1 of Francisella and had highest sequence identity to an FLE found in Ornithodoros moubata (ANI: 96.7/97.0%), ii) the Rickettsia genomes had highest resemblance to Rickettsia aeschlimannii (ANI: 98.8 - 99.9%), and iii) the Midichloria genomes resembled Midichloria mitochondrii (ANI: 91.5 - 92.3%).Conclusions: The results of this study suggest ticks containing Francisella species, FLEs, and spotted fever groupRickettsia are dispersed by northbound migratory birds in the African-Western Palaearctic and suggest H. rufipes may not be involved in the transmission of F. tularensis in the study region. Future studies should aim at confirming the prevalence of Francisella spp. and spotted fever group Rickettsia in H. rufipes, in addition to focusing on the influence of FLEs on H. rufipes and their interaction with pathogenic and symbiotic bacteria of the genera Rickettsia and Midichloria.
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| 5. |
- Hoffman, Tove, et al.
(author)
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Co-Occurrence of Francisella, Spotted Fever Group Rickettsia, and Midichloria in Avian-Associated Hyalomma rufipes
- 2022
-
In: Microorganisms. - : MDPI. - 2076-2607. ; 10:7
-
Journal article (peer-reviewed)abstract
- The migratory behavior of wild birds contributes to the geographical spread of ticks and their microorganisms. In this study, we aimed to investigate the dispersal and co-occurrence of Francisella and spotted fever group Rickettsia (SFGR) in ticks infesting birds migrating northward in the African-Western Palaearctic region (AWPR). Birds were trapped with mist nests across the Mediterranean basin during the 2014 and 2015 spring migration. In total, 575 ticks were collected from 244 birds. We screened the ticks for the species Francisella tularensis, the genus Francisella, and SFGR by microfluidic real-time PCR. Confirmatory analyses and metagenomic sequencing were performed on tick samples that putatively tested positive for F. tularensis during initial screenings. Hyalomma rufipes was the most common tick species and had a high prevalence of Francisella, including co-occurrence of Francisella and SFGR. Metagenomic analysis of total DNA extracted from two H. rufipes confirmed the presence of Francisella, Rickettsia, and Midichloria. Average nucleotide identity and phylogenetic inference indicated the highest identity of the metagenome-assembled genomes to a Francisella-like endosymbiont (FLE), Rickettsia aeschlimannii, and Midichloria mitochondrii. The results of this study suggest that (i) FLE- and SFGR-containing ticks are dispersed by northbound migratory birds in the AWPR, (ii) H. rufipes likely is not involved in transmission of F. tularensis in the AWPR, and (iii) a dual endosymbiosis of FLEs and Midichloria may support some of the nutritional requirements of H. rufipes.
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| 6. |
- Saegerman, Claude, et al.
(author)
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First Expert Elicitation of Knowledge on Possible Drivers of Observed Increasing Human Cases of Tick-Borne Encephalitis in Europe
- 2023
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In: Viruses. - : MDPI AG. - 1999-4915. ; 15:3
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Journal article (peer-reviewed)abstract
- Tick-borne encephalitis (TBE) is a viral disease endemic in Eurasia. The virus is mainly transmitted to humans via ticks and occasionally via the consumption of unpasteurized milk products. The European Centre for Disease Prevention and Control reported an increase in TBE incidence over the past years in Europe as well as the emergence of the disease in new areas. To better understand this phenomenon, we investigated the drivers of TBE emergence and increase in incidence in humans through an expert knowledge elicitation. We listed 59 possible drivers grouped in eight domains and elicited forty European experts to: (i) allocate a score per driver, (ii) weight this score within each domain, and (iii) weight the different domains and attribute an uncertainty level per domain. An overall weighted score per driver was calculated, and drivers with comparable scores were grouped into three terminal nodes using a regression tree analysis. The drivers with the highest scores were: (i) changes in human behavior/activities; (ii) changes in eating habits or consumer demand; (iii) changes in the landscape; (iv) influence of humidity on the survival and transmission of the pathogen; (v) difficulty to control reservoir(s) and/or vector(s); (vi) influence of temperature on virus survival and transmission; (vii) number of wildlife compartments/groups acting as reservoirs or amplifying hosts; (viii) increase of autochthonous wild mammals; and (ix) number of tick species vectors and their distribution. Our results support researchers in prioritizing studies targeting the most relevant drivers of emergence and increasing TBE incidence.
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