title: Changing incidence of bovine babesiosis in Ireland.
abstract: BACKGROUND
  In Ireland bovine babesiosis is caused by the tick-borne blood parasite, Babesia divergens. A survey of veterinary practitioners and farmers in the 1980's revealed an annual incidence of 1.7% associated with considerable economic losses. However, two subsequent surveys in the 1990's indicated a decline in clinical babesiosis. Recent evidence from continental Europe suggests that, probably due to climate change, the distribution of the tick vector of B. divergens, Ixodes ricinus is extending to more northerly regions and higher altitudes. In addition, milder winters are thought to widen the window of tick activity. In order to determine whether any such changes have affected the incidence of bovine babesiosis in Ireland, a questionnaire survey of farmers and veterinarians was carried out and compared with data from previous surveys.
  
  
  RESULTS
  Our survey indicates that while the incidence of clinical disease has continued to decline, cases can occur at any time of year. In contrast to previous surveys, affected farms were the same size as unaffected ones. There was no correlation between disease risk and the presence of deer on the land. Disease severity and mortality rates were increased because many infections were advanced by the time they were detected and treated.
  
  
  CONCLUSIONS
  While the precise reasons for the decline in the incidence of redwater are unknown, changes in agricultural practice are likely to be of importance. A reversal of the trend could be devastating, as vigilance among farmers and veterinarians is flagging and the national herd is losing its protective immunity to disease.
authors.affiliation: UCD School of Veterinary Medicine, University College Dublin, Dublin, Ireland.
authors.forename: Annetta
authors.initials: A
authors.lastname: Zintl
authors.affiliation: UCD School of Veterinary Medicine, University College Dublin, Dublin, Ireland.
authors.forename: Guy
authors.initials: G
authors.lastname: McGrath
authors.affiliation: UCD School of Veterinary Medicine, University College Dublin, Dublin, Ireland.
authors.forename: Luke
authors.initials: L
authors.lastname: O'Grady
authors.affiliation: Central Veterinary Laboratory, Department Agriculture, Food & the Marine, Backweston, Celbridge, Co Kildare, Ireland.
authors.forename: June
authors.initials: J
authors.lastname: Fanning
authors.affiliation: Irish Cattle Breeding Federation, Bandon, Co Cork, Ireland.
authors.forename: Kevin
authors.initials: K
authors.lastname: Downing
authors.affiliation: Growth from Knowledge, GfK Kynetec Ltd, 2 Weston court, Weston, Newbury, Berkshire RG20 8JE, UK.
authors.forename: Denise
authors.initials: D
authors.lastname: Roche
authors.affiliation: Central Veterinary Laboratory, Department Agriculture, Food & the Marine, Backweston, Celbridge, Co Kildare, Ireland.
authors.forename: Mícheál
authors.initials: M
authors.lastname: Casey
authors.affiliation: School of Biology and Environmental Science (Emeritus Professor), University College Dublin, Dublin, Ireland.
authors.forename: Jeremy S
authors.initials: JS
authors.lastname: Gray
keywords: Babesia divergens; Bovine babesiosis; Farm survey; Redwater fever; Tick-borne parasite