Browsing by Author "Ramos, J.A."
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- Avian malaria infections in western European mosquitoesPublication . Ventim, R.; Ramos, J.A.; Osório, H.; Lopes, R.J.; Pérez-Tris, J.; Mendes, L.Avian malaria infections in western European mosquitoes. Ventim R, Ramos JA, Osório H, Lopes RJ, Pérez-Tris J, Mendes L. SourceInstitute of Marine Research (IMAR/CMA), Department of Life Sciences, University of Coimbra, Apartado 3046, 3001-401 Coimbra, Portugal. ritaventim@gmail.com Abstract In the complex life cycle of avian malaria parasites (Plasmodium sp.), we still have a poor understanding on the vector-parasite relationships. This study described the community of potential avian malaria vectors in four Portuguese reedbeds. We tested if their geographical distribution differed, and investigated on their Plasmodium infections. The mosquitoes' feeding preferences were evaluated using CO(2), mice, and birds as baits. The most abundant species were Culex pipiens, Culex theileri, and Ochlerotatus caspius (and, in one site, Coquillettidia richiardii). Plasmodium lineages SGS1 and SYAT05 were found in unengorged Cx. pipiens and Cx. theileri, respectively, suggesting that these mosquitoes were competent vectors of those lineages. The species' abundance was significantly different among sites, which may help to explain the observed differences in the prevalence of SGS1. At the study sites, SGS1 was detected in the most abundant mosquito species and reached a high prevalence in the most abundant passerine species. Probably, this parasite needs abundant hosts in all phases of its cycle to keep a good reservoir of infection in all its stages. Cq. richiardii showed an opportunistic feeding behavior, while Cx. pipiens appeared to be more mammophilic than previously described, perhaps because the used avian bait was not its preferential target. In one of the study sites, mosquitoes seem to be attracted to the Spotless Starling Sturnus unicolor, an abundant bird species that may be an important local reservoir of avian malaria infections. To our knowledge, this is the first report of detection of avian Plasmodium DNA from European mosquitoes.
- 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.
- Borrelia wingmen: dispersal and maintenance of Borrelia burgdorferi s.l. by birdsPublication . Norte, A. C.; Ramos, J.A.; Araújo, P.M.; da Silva, L.P.; Heylen, D.; Costantini, D.; Eens, M.; Núncio, M.S.; Lopes de Carvalho, I.Lyme borreliosis, caused by Borrelia burgdorferi s.l., is the most prevalent vector-borne disease of moderate climates of the northern hemisfere. In Portugal, several Borrelia genospecies are present in questing ticks, which have different associations with vertebrate reservoir hosts and Lyme borreliosis etiology. To better understand disease risk it is necessary to evaluate the relationships among Borrelia genospecies, their tick vectors and vertebrate reservoir hosts.
- 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.
- 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.
- A importância das aves como hospedeiros de carraças e no ciclo enzoótico da Borrelia burgdorferi s.l. em PortugalPublication . Norte, A.C.; Ramos, J.A.; Araújo, P.M.; Pascoal da Silva, L.; Tenreiro, P.Q.; Escudero, R.; Anda, P.; Gern, L.; Zé-Zé, L.; Núncio, M.S.; Lopes de Carvalho, I.As aves selvagens são frequentemente infestadas por carraças e são consideradas reservatório da Borrelia burgdorferi s.l. (sensu lato), um complexo de bactérias transmitidas por carraças, que causam a borreliose de Lyme. De 2010 a 2014 recolhemos 2820 carraças de 690 aves infestadas pertencentes a 40 espécies, e avaliámos a infecção por B. burgdorferi s.l. por nested PCR nestas carraças. Oito espécies de carraças foram identificadas, sendo, Ixodes frontalis (37%) e I. ricinus (34%) as espécies mais comuns. O Melro (Turdus merula) e o Pisco-de-peito-ruivo (Erithacus rubecula) foram as espécies mais infestadas, possivelmente devido aos seus hábitos de pesquisa de alimento a níveis mais baixos. Carraças do género Ixodes sp. infectadas com Borrelia burgdorferi s.l. foram recolhidas de Tentilhões (Fringilla coelebs), Chapins-reais (Parus major), Toutinegras-dosvalados (Sylvia melanocephala), Carriças (Troglodytes troglodytes), Tordos-ruivos (Turdus iliacus), Melros (T. merula) e Tordos-pintos (Turdus philomelos), com maior prevalência em carraças provenientes de T. philomelos (26%). Detectámos B. turdi (4,4%), B. valaisiana (3,7%), B. garinii (3,3%), B. miyamotoi (0,06%) e B. bissettii (0,06%) em Ixodes sp. recolhidas das aves. A caracterização genética das linhagens de B. turdi sugere divergência filogenética da linhagem originalmente detectada no Japão. Uma experiência de xenodiagnóstico provou a capacidade reservatório de T. merula para B. valaisiana e B. turdi. Estes resultados reforçam o papel das aves como agentes chave na manutenção de diferentes genoespécies do complexo B. burgdorferi s.l.
- On the trail of Borrelia burgdorferi s.l.: the key role of birds and lizards as reservoirs for the etiologic agent of Lyme borreliosis in PortugalPublication . Norte, A.C.; Ramos, J.A.; Da Silva, L P.; Araújo, P.M.; Tenreiro, P.Q.; Alves da Silva, A.; Alves, J.; Gern, L.; Núncio, M.S.; Lopes de Carvalho, I.Lyme borreliosis, is a tick-borne disease caused by Borrelia burgdorferi sensu lato, that is considered an emerging disease in some regions of the world, namely in Portugal. The aims of this study is the key role of birds and lizards as reservoirs for the etiologic agent of Lyme borreliosis in Portugal.
- Pandora's flying box - Borrelia burgdorferi sensu lato prevalence in Ixodes species from birds throughout EuropePublication . Norte, A. C.; Ramos, J.A.; Núncio, M.S.; Margos, G.; Fingerle, V.; Adamik, P.; Alivizatos, H.; Barba, E.; Barrientos, R.; Cauchard, L.; Csörgo, T.; Diakou, A.; Dingemanse, N.J.; Doligez, B.; Dubiec, A.; Eeva, T.; Flaisz, B.; Grim, T.; Hau, M.; Heylen, D.; Hornok, S.; Kazantzidis, S.; Kováts, D.; Krause, F.; Literak, I.; Mänd, R.; Mentesana, L.; Morinay, J.; Mutanen, M.; Neto, J.; Nováková, M.; Sanz, J.J.; Silva, L.P.; Sprong, H.; Tirri, I.S.; Török, J.; Trilar, T.; Tyller, Z.; Visser, M.E.; Lopes de Carvalho, I.Birds are important hosts for ticks and may act as reservoirs for several zoonotic pathogens. Because of their high mobility, especially of the long distance migratory species, they can act as dispersers for ticks and pathogens, ultimately affecting their distribution and phylogeography.