Browsing by Author "Gern, L."
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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.
- 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.
- Do ticks and Borrelia burgdorferi s.l. constitute a burden to birds?Publication . Norte, A.; Lobato, D.; Braga, E.; Antonini, Y.; Lacorte, G.; Gonçalves, M.; Lopes de Carvalho, I.; Gern, L.; Núncio, M.; Ramos, J.Ticks consume resources from their hosts shaping their life-history traits and are vectors of many zoonotic pathogens. Several studies have focused on the health effects of blood sucking ectoparasites on avian hosts, but there is limited information on the effects of ticks on adult and sub-adult birds, which may actively avoid ticks and are likely to present low infestation intensities. We evaluated the effects of the presence of feeding ticks and intensity of infestation on health variables of avian hosts. We also evaluated whether these variables were affected by tick infection by Borrelia burgdorferi sensu lato (s.l.) and by the presence of Borrelia infection on the birds’ skin. Presence of parasite association among ticks, haemosporidea and Borrelia within the bird-host was also tested. We found that infestation by ticks significantly increased heterophyl/lymphocyte ratio in Turdus merula suggesting increased stress. This was especially evident at high infestation intensities when a significant decrease in body mass and body condition (body mass corrected for size) was also observed. Erithacus rubecula infested with more than ten larvae tended to have lower haematocrit and blood haemoglobin. Plasma globulin concentration in T.merula tended to be affected by the presence of attached ticks and their infection with Borrelia, but this depended on the age of the bird. No association was detected among ticks, haemosporidea and Borrelia infection. We showed that ticks have detrimental effects on their avian hosts even under natural infestation conditions and that confirmed Borrelia reservoir hosts may also present symptoms of infection, though these may be subtle.
- 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.