title: Epidemiology and risk factors for exposure to gastrointestinal nematodes in dairy herds in northwestern Europe.
abstract: In this survey, the epidemiology of gastrointestinal (GI) nematodes in dairy herds in five northwestern European countries was studied using a standardized Ostertagia ostertagi ELISA applied on bulk-tank milk, and a common questionnaire. The levels of exposure to GI nematodes were high in Belgium, the UK and Ireland, intermediate in Germany and low in Sweden, with a mean (95% confidence interval) ELISA result (ODR) of 0.83 (0.82-0.84) in Belgium, 0.82 (0.79-0.84) in the UK and 0.80 (0.78-0.83) in Ireland; significantly higher than the mean ODR of 0.66 (0.65-0.68) in Germany and 0.52 (0.51-0.53) in Sweden. Taking into account previous literature, these regional differences are likely to be systematic. Regional variations in exposure were significantly explained by differences in management (grazing time per day, mowing, the months of turnout, housing and anthelmintic treatment). However, after controlling for these factors, significant regional differences in levels of exposure remained, suggesting an importance for climate (temperature, rainfall) and unmeasured management factors. This study emphasizes that GI nematode-induced production losses should be considered on a large percentage of northwest European dairy herds. Proposals are made for the development of region-specific monitoring and control strategies. Further advances in this area are likely to come from intervention studies that investigate the feasibility of control measures and from studies on the potential effects of climatic conditions on shifts in levels of exposure between years and regions.
authors.affiliation: Department of Virology, Parasitology and Immunology, Faculty of Veterinary Medicine, Ghent University, Salisburylaan 133, 9820 Merelbeke, Belgium. sita.bennema@ugent.be
authors.forename: Sita C
authors.initials: SC
authors.lastname: Bennema
authors.forename: Jozef
authors.initials: J
authors.lastname: Vercruysse
authors.forename: Eric
authors.initials: E
authors.lastname: Morgan
authors.forename: Kathryn
authors.initials: K
authors.lastname: Stafford
authors.forename: Johan
authors.initials: J
authors.lastname: Höglund
authors.forename: Janina
authors.initials: J
authors.lastname: Demeler
authors.forename: Georg
authors.initials: G
authors.lastname: von Samson-Himmelstjerna
authors.forename: Johannes
authors.initials: J
authors.lastname: Charlier
mesh_terms: D000822:Animal Husbandry / Q000379:methods; D000818:Animals; D002417:Cattle; D002418:Cattle Diseases / Q000453:epidemiology / Q000469:parasitology*; D002980:Climate; D005060:Europe; D005260:Female; D005767:Gastrointestinal Diseases / Q000453:epidemiology / Q000469:parasitology / Q000662:veterinary*; D016014:Linear Models; D008892:Milk / Q000469:parasitology*; D015999:Multivariate Analysis; D009348:Nematoda / Q000302:isolation & purification*; D009349:Nematode Infections / Q000453:epidemiology / Q000469:parasitology / Q000662:veterinary*; D012307:Risk Factors; D012621:Seasons; D011795:Surveys and Questionnaires