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Gern, Lise

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

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  • Publication
    Métadonnées seulement
    Detection and identification of Borrelia burgdorferi sensu lato genospecies in ticks from three different regions in Slovakia
    (2007)
    Smetanova, Katarina
    ;
    Burri, Caroline
    ;
    Perez, David
    ;
    Gern, Lise 
    ;
    Kocianova, Elena
    Lyme borreliosis is one of the most common tick-borne diseases that occur in Slovakia. In this study, Borrelia burgdorferi sensu lato was detected and cultivated from questing ticks collected in three areas of Slovakia. Two methods, restriction fragment length polymorphism and reverse line blot, were used for identification of isolates and determination of the prevalence of B. burgdorferi s.l. in the ticks. The prevalence of B. burgdorferi s.l. in I. ricinus detected by reverse line blot was 31.9%. Four genospecies, namely B. garinii, B. valaisiana, B. afzelii and B. burgdorferi sensu stricto were found. B. garinii was the most prevalent genospecies.
  • 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
    Ixodes ricinus density, and distribution and prevalence of Borrelia burgdorferi sensu lato infection along an altitudinal gradient
    (2004)
    Jouda, Fatima
    ;
    Perret, Jean-Luc
    ;
    Gern, Lise 
    In this study, we measured the phenology of Ixodes ricinus ticks and their infection with Borrelia burgdorferi sensu lato (sl) simultaneously along an altitudinal gradient to assess the impact of climate on the phenology of ticks and on their infection with B. burgdorferi sl. From 1999 to 2001, free-living I. ricinus ticks were collected monthly by flagging vegetation at three different altitudes (620, 740, and 900 in above sea level) on the slope of a mountain in Chaumont (Neuchatel, Switzerland). I. ricinus ticks were examined for the presence of B, burgdorferi sl by using direct fluorescent antibody assay and isolation of spirochetes. Borrelia species were characterized by polymerase chain reaction followed by restriction fragment-length polymorphism. Tick density and tick phenology varied with altitude. Although the peak tick density decreased and the onset of ticks was delayed with altitude, the phenology, vas much more stable among years at the highest altitudes than at the lowest. The prevalence of B. burgdorferi infection in nymphs and adults decreased with altitude. The prevalence of infection differed significantly among years, and it was significantly higher in adults (30%) than in nymphs (21%). B. burgdorferi infection in adults was positively related with adult density, but this was not observed for nymphs. Five B. burgdorferi sl genospecies were successfully : B. garinii, B. burgdorferi sensu stricto, B. afzelii, B. valaisiana, and B. lusitaniae. Mixed isolate infections were obtained from five of 140 infected ticks. The greatest diversity in Borrelia species was observed at the lowest altitude where all five Borrelia species were present, whereas at the two highest altitudes, B. lusitaniae was not observed.
  • Publication
    Métadonnées seulement
    Coinoculation of Borrelia spp. with tick salivary gland lysate enhances spirochete load in mice and is tick species-specific
    (2002)
    Zeidner, Nordin S
    ;
    Schneider, Bradley S
    ;
    Nuncio, Maria S
    ;
    Gern, Lise 
    ;
    Piesman, Joseph
    C3H/HeN mice were inoculated with 10(6) spirochetes, either Borrelia burgdorferi strain N40 or the Portuguese strain of B. lusitaniae, PotiB2. Mice receiving spirochetes comoculated with salivary gland lysate (SGL) demonstrated significantly higher spirochete loads in target organs as measured by quantitative real-time polymerase chain reaction. This effect was tick dependent. in that Ixodes ricinus SGL specifically enhanced B. lusitaniae load, whereas I. scapidaris SGL specifically increased B. burgdorferi N40 load, but did not significantly affect the dissemination of B. lusitaniae. Protein profile analysis indicated at least 5 major protein differences between I. scapiularis and I. ricinus SGL, which can possibly account for this specific tick-spirochete interaction.
  • Publication
    Métadonnées seulement
    Infection of Ixodes ricinus (Acari : Ixodidae) by Borrelia burgdorferi sensu lato in North Africa
    (1999)
    Zhioua, Elyes
    ;
    Bouattour, Ali
    ;
    Hu, Chang Min
    ;
    Gharbi, Mohamed
    ;
    Aeschliman, Andre
    ;
    Ginsberg, Howard S
    ;
    Gern, Lise 
    Free-living adult Ixodes ricinus. were collected in Amdoun, situated in the Kroumiry mountains in northwestern Tunisia (North Africa). Using direct fluorescence antibody assay, the infection rate of field-collected I. ricinus bq Borrelia burgdorferi sensu late was 30.5% (n = 72). No difference in infection rate was observed between male and female ticks. Spirochetes that had been isolated from I. ricinus from Ain Drahim (Kroumiry Mountains) in 1988 were identified as Borrelia lusitaniae (formerly genospecies PotiB2). This is the first identification of a genospecies of Borrelia burgdorferi sensu lato from the continent of Africa.