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Aeschlimann, André

Nom
Aeschlimann, André
Affiliation principale
Fonction
Professeur honoraire
Email
audrey.aeschlimann@unine.ch
Identifiants
https://libra.unine.ch/handle/123456789/348

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  • Publication
    Métadonnées seulement
    Longitudinal study of Lyme borreliosis in a high risk population in Switzerland
    (1998)
    Zhioua, Elyes
    ;
    Gern, Lise 
    ;
    Aeschlimann, André 
    ;
    Sauvain, Marie-Josephe
    ;
    Van der Linden, Sjef
    ;
    Fahrer, Heinz
    Orienteers 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.
  • Publication
    Accès libre
    Biology of Ixodes (Pholeoixodes) hexagonus under laboratory conditions. Part I. Immature stages
    (1993)
    Toutoungi, L. N.
    ;
    Gern, Lise 
    ;
    Aeschlimann, André 
    A rearing method for Ixodes (Pholeoixodes) hexagonus, the hedgehog tick, was established which enabled the life cycle of immature stages to be studied under laboratory conditions. Larvae were fed on Swiss mice and nymphs on the cars of New Zealand rabbits. The feeding time of the larvae and nymphs on both hosts was 4–17 days. Larvae moulted to nymphs 15–21 days after detachment from mice. The premoulting period was 13–26 days for newly emerged males and 15–27 days for females. Engorged nymphs which developed into males weighed less (5.64±0.91 mg) than those that developed into females (6.019±88mg). The sex ratio (male: female) under laboratory conditions was 1:1.13.
  • Publication
    Accès libre
    Ixodes ricinus immatures on birds in a focus of Lyme borreliosis
    (1993)
    Humair, Pierre-François
    ;
    Turrian N.
    ;
    Aeschlimann, André 
    ;
    Gern, Lise 
    The infestation of birds by immature Ixodes ricinus was studied during 6 months in a Swiss woodland, where Lyme borreliosis is endemic. Thirteen passerine species were found to be parasitized by /. ricinus subadults and specially Turdus merula, T, philomelos and Erithacus rubecula. Overall, 300 larvae and 162 nymphs were collected on 95 avian hosts. Prevalence of infestation of nymphs on birds was higher in spring; larvae peaked in summer. The infection of birds by Borrelia burgdorferi was also studied using blood cultivation and examinations of ticks. Motionless spirochetes were isolated from two E. rubecula. Infected ticks were removed from five species of passerines, and mainly three species of Turdidae (T. merula, T. phllomelos and E. rubecula}. Infection rate of larvae and nymphs by spirochetes averaged 16.3% and 21.7%, respectively. These percentages, compared to the infection rate of questing ticks collected through dragging, suggest that some Turdidae may play a role as amplifying hosts for spirochetes in the focus.
  • Publication
    Accès libre
    The Ecology of Lyme Borreliosis in Europe
    (1992)
    Gern, Lise 
    ;
    Burgdorfer, Willy
    ;
    Aeschlimann, André 
    ;
    Krampitz, H. E.
  • Publication
    Accès libre
    Comparative considerations on the epidemiology of Lyme borreliosis and tick-borne encephalitis in Switzerland
    (1991)
    Gern, Lise 
    ;
    de Marval, F.
    ;
    Aeschlimann, André 
    In Switzerland, the spirochete Borrelia burgdorferi and tick-borne encephalitis virus infect the human population. These infections may cause serious pathogenic effects to men and domestic animals. The tick Ixodes ricinus is the vector of both microorganisms. The distribution of the virus is concentrated in small foci scattered in some regions. In these areas, the infection occurs in less than 1 % of the ticks. The distribution of the spirochete is larger and more regular in the Swiss territory and B. burgdorferi is present in 5 to 50 % of/, ricinus. It is the aim of this paper to try to explain how both types of foci occur, considering especially the problem of small mammals as reservoirs for the bacterium and the virus.
  • Publication
    Accès libre
    The peritrophic membrane of Ixodes ricinus
    (1991)
    Zhu, Z.
    ;
    Gern, Lise 
    ;
    Aeschlimann, André 
    A peritrophic membrane was found in all three stages of Ixodes ricinus at no later than 18 h after their placement on rabbits. It was found to remain intact until at least 11, 30 and 10 days after repletion in larvae, nymphs and females, respectively. In blood-feeding I. ricinus, the peritrophic membrane is an uneven single layer with a thickness of about 0.03–0.48 μm in larvae, 0.03–0.79 μm in nymphs and 0.04–0.93 μm in females. It covers the whole surface of the midgut epithelium at a distance of about 0.2–0.8 μm. After repletion, the peritrophic membrane becomes thicker and thicker and more and more winding and simultaneously becomes multi-layered mainly in its arched parts. The distance between the peritrophic membrane and the midgut epithelium increases considerably and in the arched parts can reach as much as about 13 and 16 μm in metamorphosing larvae and nymphs, respectively and 25 μm in ovipositing females.
  • Publication
    Accès libre
    Ixodes (Pholeoixodes) hexagonus, an efficient vector of Borrelia burgdorferi in the laboratory
    (1991)
    Gern, Lise 
    ;
    Toutoungi, L. N.
