Browsing by Author "Norte, A.C."
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- Birds as reservoirs for Borrelia burgdorferi s.l. in Western Europe: circulation of B. turdi and other genospecies in bird-tick cycles in PortugalPublication . Norte, A.C.; Ramos, J.A.; Gern, L.; Núncio, M.S.; Lopes de Carvalho, I.Birds as reservoirs for Borrelia burgdorferi s.l. in Western Europe: circulation of B. turdi and other genospecies in bird-tick cycles in Portugal. Norte AC, Ramos JA, Gern L, Núncio MS, Lopes de Carvalho I. SourceInstitute of Marine Research IMAR/CMA, Department of Life Sciences, University of Coimbra, Apartado 3046, 3001-401 Coimbra, Portugal. Center for Vector and Infectious Diseases Research, National Health Institute Doutor Ricardo Jorge, Lisbon, Portugal. Laboratory of Eco-Epidemiology of Parasites, Institute of Biology, University of Neuchâtel, Neuchâtel, Switzerland. Abstract Birds are important in the ecology of Borrelia burgdorferi sensu lato (s.l.) because they are important hosts for vector tick immature stages and are known reservoirs for some Borrelia genospecies. The aim of our study was to assess the role of common passerine bird species as reservoirs for B. burgdorferi s.l. in Western Europe. We surveyed birds in enzootic areas in Portugal, where no information is available for birds as reservoirs for this aetiologic agent and where B. lusitaniae, for which few reservoirs have been identified, is the dominant genospecies. Twenty-three birds (2.9%), including Turdus merula, T. philomelos, Parus major and Fringilla coelebs harboured infected ticks, but only Turdus sp. harboured infected tick larvae. In one study area, although B. lusitaniae was dominant in questing Ixodes ricinus, no ticks feeding on birds were infected with this genospecies, and B. valaisiana was the dominant genospecies in I. ricinus larvae feeding on birds. In the other area ticks collected from birds were mainly I. frontalis which were infected with B. turdi. Two skin biopsies (4.2%) from two T. merula were positive, one for B. valaisiana and the other for B. turdi. This is the first report for B. turdi in Western Europe. © 2012 Society for Applied Microbiology and Blackwell Publishing Ltd. PMID:22882497[PubMed - as supplied by publisher]
- Blackbirds Turdus merula as competent reservoirs for Borrelia turdi and Borrelia valaisiana in Portugal: evidence from a xenodiagnostic experimentPublication . Norte, A.C.; Lopes de Carvalho, I.; Núncio, M.S.; Ramos, J.A.; Gern, L.To confirm that thrushes, such as blackbirds Turdus merula, play a role as reservoir for some Borrelia genospecies, we performed a xenodiagnostic experiment with blackbirds captured in a mixed wood located in Western Portugal where Borrelia turdi, an uncommon genospecies in Europe, was the most prevalent genospecies associated with birds. Two out of five birds harboured B. turdi infected Ixodes frontalis at the time of capture. Four out of five birds transmitted spirochaetes to Ixodes ricinus xenodiagnostic ticks: two birds transmitted Borrelia valaisiana to 25.7% and 10.5% of ticks, and two transmitted B. turdi to 6.4% and 5.4% of ticks. Our results showed that blackbirds transmit B. valaisiana and B. turdi to I. ricinus feeding larvae, acting as reservoir hosts for these genospecies in nature.
- Bridging of cryptic Borrelia cycles in European songbirdsPublication . Heylen, D.; Krawczyk, A.; Lopes de Carvalho, I.; N uncio, M.S.; Sprong, H.; Norte, A.C.The principal European vector for Borrelia burgdorferi s.l., the causative agents of Lyme disease, is the host-generalist tick Ixodes ricinus. Almost all terrestrial host-specialist ticks have been supposed not to contribute to the terrestrial Borrelia transmission cycles. Through an experiment with blackbirds, we show successful transmission by the widespread I. frontalis, an abundant bird-specialized tick that infests a broad range of songbirds. In the first phase of the experiment, we obtained Borrelia-infected I. frontalis (infection rate: 19%) and I. ricinus (17%) nymphs by exposing larvae to wild blackbirds that carried several genospecies (Borrelia turdi, B. valaisiana, B. burgdorferi s.s.). In the second phase, pathogen-free blackbirds were exposed to these infected nymphs. Both tick species were able to infect the birds, as indicated by the analysis of xenodiagnostic I. ricinus larvae which provided evidence for both co-feeding and systemic transmission (infection rates: 10%-60%). Ixodes frontalis was shown to transmit B. turdi spirochetes, while I. ricinus transmitted both B. turdi and B. valaisiana. Neither species transmitted B. burgdorferi s.s. European enzootic cycles of Borrelia between songbirds and their ornithophilic ticks do exist, with I. ricinus potentially acting as a bridging vector towards mammals, including man.
