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- PublicationMétadonnées seulementLongitudinal study of Lyme borreliosis in a high risk population in Switzerland(1998)
;Zhioua, Elyes ; ; ;Sauvain, Marie-Josephe ;Van der Linden, SjefFahrer, HeinzOrienteers from all parts of Switzerland (n = 416) were included in a longitudinal study for lyme borreliosis. In spring 1986, the seroprevalence was 28.1 %. At the beginning of the study, 84.3 % of orienteers reported a history of tick bite, and 3.8 % reported a past history of lyme borreliosis. During the first (spring 1986-autumn 1986), second (autumn 1986-spring 1987) and third (spring 1987-autumn 1987) period, rates of seroconversion were 0.6 % 2.7 % and 2.1 % respectively. During the first and second period, clinical incidence were 1.0 % and 0.25 % respectively. No active lyme borreliosis was detected during the third period. Among orienteers who seroconverted during the study (n = 16), only two developed clinical symptoms. Hence, Borrelia burgdorferi infection is often asymptomatic.
- PublicationMétadonnées seulementEvaluation of a modified culture medium for Borrelia burgdorferi sensu lato(2007)
;Rodriguez, Islay ;Lienhard, Reto ; ;Veuve, Marie Colette ;Jouda, Fatima ;Siegrist, Hans H ;Fernandez, CarmenRodriguez, José EnriqueThe aim of the present study was to assess the possible use of a modified medium, prepared in the laboratory using the constituents of Barb our-Stonner-Kelly (BSK) medium and medium 199 as base, for the culture of Borrelia strains, comparing the growth of individual strains in this medium and in the BSK-H medium, and the protein profile and antigenic characteristics of Borrelia proteins expressed in these media. A qualitative evaluation of growth of Borrelia species was made with acceptable results (morphology and motility), but during a quantitative evaluation using the three main genospecies of Borrelia, the better results were obtained with a B. burgdorferi sensu stricto strain. The modified medium did not enable the growth of a B. afzelii strain. The protein profile and antigenic characteristic of the expressed proteins in the modified medium were studied with satisfactory results. These results suggest the modified medium as an alternative for the cultivation of Borrelia strains, with some limitations, in poorly-resourced laboratories.
- PublicationMétadonnées seulementDensity of questing Ixodes ricinus nymphs and adults infected by Borrelia burgdorferi Sensu Lato in Switzerland: Spatio-temporal pattern at a regional scale(2004)
;Jouda, Fatima ;Perret, Jean-LucLyme borreliosis, the most important vector-borne disease in the Northern hemisphere, causes health problem for populations in endemic areas. In the present study, the density of questing Ixodes ricinus ticks and their infection with Borrelia burgdorferi sensu lato (sl) was examined in 11 areas located on the Swiss Plateau and in an alpine valley. From 1999 to 2001, free-living I. ricinus ticks were collected on a monthly basis by flagging vegetation in these areas. Each tick was examined for the presence of B. burgdorferi A using direct fluorescent antibody assay, and for isolation of the bacteria. Borreliae were characterized by PCR followed by RFLP. Density of questing ticks varied greatly between studied areas. Borreliae were observed in ticks collected in all investigated sites. However, the prevalence of infection differed significantly among areas. Infection prevalence varied from 9% to 40% in nymphs and from 22% to 47% in adults. Adult ticks were significantly more infected (129/366, 35%) than nymphs (109/552, 20%). There was no correlation between nymphal density and infection prevalence as well as between adult density and infection prevalence, but there was a correlation between density of ticks and density of infected ticks. During the spring peak of questing tick density, a range of 2-30.3 infected ticks per 100 m(2) was observed. B. burgdorferi sl isolates (n = 129) were obtained from ticks collected in 10/11 areas. Five Borrelia species were identifed: B. garinii, B. burgdorferi sensu stricto, B. afzelii, B. valaisiana, B. lusitaniae, and six mixed infections were also obtained. Borrelia species were heterogeneously distributed in the different areas.
- PublicationMétadonnées seulementIdentification of host bloodmeal source and Borrelia burgdorferi sensu lato in field-collected Ixodes ricinus ticks in Chaumont (Switzerland)(2007)
;Cadenas, Francisca Moran ; ;Humair, Pierre-François ; ;Moret, JacquelineTo 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.
