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Eco-épidémiologie de la tique Ixodes ricinus et des pathogènes qu'elle transmet en Suisse
Titre du projet
Eco-épidémiologie de la tique Ixodes ricinus et des pathogènes qu'elle transmet en Suisse
Description
Lyme borreliosis (LB) and Tick-borne encephalitis (TBE), both due to the bites of the tick Ixodes ricinus, are significant vector-borne diseases in humans in Switzerland. Risk of acquiring these diseases is primarily related to the frequency of contacts with infected ticks. Human activity is one of the factors influencing these contacts. However spatial and temporal variations of tick density are also important. Global climate change is suspected in having potential effects on distributions of tick-borne diseases. Increase in temperature may result in the extension of habitats suitable for ticks into higher altitudes. However assessing the relative importance of climate changes needs solid long-term data on ticks, which can then be statistically analysed and tested on biological models. Therefore, we will continue our study (1996-today) on the seasonal tick activity in relation with climatic data and on infection with Borrelia and we will statistically analyse these datasets. This should help to differentiate short-term fluctuations from long-term trends. These data will also be used to test and perfect an I. ricinus tick population model. TBE is a neurological disease due to a flavivirus. Recently, an increase of TBE cases and an emergence of new TBE foci were observed in Switzerland. We will study the role of migratory and local birds in the transport and the maintenance of TBE virus. We also intend to analyse the ticks for other tick-borne pathogens. LB is a systemic disease due to Borrelia burgdorferi and up to seven Borrelia species can infect the tick populations in Switzerland. The ospC gene of Borrelia is highly variable within each Borrelia species and can be used to define groups. A few ospC groups cause invasive forms of the disease in humans, other groups are not invasive or non pathogenic to humans. We are interested in studying the development of the Borrelia infection in the tick and the transmission processes to the host and from the host in relation with ospC groups. Recent studies suggested that Borrelia infection in I. ricinus ticks might also play a role in geographical dispersal of ticks. We will study population genetic in the context of tick dispersion in relation with their infection by Borrelia species. These projects should contribute to a better understanding of the eco-epidemiology of I. ricinus and tick-borne pathogens in relation with human risk to acquire the diseases.
Chercheur principal
Statut
Completed
Date de début
1 Octobre 2009
Date de fin
30 Septembre 2012
Organisations
Identifiant interne
15159
identifiant