- Core genome phylogenetic analysis of the avian associated Borrelia turdi indicates a close relationship to Borrelia gariniiPublication . Margos, G.; Becker, N.S.; Fingerle, V.; Sing, A.; Ramos, J.A.; Lopes de Carvalho, I.; Norte, A.C.Borrelia burgdorferi sensu lato comprises a species complex of tick-transmitted bacteria that includes the agents of human Lyme borreliosis. Borrelia turdi is a genospecies of this complex that exists in cryptic transmission cycles mainly between ornithophilic tick vectors and their avian hosts. The species has been originally discovered in avian transmission cycles in Asia but has increasingly been found in Europe. Next generation sequencing was used to sequence the genome of B. turdi isolates obtained from ticks feeding on birds in Portugal to better understand the evolution and phylogenetic relationship of this avian and ornithophilic tick-associated genospecies. Here we use draft genomes of these B. turdi isolates for comparative analysis and to determine the taxonomic position within the B. burgdorferi s.l. species complex. The main chromosomes showed a maximum similarity of 93% to other Borrelia species whilst most plasmids had lower similarities. All three isolates had nine or 10 plasmids and, interestingly, one plasmid with a novel partitioning protein; this plasmid was termed lp30. Phylogenetic analysis of multilocus sequence typing housekeeping genes and 113 single copy orthologous genes revealed that the isolates clustered according to their classification as B. turdi. In phylogenies generated from these 113 genes the isolates cluster together with other Eurasian genospecies and form a sister clade to the avian associated B. garinii and the rodent associated B. bavariensis. These findings show that Borrelia species maintained in cryptic ecological cycles need to be included to fully understand the complex ecology and evolutionary history of this bacterial species complex.
- Diversity and seasonal patterns of ticks parasitizing wild birds in western PortugalPublication . Norte, A.C.; Lopes de Carvalho, I.; Ramos, J.A.; Gonçalves, M.; Gern, L.; Núncio, M.S.The diversity and abundance of questing ticks and ticks parasitizing birds was assessed during 1 year in two recreational forests in western Portugal, a suburban forest and an enclosed game area. The aim of this study was to assess the distribution and seasonality of tick species and to understand the role of bird species as hosts for ticks. Ixodes ricinus was the most abundant questing tick collected in the enclosed game area, whereas in the suburban forest, only three ticks were collected by blanket dragging. Tick species parasitizing birds included I. ricinus, I. frontalis, I. arboricola, I. acuminatus, Haemaphysalis punctata, Hyalomma marginatum and H. lusitanicum. This is the first record of I. arboricola in Portugal. Tick prevalence and intensity of infestation differed between study areas and was higher in birds from the game area where a large population of deer and wild boar may support tick populations. Ground and shrub dwelling bird species such as Turdus merula, Erithacus rubecula and Sylvia melanocephala were the most heavily parasitized by ticks, but the importance of different bird species as hosts of larvae and nymphs of I. ricinus and I. frontalis differed. Therefore, different bird species may contribute differently for tick population maintenance.
- Diversity of microorganisms in Hyalomma aegyptium collected from spur-thighed tortoise (Testudo graeca) in North Africa and AnatoliaPublication . Norte, A.C.; Harris, D.J.; Silveira, D.; Nunes, C.S.; Núncio, M.S.; Martínez, E.G.; Giménez, A.; Sousa, R.; Lopes de Carvalho, I.; Perera, A.Ticks carry a diverse community of microorganisms including non-pathogenic symbionts, commensals, and pathogens, such as viruses, bacteria, protozoans, and fungi. The assessment of tick-borne microorganisms (TBM) in tortoises and their ticks is essential to understand their eco-epidemiology, and to map and monitor potential pathogens to humans and other animals. The aim of this study was to characterize the diversity of microorganisms found in ticks collected from the spur-thighed tortoise (Testudo graeca) in North Africa and Anatolia. Ticks feeding on wild T. graeca were collected, and pathogens were screened by polymerase chain reaction using group-specific primers. In total, 131 adult Hyalomma aegyptium ticks were collected from 92 T. graeca in Morocco (n = 48), Tunisia (n = 2), Algeria (n = 70), and Turkey (n = 11). Bacteria and protozoa detected included Hemolivia mauritanica (22.9%), Midichloria mitochondrii (11.4%), relapsing-fever borreliae (8.4%), Ehrlichia spp. (7.6%), Rickettsia spp. (3.4%), Borrelia burgdorferi s.l. (0.9%), Francisella spp. (0.9%), and Wolbachia spp. (0.8%). The characterization of Rickettsia included R. sibirica mongolitimonae (Algeria), R. aeschlimannii (Turkey), and R.africae (Morocco). Hemolivia mauritanica and Ehrlichia spp. prevalence varied significantly with the sampling region/country. We did not detect significant associations in microorganism presence within ticks, nor between microorganism presence and tick mitochondrial DNA haplogroups. This is the first report of Francisella persica-like, relapsing fever borreliae, M. mitochondrii, and Wolbachia spp. in H. aegyptium ticks collected from wild hosts from the South and Eastern Mediterranean region, and of R. sibirica mongolitimonae and R. africae in H. aegyptium from Algeria and Morocco, respectively. Given that T. graeca is a common species in commercial and non-commercial pet trade, the evaluation of the role of this species and its ticks as hosts for TBM is particularly relevant for public health.
