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Université de Neuchâtel

Ixodid ticks avoid contact with liquid water

Kröber, Thomas ; Guerin, Patrick M.

In: The Journal of Experimental Biology, 1999, vol. 202, no. 14, p. 1887-1883

Larvae of the cattle tick Boophilus microplus and all life stages of the European sheep tick Ixodes ricinus avoid walking on a wet membrane surface surrounding a dry patch. Of 170 reactions made at a border with liquid water by 22 B. microplus larvae, 40% consisted of immediate turns to the opposite side to bring all the legs back onto a dry patch, 41% were walks along the border, during which...

Université de Neuchâtel

The Tick Blood Meal: From a Living Animalor from a Silicone Membrane ?

Kröber, Thomas ; Guerin, Patrick M.

In: Altex, 2007, vol. 24, p. 39-41

An artificial feeding unit with a reinforced silicone membrane to replace host skin provides ticks with a perch over blood with a tick attachment rate of 75-100%. Some 5 mg of an acaricide like fipronil is sufficient to establish survival curves over different doses down to ppb levels in blood. This in vitro feeding assay for hard ticks is more advantageous than in vivotrials on animals.

Université de Neuchâtel

Ixodes ricinus : vector of a hitherto undescribed spotted fever group agent in Switzerland

Burgdorfer, Willy ; Barbour, Alan G. ; Hayes, Stanley F. ; Péter, Olivier ; Aeschlimann, André

In: Acta Tropica, 1979, vol. 36, p. 357-367

A tick/rickettsial survey in various parts of Switzerland revealed the presence of a new, hitherto undescribed spotted fever group rickettsia ("Swiss agent") in up to 11.7% of I ricinus collected off vegetation. Infection in ticks was found to be generalized with rickettsiae developing intracellularly and occasionally also intranuclearly. As a result of massive growth in ovarial tissues,...

Université de Neuchâtel

Contact chemostimuli in the mating behaviour of the cattle tick, Boophilus microplus

de Bruyne, Marien ; Guerin, Patrick M.

In: Archives of Insect Biochemistry and Physiology, 1999, vol. 39, no. 2, p. 65-80

Mating of the cattle tick Boophilus microplus is mediated by chemical stimuli on the cuticle of females. Males are arrested on the dorsum of females attached to the host, frequently sample the substrate, and then tip-over to the ventrally located gonopore. These behaviours are also observed in vitro when males are placed on a small glass bead treated with a female extract. Time spent and...

Université de Neuchâtel

The Dynamics of an Avoidance Behavior by Ixodid Ticks to Liquid Water

Kröber, Thomas ; Guerin, Patrick M.

In: Journal of Insect Behavior, 2000, vol. 13, no. 3, p. 397-420

Life stages of different tick species avoid walking on a wet surface surrounding a dry patch by systematically returning to the dry each time they contact the wet surface beyond the border with the tip of a first leg tarsus. Sequential analysis of the border behaviors shows that repetitive contact with the water increases the probability of walks astride the border. Ticks accept this unilateral...

Université de Neuchâtel

In vitro assays for repellents and deterrents for ticks: differing effects of products when tested with attractant or arrestment stimuli

McMahon, Conor ; Kröber, Thomas ; Guerin, Patrick M.

In: Medical and Veterinary Entomology, 2003, vol. 17, no. 4, p. 370-378

Most in vivo and in vitro tests with repellents or deterrents against ticks have not considered which sensory channel is being targeted. We have recorded the responses of two hard tick species (Acari: Ixodidae) in vitro to determine if such products can disrupt the perception of an attractant in a repellent assay or the perception of an arrestment stimulus in a deterrent...

Université de Neuchâtel

Identification of an Ixodes ricinus salivary gland fraction through its ability to stimulate CD4 T cells present in BALB/c mice lymph nodes draining the tick fixation site

Ganapamo, F. ; Rutti, Bernard ; Brossard, Michel

In: Parasitoloty, 1997, vol. 115, no. 1, p. 91-96

BALB/c mice infested with larvae or nymphs of Ixodes ricinus develop in their lymph nodes a T cell-specific immune response triggered by salivary gland soluble antigens (SGA). SGA are apparently conserved in the 3 biological stages of I. ricinus ticks and are species specific. SGA derived from partially fed females I. ricinus stimulate lymph node T cells from mice infested...

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....