Changing incidence of bovine babesiosis in Ireland

Abstract

BackgroundIn 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.ResultsOur 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.ConclusionWhile 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.

Distribution and prevalence of ticks and tick-borne disease on sheep and cattle farms in Great Britain

“…In 2006, Barton et al [63] also found a high reported prevalence of redwater in a survey of cattle farms in the south-west, with 66% of farms reporting ticks also reporting redwater. Redwater is endemic to the UK, but clinical cases are generally only apparent when there is a breakdown in population immunity [9]. Cases may be more prevalent in the southwest because of less consistent contact between cattle and ticks, resulting in occasions where cattle are unexposed at a younger age, but are then later grazed on tick infested pastures.…”

Emergence and Epidemiology of Bovine Babesiosis Due to Babesia divergens on a Northern German Beef Production Farm

“…Mucous membranes may be pale or jaundiced, and haemoglobinuria occurs at the peak of the haemolytic crisis (8,11). Spontaneous recoveries are rare, thus, case fatality rates are mainly influenced by the speed of diagnosis and treatment (12).…”

“…Several studies have indicated a change in B. divergens epidemiology in Europe during the last decades. A marked decrease in disease incidence has been reported from Norway (13), Hungary (14), and Ireland (12). A reduction in cattle density, changes in pasturing practices and improvement of pastures have been proposed as causative factors for this decline (12)(13)(14).…”

“…A marked decrease in disease incidence has been reported from Norway (13), Hungary (14), and Ireland (12). A reduction in cattle density, changes in pasturing practices and improvement of pastures have been proposed as causative factors for this decline (12)(13)(14). In Ireland, where bovine babesiosis was once a disease with considerable economic impact, incidence has declined considerably since the 1980s, and, furthermore, the annual pattern of disease outbreaks has changed (12).…”

Knockout of Babesia bovis rad51 ortholog and its complementation by expression from the BbACc3 artificial chromosome platform

“…With increasing human population density and environmental encroachment, as well as climate change, many zoonotic diseases are emerging and/or expanding in range, including babesiosis [38–40]. It is thus important that we understand well the biology of these parasites, and prepare to defend against their expansion.…”