- Diversity of microorganisms in Hyalomma aegyptium collected fromspur-thighedtortoise(Testudograeca)in North Africa and AnatoliaPublication . Norte, A.C.; Harris, D.J.; Silveira, D.; Nunes, C.S.; Núncio, M.S.; Martínez, E.G.; Giménez, A.; Sousa, R.; Lopes de Carvalho, I.; Perera, A.Ticks carry a diverse community of microorganisms including non-pathogenic symbionts, commensals, and pathogens, such as viruses, bacteria, protozoans, and fungi. The assessment of tick-borne microorganisms (TBM) in tortoises and their ticks is essential to understand their eco-epidemiology, and to map and monitor potential pathogenstohumansandotheranimals.Theaimofthisstudywastocharacterizethe diversity of microorganisms found in ticks collected from the spur-thighed tortoise (Testudo graeca) in North Africa and Anatolia. Ticks feeding on wild T. graeca were collected, and pathogens were screened by polymerase chain reaction using groupspecific primers. In total, 131 adult Hyalomma aegyptium ticks were collected from 92 T. graeca in Morocco (n = 48), Tunisia (n = 2), Algeria (n = 70), and Turkey (n = 11). Bacteria and protozoa detected included Hemolivia mauritanica (22.9%), Midichloria mitochondrii (11.4%), relapsing-fever borreliae (8.4%), Ehrlichia spp. (7.6%), Rickettsia spp. (3.4%), Borrelia burgdorferi s.l. (0.9%), Francisella spp. (0.9%), and Wolbachia spp. (0.8%). The characterization of Rickettsia included R. sibirica mongolitimonae (Algeria), R. aeschlimannii (Turkey), and R.africae (Morocco). Hemolivia mauritanica and Ehrlichia spp. prevalence varied significantly with the sampling region/country. We did not detect significant associations in microorganism presence within ticks, nor between microorganism presence and tick mitochondrial DNA haplogroups. This is the first report of Francisella persica-like, relapsing fever borreliae, M. mitochondrii, andWolbachia spp. in H.aegyptiumticks collected from wild hosts from the South and Eastern Mediterranean region, and of R. sibirica mongolitimonae and R. africae in H. aegyptium from Algeria and Morocco, respectively. Given that T. graeca is a common species in commercial and non-commercial pet trade, the evaluation of the role of this species anditsticksashostsforTBMisparticularlyrelevantforpublichealth
- Host dispersal shapes the population structure of a tick-borne bacterial pathogenPublication . Norte, A.C.; Margos, G.; Becker, N.S.; Albino Ramos, J.; Núncio, M.S.; Fingerle, V.; Araújo, P.M.; Adamík, P.; Alivizatos, H.; Barba, E.; Barrientos, R.; Cauchard, L; Csörgő, T.; Diakou, A.; Dingemanse, N.J.; Doligez, B.; Dubiec, A.; Eeva, T.; Flaisz, B.; Grim, T.; Hau, M.; Hornok, S.; Kazantzidis, S.; Kováts, D.; Krause, F.; Literak, I.; Mänd, R.; Mentesana, L.; Morinay, J.; Mutanen, M.; Neto, J.M.; Nováková, M.; Sanz, J.J.; Pascoal da Silva, L.; Sprong, H.; Tirri, I.S.; Török, J.; Trilar, T.; Tyller, Z.; Visser, M.E.; Lopes de Carvalho, I.f ticks and their associated pathogens. The life cycle of tick-borne pathogens is complex and their evolutionary ecology is shaped by the interactions with vertebrate hosts and tick vectors (Kurtenbach et al., 2006). This study focused on the ecology and genetic diversity of B. burgdorferi s.l. as a model to investigate the drivers of the population structure and to understand the role of host- associated dispersal on the evolution of tick-borne pathogens. This represents a consequential question in the ecology and evolution of any pathogen. Borrelia burgdorferi s.l. is a bacterial complex of over 20 known genospecies, including the etiologic agents of Lyme borreliosis (Casjens et al., 2011; Margos et al., 2015), whose main vectors are ticks of the genus Ixodes (Eisen & Lane, 2002). These bacteria are widespread in Europe, Asia and North America and are also present in North Africa (Margos, Vollmer, Ogden, & Fish, 2011; Zhioua et al., 1999). Different