- PublicationMétadonnées seulementRisk of Borrelia burgdorferi infection in western Switzerland following a tick bite(2004)
;Nahimana, I ; ;Blanc, D S ;Praz, G ;Francioli, PThe aim of this study was to define the risk of developing Lyme borreliosis after a tick bite. A survey was conducted from 1993 to 1995 in the western part of Switzerland in a group of patients who presented for treatment of a recent tick bite. Only patients with negative serological tests (enzyme-linked fluorescent assay screening test, and IgG and IgM immunoblots) at the first consultation and for whom a second blood sample was available 2 months later were included in the study. Of the 376 patients included, 266 had no clinical manifestation (group 1) and 110 had a small local cutaneous reaction (
- PublicationMétadonnées seulementDiversity within Borrielia burgdorferi sensu lato genospecies in Switzerland by recA gene sequence(2004)
;Casati, Simona ;Bernasconi, Marco ;Piffaretti, Jean-ClaudeA total of 874 Ixodes ricinus ticks were collected in Switzerland to investigate the genetic diversity of the Borrelia population. We integrated to the RT-PCR method the DNA sequence analysis of a 162-bp fragment of the recA gene. Five genospecies were detected: Borrelia afzelii, Borrelia burgdorferi s.s., Borrelia garinii, Borrelia valaisiana, and Borrelia lusitaniae. A heterogeneous distribution was observed within the B. burgdorferi s.l. genospecies. The most prevalent and diverse genospecies found in Switzerland was Borrelia afzelii, which might suggest a rapid evolution of this genospecies. (C) 2004 Federation of European Microbiological Societies. Published by Elsevier B.V. All rights reserved.
- PublicationMétadonnées seulementPhenology of Ixodes ricinus and infection with Borrelia burgdorferi sensu lato along a North- and South-facing altitudinal gradient on Chaumont Mountain, Switzerland(2007)
;Cadenas, Francisca Moran ; ;Jouda, Fatima ; ;Humair, Pierre-François ;Moret, JacquelineQuesting Ixodes ricinus L. ticks were collected monthly from 2003 to 2005 on the north- and south-facing slopes of Chaumont Mountain in Neuchatel, Switzerland, at altitudes varying from 620 to 1,070 in. On the south-facing slope, questing tick density was higher than on the north-facing slope, and it decreased with altitude. Density tended to increase with altitude on the north-facing slope. Saturation deficit values higher than 10 mmHg and lasting for >2 mo were often recorded on the south-facing slope, explaining seasonal patterns of questing tick activity. The overall prevalence of Borrelia burgdorferi sensu lato was 22.4%, and prevalence differed according to exposure and among years. No difference was noticed between nymphs and adults. Four Borrelia species were identified. Mixed infections were detected in 52 ticks, B. garinii and B. valaisiana (n = 21) and B. afzelii and B. burgdorferi s.s. (n = 20) were the most frequent associations observed. The density of infected ticks varied from 3.6 to 78.7 infected nymphs per 1 00 m(2) and from 0.6 to 16.9 infected adults per 100 m(2), both slopes combined. The study on the south-facing slope was a follow-up of a previous study carried out at the same location during 1999-2001. Comparison of climatic data between the two periods showed a marked increase in saturation deficit. Substantial differences in density and phenology of ticks also were observed. At high elevations, ticks were significantly more abundant during the current study. This can be explained by rising temperatures recorded during summer at altitude, reaching values similar to those registered in the first study beneath. At the lowest altitude, adults were significantly less abundant, probably due to long-lasting high saturation deficits that impaired nymphal survival. The density of Borrelia-infected ticks was higher than in the previous study.
- PublicationMétadonnées seulementTransmission 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)
; ;Rouvinez, Evelyne ;Toutoungi, Lina NaimeGodfroid, EdmondEuropean 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.
- PublicationMétadonnées seulementDetection and identification of Borrelia burgdorferi sensu lato genospecies in ticks from three different regions in Slovakia(2007)
;Smetanova, Katarina ;Burri, Caroline ;Perez, David ;Kocianova, ElenaLyme 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.
- PublicationMétadonnées seulementA comparison of two DNA extraction approaches in the detection of Borrelia burgdorferi sensu lato from live Ixodes ricinus ticks by PCR and reverse line blotting(2007)
;Cadenas, Francisca Moran ;Schneider, Helene ; ;Burri, Caroline ;Moret, JacquelineWe tested two approaches to extract Borrelia DNA from live Ixodes ricinus ticks before polymerase chain reaction (PCR) and reverse line blotting (RLB): DNA extraction of one half of the tick after incubation in BSK medium and DNA extraction of the other half of the tick directly, using ammonium hydroxide. Among 2079 ticks, 31.2% (n = 649) were found to be Borrelia-infected by PCR-RLB test using at least one of the DNA extraction methods. Five hundred four ticks (24.2%) were found infected after incubation in BSK and 481 (23.1%) after direct DNA extraction from the tick. The difference was not significant. However, these prevalences were significantly lower when only one method was applied (23.1% and 24.2%) compared to the prevalence obtained by the use of both methods (31.2%). In 313 infected ticks discordant results were obtained, i.e., one half of the tick was found to be infected whereas the other half was uninfected. Among these ticks, B. garinii and B. burgdorferi sensu stricto (ss) were significantly more frequently identified in the half tick incubated in BSK. No significant differences were observed for B. burgdorferi ss, B. valaisiana, and for undetermined Borrelia species.