[Bovine fasciolosis in Switzerland: relevance and control]. / Bovine Fasciolose in der Schweiz: Bedeutung und Bekämpfung.

In Switzerland, bovine fasciolosis is an economically important but often overlooked disease of dairy cows. The intermediate host of Fasciola hepatica in Switzerland is Galba truncatula, an amphibious snail living in humid habitats which are infected by miracidia from recently hatched Fasciola eggs. The definitive hosts include cattle, sheep, goats, horses, and free-living ruminants. Infection of these hosts occur from metacercariae, usually encysted on vegetation. Infection risk depends on the location of the habitat on the farm. There is a lower risk for the intermediate host to become infected on pastures for young stock and dry cows than on pastures for dairy cows. This in turn results in a lower infection risk for young stock and dry cows than for dairy cows. When controlling the disease, epidemiologic factors such as treatment and pasture management strategies should be taken into account. If individual control measures are followed, infection pressure and prevalence in a herd can be significantly reduced. To support veterinarians and farmers in the control of fasciolosis, an interactive map showing potential risk areas for fasciolosis was created on the basis of geographical, meteorological, and biological data of the intermediate host and the free-living parasite stages.

Control of bovine fasciolosis in dairy cattle in Switzerland with emphasis on pasture management.

Thirty-two dairy cattle farms with fasciolosis as an established herd problem were visited and divided into groups according to the location of the habitats of the intermediate host of Fasciola hepatica. The farms were revisited 4-5 years later and those that had followed the recommended measures were compared to those that had not. Egg shedding and seroprevalence was significantly reduced in cows on farms complying with the control recommendations but was not reduced on farms that had not complied.

Estimating the true prevalence of Fasciola hepatica in cattle slaughtered in Switzerland in the absence of an absolute diagnostic test.

A survey of 1,331 cattle presented for slaughter at two abattoirs in Switzerland was used to estimate the true prevalence of Fasciola hepatica infection and the diagnostic parameters of visual meat inspection, coproscopy after sedimentation technique, a commercial ELISA test for specific antibody detection in serum and the post mortem microscopic detection of eggs in bile. Faeces, blood and the gall bladder were taken from most cattle presented for slaughter. In addition, livers that were rejected by the meat inspectors were also dissected to examine for the presence of liver fluke. Bayesian techniques (Markov Chain-Monte Carlo) were used to estimate the diagnostic parameters of each of these procedures and the true prevalence of bovine fasciolosis. The true prevalence of F. hepatica infection was estimated at 18.0% (95% credible intervals 15.9-20.3%). The diagnostic sensitivity of coproscopy, bile examination, antibody ELISA and meat inspection were estimated at 69.0% (57.3-79.7%), 93.4% (88.0-97.5%), 91.7% (87.2-95.2%) and 63.2% (55.6-70.6%), respectively. The diagnostic specificity of the ELISA test was estimated at 93.7% (91.7-95.2%). These results demonstrate that the prevalence of bovine fasciolosis is higher than previously thought due to the low sensitivity of meat inspection. They also demonstrate that traditional coproscopy can be very efficient if there is repeated sampling, resulting in sensitivity of approximately 92%.