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Gern, Lise
Nom
Gern, Lise
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Fonction
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Email
lise.gern@unine.ch
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Voici les éléments 1 - 10 sur 17
- PublicationMétadonnées seulementSeasonality of Ixodes ricinus ticks on vegetation and on rodents and Borrelia burgdorferi sensu lato genospecies diversity in two Lyme borreliosis endemic areas in Switzerland(2012-1-1)
; - PublicationMétadonnées seulementDeteccion molecular de patogenos emergentes de importancia medica y veterinaria en garrapatas capturadas sobre caballos domesticos(2009-1-1)
; ; - PublicationMétadonnées seulementBorrelia afzelii ospC genotype diversity in Ixodes ricinus questing ticks and ticks from rodents in two Lyme borreliosis endemic areas: contribution of co-feeding ticks(2011-1-1)
; - PublicationMétadonnées seulementPrevalence of three zoonotic Babesia species in Ixodes ricinus nymphs in a suburban forest in Switzerland(2011-4-1)
; ; - PublicationMétadonnées seulementBorrelia burgdorferi genospecies detection by RLB hybridization in Ixodes cinus ticks from different sites of North-Eastern Poland(2014)
; ; - PublicationMétadonnées seulement
- PublicationAccès libreCross-immunity and community structure of a multiple-strain pathogen in the tick vector(2015-11)
; ; ; ; ; Many vector-borne pathogens consist of multiple strains that circulate in both the vertebrate host and the arthropod vector. Characterization of the community of pathogen strains in the arthropod vector is therefore important for understanding the epidemiology of mixed vector-borne infections. Borrelia afzelii and B. garinii are two species of tick-borne bacteria that cause Lyme disease in humans. These two sympatric pathogens use the same tick, Ixodes ricinus, but are adapted to different classes of vertebrate hosts. Both Borrelia species consist of multiple strains that are classified using the highly polymorphic ospC gene. Vertebrate cross-immunity against the OspC antigen is predicted to structure the community of multiple-strain Borrelia pathogens. Borrelia isolates were cultured from field-collected I. ricinus ticks over a period spanning 11 years. The Borrelia species of each isolate was identified using a reverse line blot (RLB) assay. Deep sequencing was used to characterize the ospC communities of 190 B. afzelii isolates and 193 B. garinii isolates. Infections with multiple ospC strains were common in ticks, but vertebrate cross-immunity did not influence the strain structure in the tick vector. The pattern of genetic variation at the ospC locus suggested that vertebrate cross-immunity exerts strong selection against intermediately divergent ospC alleles. Deep sequencing found that more than 50% of our isolates contained exotic ospC alleles derived from other Borrelia species. Two alternative explanations for these exotic ospC alleles are cryptic coinfections that were not detected by the RLB assay or horizontal transfer of the ospC gene between Borrelia species. - PublicationMétadonnées seulement
- PublicationAccès librePrevalence of Borrelia burgdorferi Sensu Lato in Ticks Collected from Migratory Birds in Switzerland(2006)
; ; ; - PublicationAccès libreTick bites in a Lyme borreliosis highly endemic area in Switzerland(2009)
; ; The duration of tick feeding is an important indicator to evaluate the risk of Borrelia burgdorferi sensu lato transmission, which increases considerably with the blood meal duration. This blood meal duration may be estimated from scutal index, the ratio between body length (idiosoma) and scutum width. For the estimation of blood meal duration in Ixodes ricinus, nymphal and adult female ticks were detached at predetermined intervals (24, 48, 72, and 96 h) from laboratory mice and rabbits and their scutal index calculated. From this, non-linear regression equations were developed to determine the duration of attachment for nymphal and adult female I. ricinus ticks. As part of an epidemiological study addressing the risk of subclinical (seroconversion) and clinical infections after a tick bite in the Neuchâtel area (Switzerland) over 3 years (2003–2005), duration of tick attachment and anatomical site of bites collected on participants as well as seasonal distribution of tick bites were studied. Tick attachment duration was estimated in all ticks collected during this study (n=261). Nymphs were attached for a mean (± standard error, SE) of 31.6 h (±2.6) and females for a mean (±SE) of 29.6 h (±3.2). Most nymphs were removed after 24 h of blood meal whereas most females were removed before 24 h. Legs were the major anatomical sites of bites for women (40.7%), men (44.4%), and almost all age classes. Only children <10 years old were bitten more frequently on the head (41.2%) and on the neck (38.5%) than participants >10 years. The majority of tick bites were recorded from May to July during the 3 years. Attachment sites can influence the discovery of ticks, hence the duration of the tick bite. A detailed body examination after each outing in forest and an early withdrawal of an attached tick is an effective way to prevent Lyme borreliosis.