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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
    Characterization of Borrelia lusitaniae isolates collected in Tunisia and Morocco
    (2005)
    Younsi, Hend
    ;
    Sarih, M'Hammed
    ;
    Jouda, Fatima
    ;
    Godfroid, Edmond
    ;
    Gern, Lise 
    ;
    Bouattour, Ali
    ;
    Baranton, Guy
    ;
    Postic, Danièle
    Borrelia lusitaniae is a species within the complex Borrelia burgdorferi sensu lato and is infrequently isolated in Europe. In contrast, this species is by far the most predominant in North Africa and in Portugal. In this study, we analyzed the genetic diversity, at several loci, of a large population of isolates from free-living Ixodes ricinus ticks collected in Tunisia and Morocco. We found a moderate diversity of the whole genome by using pulsed-field gel electrophoresis as well as in the ospA gene sequences, compared to a high level of strain homogeneity in the small noncoding ribosomal spacer. In contrast, a high diversity of this locus has been previously reported for Portuguese isolates. We hypothesize that B. lusitaniae strains isolated in North Africa constitute a clone of Portuguese origin.
  • Publication
    Métadonnées seulement
    Apodemus species mice are reservoir hosts of Borrelia garinii OspA serotype 4 in Switzerland
    (2002)
    Hügli, Delphine
    ;
    Hu, Chang Min
    ;
    Humair, Pierre-François
    ;
    Wilske, Bettina
    ;
    Gern, Lise 
    Among Borrelia burgdorferi sensu lato isolates, seven outer surface protein A (OspA) serotypes have been described: serotypes 1 and 2 correspond to B. burgdorferi sensu stricto and Borrelia afzelii, respectively, and serotypes 3 to 7 correspond to Borrelia garinii. In Europe, serotype 4 has never been isolated from Ixodes ricinus ticks until recently, although this serotype has been frequently isolated from cerebrospinal fluid from patients. In Europe, B. afzelii and B. burgdorferi sensu stricto were found associated with rodents and B. garinii was found associated with birds. In this study, the reservoir role of Apodemus mice for B. garinii OspA serotype 4 was demonstrated by xenodiagnosis. Apodemus mice are the first identified reservoir hosts for B. garinii OspA serotype 4.
  • Publication
    Métadonnées seulement
    Transmission of Borrelia garinii OspA serotype 4 to BALB/c mice by Ixodes ricinus ticks collected in the field
    (2001)
    Hu, Chang Min
    ;
    Wilske, Bettina
    ;
    Fingerle, Volker
    ;
    Lobet, Yves
    ;
    Gern, Lise 
    In Europe, Borrelia garinii OspA serotype 4 has been isolated from the cerebrospinal fluid of patients but, up to now, has never been identified among culture isolates from Ixodes ricinus ticks. This information raises the question of whether OspA serotype 4 is transmitted by I. ricinus in nature. In the present study, L ricinus nymphs collected in an area of endemicity in southern Germany were allowed to feed on mice. Cultivation of ear biopsy specimens showed that six of seven B. garinii-infected mice were infected by OspA serotype 4. In contrast, very few B. garinii OspA serotype 4 organisms were isolated directly from the ticks which infected the mice; most isolates were B. afzelii. The infected mice transmitted mainly OspA serotype 4 to xenodiagnostic ticks, preferentially in combination with B. afzelii.
  • 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.