Vignette d'image

Gern, Lise

Nom
Gern, Lise
Affiliation principale
Fonction
Ancien.ne collaborateur.trice
Identifiants
https://libra.unine.ch/handle/123456789/303

Résultat de la recherche

Filtres

5
5
5
Réinitialiser les filtres

Paramètres

Voici les éléments 1 - 5 sur 5
  • Publication
    Métadonnées seulement
    Identification of host bloodmeal source and Borrelia burgdorferi sensu lato in field-collected Ixodes ricinus ticks in Chaumont (Switzerland)
    (2007)
    Cadenas, Francisca Moran
    ;
    Rais, Olivier 
    ;
    Humair, Pierre-François
    ;
    Douet, Véronique 
    ;
    Moret, Jacqueline
    ;
    Gern, Lise 
    To evaluate the importance of vertebrate species as tick hosts and as reservoir hosts in two endemic areas for Lyme borreliosis in Switzerland, we applied molecular methods for the analysis of bloodmeal source and Borrelia infection in questing Ixodes ricinus L. ticks. In total, 1,326 questing ticks were simultaneously analyzed for Borrelia and for blood meal remnants by using reverse line blot. An overall infection prevalence of 19.0% was recorded for Borrelia sp., with similar rates in both sites. Using a newly developed method for the analysis of bloodmeal targeting the 12S rDNA mitochondrial gene, identification of host DNA from field-collected ticks was possible in 43.6% of cases. Success of host identification at the genus and species level reached 72%. In one site, host identification success reached its maximum in spring (93% in May), decreasing in summer (20% in July) and rising in autumn (73% in October). In the other site, identification rate in ticks remained low from April to July and increased in autumn reaching 68% in October and November. The most prevalent identified host DNA was artiodactyls in both sites. Red squirrel DNA was significantly more frequently detected in ticks collected in one site, whereas insectivore DNA was more frequent in ticks in the other site. DNA from more than one vertebrate host was detected in 19.5% of nymphs and 18.9% of adults. Host DNA was identified in 48.4% of the Borrelia infected ticks. Although DNA from all Borrelia species was found in at least some ticks with DNA from mammals and some ticks with DNA from birds, our results confirm a general association of B. afzelii and B. burgdorferi sensu stricto with rodents, and B. valaisiana and B. garinii with birds.
  • Publication
    Métadonnées seulement
    Reservoir role of lizard Psammodromus algirus in transmission cycle of Borrelia burgdorferi sensu lato (Spirochaetaceae) in Tunisia
    (2006)
    Dsouli, Najla
    ;
    Younsi-Kabachii, Hend
    ;
    Postic, Danièle
    ;
    Nouira, Said
    ;
    Gern, Lise 
    ;
    Bouattour, Ali
    To investigate the reservoir role of the lizard Psammodromus algirus for the Lyme disease spirochete, 199 lizards were trapped from April to October 2003 in El Jouza, northwestern Tunisia. In this site, the infection rate of free-living Ixodes ricinus (L.) by Borrelia was evaluated by immunofluorescence as 34.6% for adult ticks and 12.5% for nymphs. Eighty percent of P. algirus (117/146) captured during this study were infested by I. ricinus, the predominant tick species collected from lizards. The intensity of tick infestation of this host by larvae and nymphs ranged from 0.14 to 7.07 and from 1.5 to 6.58, respectively. These immature stages of I. ricinus were found on lizards in spring and the beginning of summer, with a peak of intensity during June (10.16 immature ticks by lizard). Tissue cultures from lizards and xenodiagnosis with larval L ricinus were used to assess the infection and the ability, respectively, of infected lizards to transmit Borrelia to naive ticks. Seventeen percent of xenodiagnostic ticks (40/229) acquired B. lusitaniae while feeding on P. algirus. Therefore, we demonstrated the ability of the lizards to sustain Borrelia infection and to infect attached ticks, and we proved that P. algirus is a reservoir host competent to transmit B. lusitaniae.
  • Publication
    Métadonnées seulement
    Prevalence of Borrelia burgdorferi sensu lato in ticks collected from migratory birds in Switzerland
