title: Determining the Prevalence and Seasonality of Fasciola hepatica in Pasture-based Dairy herds in Ireland using a Bulk Tank Milk ELISA.
abstract: BACKGROUND
  Fasciola hepatica is a helminth parasite of global importance in livestock, with major economic impact. However information on F. hepatica infections in Irish pasture-based dairy herds is limited. Therefore this study was conducted in order to determine the prevalence, seasonality and management factors associated with F. hepatica. A total of 319 Irish dairy herds were selected for this study. Bulk tank milk (BTM) samples were collected from 290 dairy farms on a quarter year basis, while from a further 29 dairy farms BTM samples were collected on a monthly basis to provide a more detailed pattern of F. hepatica exposure in Irish herds. BTM samples were analysed using a commercially available F. hepatica antibody detection ELISA. Furthermore, within-herd prevalence of F. hepatica was assessed in a subset of these 29 herds (n = 17); both individual serum samples and bulk tank milk samples were collected.
  
  
  RESULTS
  A within-herd prevalence of ≤ 50 % was found for herds with negative bulk tank milk samples. The mean prevalence of the 290 study herds was 75.4 % (Range 52 %-75.1 %), with the highest prevalence being observed in November (75.1 %). The seasonal pattern of F. hepatica shows elevated antibodies as the grazing season progressed, reaching a peak in January. A significant association was found between F. hepatica and age at first calving.
  
  
  CONCLUSIONS
  This study demonstrates that F. hepatica is present in a large proportion of Irish dairy herds and provides a basis on which control practices, particularly in adult dairy cows, can be reviewed.
authors.affiliation: Animal and Bioscience Research Department, Animal & Grassland Research and Innovation Centre, Teagasc, Moorepark, Fermoy, Co. Cork, Republic of Ireland.
authors.forename: Yris
authors.initials: Y
authors.lastname: Bloemhoff
authors.affiliation: Merial, 29 Avenue Tony Garnier, 69007 Lyon, France.
authors.forename: Andrew
authors.initials: A
authors.lastname: Forbes
authors.affiliation: Food Safety Department, Food Research Centre, Ashtown, Teagasc, Dublin 15, Republic of Ireland.
authors.forename: Martin
authors.initials: M
authors.lastname: Danaher
authors.affiliation: Animal and Grassland Research and Innovation Centre, Teagasc, Athenry, Co, Galway, Republic of Ireland.
authors.forename: Barbara
authors.initials: B
authors.lastname: Good
authors.affiliation: School of Biological Sciences, University of Bristol, Woodland Road, Bristol, BS8 1UG UK.
authors.forename: Eric
authors.initials: E
authors.lastname: Morgan
authors.affiliation: School of Veterinary Medicine, University College Dublin, Belfield, Dublin 4, Republic of Ireland.
authors.forename: Grace
authors.initials: G
authors.lastname: Mulcahy
authors.affiliation: School of Veterinary Medicine, University College Dublin, Belfield, Dublin 4, Republic of Ireland.
authors.forename: Mary
authors.initials: M
authors.lastname: Sekiya
authors.affiliation: Animal and Bioscience Research Department, Animal & Grassland Research and Innovation Centre, Teagasc, Moorepark, Fermoy, Co. Cork, Republic of Ireland.
authors.forename: Ríona
authors.initials: R
authors.lastname: Sayers
keywords: Dairy cows; ELISA; Epidemiology; Fasciola hepatica; Seasonality