Borrelia genospecies have different patterns of association with vertebrate reservoir hosts (Humair & Gern, 2000; Kurtenbach, Peacey, et al., 1998) because of the immunological host response, mediated by the action of the host's complement system (Kurtenbach et al., 2002). While B. burgdorferi sensu stricto (s.s.) is a generalist genospecies, Borrelia afzelii is mostly associated with mammalian hosts such as rodents, whereas Borrelia valaisiana, Borrelia garinii and Borrelia turdi are mostly associated with birds (Heylen, 2016; Margos et al., 2011). Because tick vectors cannot move large distances independent of hosts, it has been suggested that host specialization determines the spread and dispersal of B. burgdorferi s.l. genospecies (Kurtenbach et al., 2010; Sonenshine & Mather, 1994). Because birds are both important hosts for some Borrelia genospecies and for various species of vector ticks, they act as a driving force shaping B. burgdorferi s.l. distribution and phylogeographical patterns (Margos et al., 2011; Vollmer et al., 2011). Here, we assessed the role of passerine birds as hosts and dispersers of B. burgdorferi s.l. We tested the hypothesis that infection prevalence with Borrelia genospecie
- Host-parasite interactions between Borrelia burgdorferi s.l. and its avian reservoir hostsPublication . Norte, A.C.; Heylen, D.; Margos, G.; Fingerle, V.; Becker, N.; Araújo, P.M.; da Silva, L.P.; Sprong, H.; Krawczyk, A.; Costantini, D.; Eens, M.; Núncio, M.S.; Ramos, J.A.; Lopes de Carvalho, I.Borrelia burgdorferi sensu lato (s.l.) is maintained in enzootic cycles in nature by vertebrate reservoir hosts, including mammals, lizards and birds. To understand the eco-epidemiology of Lyme borreliosis it is necessary to evaluate the relationships among Borrelia genospecies, their tick vectors and vertebrate reservoir hosts. We surveyed infection prevalence in avian hosts and using wild birds as models, we performed transmission experiments, assessed the physiological impact of infection in reservoir hosts and how exposure to stress could affect the host’s infectivity to vector ticks. Additionally, we evaluated the population structure of an avian-associated Borrelia genospecies.
- Hyalomma ticks infecting tortoises in North Africa and Turkey: distribution, genetic variation and their role as potential vectorsPublication . Perera, A.; Silveira, D.; Graciá, E.; Giménez, A.; Saramago-Nunes, C.; Lopes de Carvalho, I.; Núncio, M.S.; Harris, D.J.; Norte, A.C.Hyalomma aegyptium is the most common tick species infesting tortoises in the Palearctic. Although larvae and nymphs of these ticks feed on different animal groups, adults of H. aegyptium are highly specific to Testudo. Hyalomma are also carriers of various microorganisms, including pathogens. In this symposium we present the results of two studies on Hyalomma ticks infesting Testudo from North Africa and Turkey. In the first, we analysed the genetic diversity of Hyalomma, and assessed whether the genetic patterns of the ticks matched the ones of the Testudo hosts. We identified two main genetic groups of H. aegyptium with no clear geographical structure. We believe that the existence of alternative hosts or the pet trade may explain some of these results. In the second study, we aimed to detect the presence of microorganisms and potential pathogens in H. aegyptium. The molecular screening detected the following parasites: Hemolivia mauritanica, Ehrlichia sp., Borrelia burgdorferi sensu lato, relapsing fever Borrelia, Francisella sp. and the microorganisms Candidatus Midichlora mitochondrii and Wolbachia sp. Despite the low prevalence of human pathogenic agents, these results highlight the potential consequences of the pet trade on disease emergence and the dispersion of pathogens and other microorganisms
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