    (2006)
    Poupon, Marie-Angèle
    ;
    Lommano, Elena 
    ;
    Humair, Pierre-François
    ;
    Douet, Véronique 
    ;
    Rais, Olivier 
    ;
    Schaad, Michael
    ;
    Jenni, Lukas
    ;
    Gern, Lise 
    The prevalence of ticks infected by Borrelia burgdorferi sensu lato on birds during their migrations was studied in Switzerland. A total of 1,270 birds captured at two sites were examined for tick infestation. Ixodes ricinus was the dominant tick species. Prevalences of tick infestation were 6% and 18.2% for birds migrating northward and southward, respectively. Borrelia valaisiana was the species detected most frequently in ticks, followed by Borrelia garinii and Borrelia lusitaniae. Among birds infested by infected ticks, 23% (6/26) were infested by B. lusitaniae-infected larvae. Migratory birds appear to be reservoir hosts for B. lusitaniae.
  • Publication
    Métadonnées seulement
    First isolation of Borrelia burgdorferi sensu lato from Ixodes ricinus ticks in Morocco
    (2003)
    Sarih, M'Hammed
    ;
    Jouda, Fatima
    ;
    Gern, Lise 
    ;
    Postic, Danièle
    To determine the infection rate of Ixodes ricinus (I. ricinus) ticks with Borrelia burgdorferi sensu lato (B. burgdorferi sl) and to assess the frequency of the individual Borrelia species in this tick species, a total of 295 I. ricinus were collected in Taza region (Northeast of Morocco), from January to June 2002. The presence of B. burgdorferi A was determined by direct fluorescence antibody assay (DFA) and by PCR after culture. B. burgdorferi sl isolates were identified at the species level by restriction fragment length polymorphism. analysis of amplified products. The mean rate of I. ricinus infection with B. burgdorferi sl was 47.8%. Isolation attempts in BSK II medium resulted in 26 pure isolates. However, PCR performed on culture medium allowed to identify 82 Borrelia DNAs. B. lusitaniae has been identified from 76 out of 82 infected I. ricinus ticks (92.7%). Three ticks were infected by B. burgdorferi ss, and three other ticks were infected by B. garinii. This is the first report of the presence of B. burgdorferi A in Morocco and more specifically of B. burgdorferi ss in North Africa.
  • Publication
    Métadonnées seulement
    Transmission cycles of Borrelia burgdorferi sensu lato involving Ixodes ricinus and/or I-hexagonus ticks and the European hedgehog, Erinaceus europaeus, in suburban and urban areas in Switzerland
    (1997)
    Gern, Lise 
    ;
    Rouvinez, Evelyne
    ;
    Toutoungi, Lina Naime
    ;
    Godfroid, Edmond
    European hedgehog, Erinaceus europaeus Linnaeus, 1758, is a common host of Ixodes ricinus L, and I. hexagonus Leach, vectors of the Lyme disease spirochaete, Borrelia burgdorferi sensu lato. TO investigate whether hedgehogs are reservoirs for B. burgdorferi, hedgehogs were captured in a suburban area suitable for both tick species and in an urban area where I, ricinus is absent. The infection status of the hedgehogs was determined by xenodiagnosis using I. ricinus and I. hexagonus larvae. I. hexagonus and/or I. ricinus were found on;ll hedgehogs (n = 8) from the suburban area. In contrast, only I. hexagonus was infesting animals (n = 5) from the urban area. A total of 12/13 hedgehogs harboured B. burgdorferi infected ticks. Xenodiagnostic I. ricinus and I. hexagonus larvae that fed on hedgehogs became infected. The results clearly show that European hedgehogs are reservoir hosts of the Lyme disease spirochetes. DNA of B. burgdorferi sensu stricto, B. garinii and B. afzelii was detected in culture from ear biopsy and needle aspiration material and characterized by using a genospecies-specific PCR assay. One hedgehog presented a mixed infection of the skin with B, burgdorferi sensu stricto and B. garinii. This study also identifies an enzootic transmission cycle in an urban area involving E. europaeus and I. hexagonus. The close association of I. hexagonus with the burrows of its hosts mean that the risks of contact between I. hexagonus and humans may be low.