Université de Neuchâtel

Effects of acquired immunity on co-feeding and systemic transmission of the Lyme disease bacterium, "Borrelia afzelii"

Jacquet, Maxime ; Voordouw, Maarten (Dir.)

Thèse de doctorat : Université de Neuchâtel, 2015.

La borréliose de Lyme est une zoonose transmise par les tiques. Les bactéries qui en sont la cause, des spirochètes, se trouvent principalement chez des hôtes réservoirs sauvages tels que des rongeurs ou des petits oiseaux terrricoles. Borrelia afzelii est l’un des pathogènes responsables de la borréliose de Lyme les plus importants en Europe et est transmis par la tique du mouton...

Université de Neuchâtel

Do the level of energy reserves, hydration status and Borrelia infection influence walking by Ixodes ricinus (Acari: Ixodidae) ticks?

Herrmann, Coralie ; Gern, Lise

In: Parasitology, 2011, vol. 139, no. 3, p. 330-337

Ixodes ricinus horizontal movement within a humidity gradient and the influence of infection by Borrelia burgdorferi sensu lato (s.l.) on tick walking were investigated. Nymphs were placed within an arena containing a humidity gradient ranging from 45 to 95% relative humidity (RH). After 1 h of acclimation at 70% RHticks were released so that they could either stay, or walk...

Université de Neuchâtel

Dynamique de transmission de 'Borrelia afzelii' par 'Ixodes ricinus' : comparaisons entre groupes ospC

Tonetti, Nicolas ; Gern, Lise (Dir.)

Thèse de doctorat : Université de Neuchâtel, 2012.

La protéine de surface C (OspC) de Borrelia burgdorferi sensu lato (sl) est impliquée dans de nombreux mécanismes participant à la dissémination de l'agent pathogène chez son hôte. La grande diversité du gène ospC a permis une classification des différents allèles en groupes, laissant apparaître un lien entre l'invasivité de la bactérie chez l'Homme et les différents...

Université de Neuchâtel

Agents pathogènes d'importance médicale et vétérinaire chez 'Ixodes ricinus' en Suisse : infections et co-infections chez les tiques en quête et les tiques d'oiseaux

Lommano, Elena ; Gern, Lise (Dir.)

Thèse de doctorat : Université de Neuchâtel, 2012.

Dans les régions tempérées de l’hémisphère nord, les tiques représentent le premier vecteur d’agents infectieux d’importance médicale et vétérinaire. Parmi elles, Ixodes ricinus, abondante en Europe, transmet bon nombre de microorganismes aux Hommes et aux animaux, aussi bien des bactéries, des virus, que des protozoaires, pour la plupart responsables de zoonoses...

Université de Neuchâtel

Investigations on the Mode and Dynamics of Transmission and Infectivity of Borrelia burgdorferi Sensu Stricto and Borrelia afzelii in Ixodes ricinus Ticks

Crippa, Mara ; Rais, Olivier ; Gern, Lise

In: Vector Borne Zoonotic Diseases, 2002, vol. 2, no. 1, p. 3-9

Borrelia burgdorferi sensu lato (sl), the agent of Lyme disease, is transmitted to the host during the blood meal of Ixodes ticks. In most unfed ticks, spirochetes are present in the midgut and migrate during blood feeding to the salivary glands, from which they are transmitted to the host via saliva. In the present study, the efficiency of Ixodes ricinus ticks to transmit...

Université de Neuchâtel

Density of questing Ixodes ricinus nymphs and adults infected by Borrelia burgdorferi sensu lato in Switzerland: spatio-temporal pattern at a regional scale

Jouda, Fatima ; Perret, Jean-Luc ; Gern, Lise

In: Vector Borne Zoonotic Diseases, 2004, vol. 4, no. 1, p. 23-32

Lyme 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...

Université de Neuchâtel

Assessment of intraspecific mtDNA variability of European Ixodes ricinus sensu stricto (Acari: Ixodidae)

Casati, Simona ; Bernasconi, Marco V. ; Gern, Lise ; Piffaretti, Jean-Claude

In: Infection, Genetics and Evolution, 2008, vol. 8, no. 2, p. 152-158

The Ixodes ricinus complex is composed of 14 species distributed worldwide. Some members of this complex are involved in the transmission of a number of diseases to animals and humans, in particular Lyme borreliosis, tick-borne encephalitis, ehrlichiosis and babesiosis. While the phylogenetic relationships between species of the I. ricinus complex have been investigated in the past,...

Université de Neuchâtel

Splenic dendritic cells pulsed with Ixodes ricinus tick saliva prime naive CD4+T to induce Th2 cell differentiation in vitro and in vivo

Mejri, Naceur ; Brossard, Michel

In: International Immunology, 2007, vol. 19, no. 4, p. 535-543

Dendritic cells (DCs) are the most potent antigen-presenting cells (APCs) in priming naive T cells. Using an in vitro priming system, we show that DCs incubated with Ixodes ricinus tick saliva initiate the Th2 differentiation of CD4+T cells. As determined with reverse transcription–PCR, the expression of IL-4 mRNA by these cells is higher than IFN-γ mRNA....

Université de Neuchâtel

Diversity within Borrelia burgdorferi sensu lato genospecies in Switzerland by recA gene sequence

Casati, Simona ; Bernasconi, Marco V. ; Gern, Lise ; Piffaretti, Jean-Claude

In: FEMS Microbiology Letters, 2004, vol. 238, p. 115-123

A 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...