    ;
    Hu, Chang Min
    ;
    Aeschlimann, André 
    Borrelia burgdorferi Johnson et al. was first isolated from the midgut of Ixodes dammini Spielman et al. in the U.S.A. and from the midgut of Lricinus (L.) in Europe. I.ricinus was considered to be the only tick vector of this borrelia, in Europe, until I.hexagonus Leach, the hedgehog tick, was found to harbour spirochaetes. This paper reports an evaluation of the vector competence of I. hexagonus for the spirochaete B. burgdorferi. Transovarial and trans-stadial survival were demonstrated and the spirochaete was transmitted to laboratory mice via the bites of trans-stadially infected I.hexagonus females.
  • Publication
    Accès libre
    The Prevalence and Incidence of Clinical and Asymptomatic Lyme Borreliosis in a Population at Risk
    (1991)
    Fahrer, Heinz
    ;
    van der Linden, Sjef M.
    ;
    Sauvain, Marie-Josephe
    ;
    Gern, Lise 
    ;
    Zhioua, Elyes
    ;
    Aeschlimann, André 
    A past history of clinical Lyme borreliosis and the 6-month incidence of clinical and asymptomatic Lyme borreliosis was studied prospectively in a high-risk population. In the spring, blood samples were drawn from 950 Swiss orienteers, who also answered a questionnaire. IgG anti-Borrelia burgdorferi antibodies were detected by ELISA. Positive IgG antibodies were seen in 248 (26.1%), in contrast to 3.9%-6.0% in two groups of controls (n = 101). Of the orienteers, 1.9%-3.1% had a past history of definite or probable clinical Lyme borreliosis. Six months later a second blood sample was obtained from 755 participants, 558 (73.9%) of whom were seronegative initially; 45 (8.1%) had seroconverted from negative to positive. Only 1 (2.2%) developed clinical Lyme borreliosis. Among all participants, the 6-month incidence of clinical Lyme borreliosis was 0.8% (6/755) but was much higher (8.1%) for asymptomatic seroconversion (45/558). In conclusion, positive Lyme serology was common in Swiss orienteers, but clinical disease occurred infrequently.
  • Publication
    Accès libre
    A propos du genre Pholeoixodes, parasite des carnivores en Suisse
    (1991)
    Toutoungi, L. N.
    ;
    Gern, Lise 
    ;
    Aeschlimann, André 
    ;
    Debrot, S.
    Une étude faunistique a été entreprise en Suisse sur trois espèces de tiques pholéophiles, parasites des carnivores sauvages. Il s'agit de Ph. hexagonus, Ph. canisuga, Ph. rugicollis.
    Nous avons concentré nos recherches sur la repartition géographique, les hôtes et la nature de l'infestation.
    Le matériel provient de la collection AESCHLIMANN et DEBROT du Musée Zoologique de Lausanne, ainsi que des tiques prélevées récemment sur des carnivores par le Centre de la rage à Berne.
    La répartition de Ph. hexagonus recouvre la Suisse entière, au Nord comme au Sud des Alpes. On l'observe en altitude jusqu'à 1 380 m. Cette tique a été récoltée sur 15 espèces animales. Elle parasite surtout les renards et tous les Mustélidés, mais elle a également été souvent observée sur des animaux domestiques tels que le chat et le chien.
    Ph. canisuga apparaît fréquemment sur le Plateau Suisse et dans le Jura. Cette espèce parasite essentiellement le renard et le blaireau.
    L'existence en Suisse de Ph. rugicollis, espèce apparemment rare, est démontrée sur 2 fouines et un chat.
    58 % des renards examinés et 87 % des Mustélidés sont infestés par une seule espèce de tique. Par contre 42 % de ces renards présentent des infestations mixtes avec plusieurs espèces de tiques, dans 18% des cas il s'agit de Ph. hexagonus et I. Ricinus., A study concerning 3 tick species ectoparasitic on camivora : Pholeoixodes hexagonus. Ph. canisuga and Ph. rugicollis was conducted in Switzerland.
    Our research focused on the geographical distribution of these ticks and their hosts. The material was supplied from AESCHLIMANN'S collection deposited in the Zoological Museum in Lausanne and from the Rabies Center in Bern.
    Ph. hexagonus is spread all over the country up to 1 380 m. It was collected from 15 animal species, especially from foxes and Mustelidae. Domestic animals like dogs and cats were also found infested.
    Ph. canisuga is widespread on the Swiss Plateau and in the Jura up to 900 m. It was mainly collected from foxes and badgers.
    Ph. Rugicollis seems to be rare in Switzerland where it was recorded only three times, twice on a stone marten and once on a cat.
    A monospecific infestation was observed in respectively 58 % and 87 % of the infested foxes and Mustelidae. Ph. hexagonus and I. ricinus were found simulta- neously on the same host on 18 % of the foxes.
  • Publication
    Accès libre
    Borrelia burgdorferi in ticks of the Canton Tessin (Switzerland)
    (1990)
    Miserez, V.
    ;
    Gern, Lise 
    ;
    Aeschlimann, André 
    In the northern Alps it is hard to find an Ixodes ricinus population which does not harbour Borrelia burgdorferi. The infection rates range from 5 to 34% for adults and nymphs to 3.1% for larvae. This study shows that the infection rates on the southern side of the Alps are similar, at 25% for adults, 36.2% for nymphs and 3.2% for larvae. With respect to tick species other than I. ricinus, we did not succeed in finding any spirochetes in Dermacentor marginatus, Haemaphysalis punctata, Ixodes hexagonus, Rhipicephalus sanguineus.