Validation of an interactive map assessing the potential spread of Galba truncatula as intermediate host of Fasciola hepatica in Switzerland.

Bovine fasciolosis, caused by Fasciola hepatica, is widespread in Switzerland. The risk regions were modelled in 2008 by an interactive map, showing the monthly potential risk of transmission of F. hepatica in Switzerland. As this map is based on a mathematical model, the aim of the present study was to evaluate the interactive map by means of a field survey taking different data sources into account. It was found that the interactive map has a sensitivity of 40.7-88.9%, a specificity of 11.4-18.8%, a positive predictive value of 26.7-51.4%, and a negative predictive value of 13.1-83.6%, depending on the source of the data. In conclusion, the grid of the interactive map (100 x 100 m) does not reflect enough detail and the underlying model of the interactive map is lacking transmission data.