Campylobacter infections are a major public health concern and in the past few years, haveemerged as a leading cause of bacterial gastroenteritis in Luxembourg as well as in the otherEU Member States. Most cases are sporadic and the source of contamination is rarely known.Our previous FNR-funded project EPIFOOD suggested that while the primary route oftransmission was still food-borne, environmental routes might be more important thanpreviously thought. In particular, for young children, representing a the large fraction of humancases, the transmission routes are also likely to be environmental rather than food-bornebecause of with their limited diets and their high rate of hand-mouth behavior. In Luxembourg,30 % of the reported cases result from children under 10 year-old. By using case-controlmethodology, water-related factors have been significantly associated with the illness in infants.Furthermore, some water-borne outbreaks have been also reported in the literature. In thesame field, amoebae were recently identified as a potential reservoir for Campylobacter jejuni inaquatic niches. The relative contribution of the latter to human infections remains to beelucidated.Another major area of investigation is related to the role of insects (in particular house flies) inthe spread of Campylobacter. The involvement of cattle in the contamination cycle of thepathogen via environmental routes is increasingly recognized and flies could be an activevector in the transmission pathways to human. This hypothesis is mainly supported by closecorrelation between seasonal peak in human cases and Musca domestica larval developmenttime.The objective of our project is to investigate the likely contribution of various environmentalreservoirs and vehicles to human campylobacteriosis in Luxembourg.A first major focus will be on detecting and culturing Campylobacter in untreated surface watersuch as private wells, recreational surface waters, fishing areas and streams. In order toperform a sampling that is representative of the studied water bodies, theultrafiltration/ultracentrifugation protocol successfully developed in the FNR-funded projectKAWA will be applied to concentrate Campylobacter from volumes higher than a cubic meter.As a way to optimize the recovery of bacteria, we would propose to assess the recentlydescribed method of protozoan vectors to enhance the prospects of culturing these fastidiousbacteria from aquatic environments. A second major focus will be put on investigating the roleof house flies by setting up a sampling framework in different socio-geographic areas wherecontamination is likely to occur including farms, garbage tips. Finally, a third focus will be tofurther document risk factors of campylobacteriosis in Luxembourg with a web- and paperbasedsurvey to collect important epidemiological data from patients including recent history oftravel, contact with pets or farms animals and other environmental exposure.State of the art genotyping methods will be implemented, partly by technological transfer of theexpertise gained from the results of the previously FNR-funded EPIFOOD project. Comparisonof molecular fingerprints of isolates collected from the environment and from patients will beconducted to identify epidemiological links.The project seeks to build upon the expertise gained during previous FNR-funded projectsKAWA & EPIFOOD combining environmental microbiology and epidemiology. It will strengthencompetences in Campylobacter detection, typing and control through the development of thenecessary laboratory tools and databases. Furthermore it will help to gain new methodologicalexpertise in environmental bacteriology.