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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
    Accès libre
    Early detection of Borrelia burgdorferi sensu lato infection in Balb/c mice by co-feeding Ixodes ricinus ticks
    (2003)
    Hu, Chang Min
    ;
    Cheminade, Yves
    ;
    Perret, Jean-Luc
    ;
    Weynants, Vincent
    ;
    Lobet, Yves
    ;
    Gern, Lise 
    In Europe, Borrelia burgdorferi is transmitted by Ixodes ricinus to animals and human. When infected and uninfected ticks co-feed on a host, spirochetes are transmitted from ticks to animal and also to uninfected ticks. Here, we used uninfected ticks to co-feed with infected ticks on mice to evaluate this method to detect early infection in mice. A total of 128 mice were challenged by infected nymphs placed in capsules glued on the back of the mice. Three days later uninfected larvae were added in the capsule to co-feed with infected nymphs and were examined for Borrelia infection after natural detachment. Infection in mice was also determined by xenodiagnosis and by spirochete isolation from ear skin biopsy and back skin biopsy taken at the tick attachment site one month after infection. A total of 111 mice were found to be infected by at least one of these four methods. Borrelia infection was observed in 95% of mice by the co-feeding method, in 92% of mice by xenodiagnosis, in 69% and in 68% of mice by cultivation of ear and back skin biopsies, respectively. Our results demonstrate that the co-feeding method is a very sensitive method which can be used to detect very early infection in mice infected by tick bites.
  • 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
    Antigenic conservation of an immunodominant invariable region of the VlsE lipoprotein among European pathogenic genospecies of Borrelia burgdorferi SL
    (2000)
    Liang, Fang Ting
    ;
    Aberer, Elisabeth
    ;
    Cinco, Marina
    ;
    Gern, Lise 
    ;
    Hu, Chang Min
    ;
    Lobet, Yves
    ;
    Ruscio, Maurizio
    ;
    Voet, Pierre
    ;
    Weynants, Vincent
    ;
    Philipp, Mario T
    Lyme disease is caused by genetically divergent spirochetes, including 3 pathogenic genospecies: Borrelia burgdorferi sensu stricto, B. garinii, and B. afzelii. Serodiagnosis is complicated by this genetic diversity. A synthetic peptide (C-6), based on the 26-mer invariable region (IR6) of the variable surface antigen of B. burgdorferi (VlsE), was used as ELISA antigen, to test serum samples collected from mice experimentally infected with the 3 genospecies and from European patients with Lyme disease, Regardless of the infecting strains, mice produced a strong antibody response to C-6, which indicates that IR6 is antigenically conserved among the pathogenic genospecies. Twenty of 23 patients with culture-confirmed erythema migrans had a detectable antibody response to C-6, A sensitivity of 95.2% was achieved, with serum samples collected from patients with well-defined acrodermatitis chronica atrophicans, Fourteen of 20 patients with symptoms of late Lyme disease also had a positive anti-IR6 ELISA, Thus, it is possible that C-6 may be used to serodiagnose Lyme disease universally.
  • Publication
    Métadonnées seulement
    Immunization with a polyvalent OspA vaccine protects mice against Ixodes ricinus tick bites infected by Borrelia burgdorferi ss, Borrelia garinii and Borrelia afzelii
    (1997)
    Gern, Lise 
    ;
    Hu, Chang Min
    ;
    Voet, Pierre
    ;
    Hauser, Pierre
    ;
    Lobet, Yves
    Sequence variability of the outer surface protein (Osp) A among Borrelia burgdorferi sl species suggests that a monovalent OspA vaccine may not protect against the various Borrelia present in Eurasia. Here, we confirmed that a monovalent recombinant OspA (rOspA) vaccine noes not protect mice against Ixodes ricinus mediated infection with B. burgdorferi ss, Borrelia garinii and Borrelia afzelii. However when mice were vaccinated with a cocktail of various rOspA from these three species, they were protected, and all challenge ricks that fed on them were cleared of their spirochetes. These results showed that a multiple OspA antigens vaccine, compatible with human use, was very efficient at protecting mice against B. burgdorferi ss, B. garinii and B. afzelii. (C) 1997 Elsevier Science Ltd.