Doctorante

Laboratoire d'écologie et évolution des parasites
Institut de biologie
Rue Emile-Argand 11
2000 Neuchâtel

+41 32 718 30 78
dolores.genne@unine.ch

The spirochete bacterium Borrelia afzelii causes Lyme disease in humans. This tick-borne pathogen is transmitted among hosts by the sheep tick Ixodes ricinus. Populations of B. afzelii consist of multiple strains that are often classified according to the highly polymorphic ospC gene that codes for outer surface protein C (OspC). Both vertebrate hosts and the tick vector can carry mixed infections. The purpose of my master thesis project is to study the competition between two ospC strains of B. afzelii, A3 and A10, inside the organs of its rodent host and inside the tick vector. Laboratory mice will be experimentally infected via tick bite with single or double infections of strains A3 and A10. Larval ticks will be allowed to feed on the mice and acquire the spirochete infection. The blood-engorged larval ticks will be allowed to moult into nymphs. I will then check the evolution of the spirochete load of the two strains inside the nymphs over time. I will also study the distribution of both strains inside the mice organs. A strain-specific quantitative PCR will be used to estimate the spirochete loads of each strain in the ticks and the mice organs.