Imported diphyllobothriasis in Switzerland: molecular methods to define a clinical case of Diphyllobothrium infection as Diphyllobothrium dendriticum, August 2010

Following a first clinical case of infection by Diphyllobothrium dendriticum in Switzerland in 2006, we report a second case in the country. The species was identified by molecular methods. In the Swiss, French and Italian subalpine regions, human diphyllobothriasis has seen a comeback since the late 1980's, and Diphyllobothrium latum is usually considered the causative agent of the disease. In addition, several locally acquired and imported clinical infections due to allochthonous Diphyllobothrium species have been documented in the last years. Due to the colonisation potential of these parasites and their probably underestimated presence in the human population, there is a need for discriminating them at the medical laboratory level. Because the morphological characters are very similar among the different taxa, a correct identification requires the use of molecular methods. Molecular identification would improve diagnosis and help monitor the distribution of Diphyllobothrium species in Europe.

The water vapour flux above Switzerland and its role in the August 2005 extreme precipitation and flooding

The water budget approach is applied to an atmospheric box above Switzerland (hereafter referred to as the “Swiss box”) to quantify the atmospheric water vapour flux using ECMWF ERA-Interim reanalyses. The results confirm that the water vapour flux through the Swiss box is highly temporally variable, ranging from 1 to 5 · 107 kg/s during settled anticyclonic weather, but increasing in size by a factor of ten or more during high speed currents of water vapour. Overall, Switzerland and the Swiss box “import” more water vapour than it “exports”, but the amount gained remains only a small fraction (1% to 5%) of the total available water vapour passing by. High inward water vapour fluxes are not necessarily linked to high precipitation episodes. The water vapour flux during the August 2005 floods, which caused severe damage in central Switzerland, is examined and an assessment is made of the computed water vapour fluxes compared to high spatio-temporal rain gauge and radar observations. About 25% of the incoming water vapour flux was stored in Switzerland. The computed water vapour fluxes from ECMWF data compare well with the mean rain gauge observations and the combined rain-gauge radar precipitation products.