SUDDEN DEATHS OF CATTLE ON ALPINE PASTURE S IN SOUTH-EASTERN SWITZERLAND

The aetiology of sudden deaths of cattle in the Kanton Graubunden has been elucidated by a multi-disciplinary approach. Certain small rivers and ponds located in the affected Alpine pastures in the areas of Mis er, Rheinwald and Engadin provide favourable habitats for the growth o f hepatotoxic cyanobacteria, particularly during long periods of hot a nd dry weather As cattle frequently take up water from these sources, the toxins produced by cyanobacteria may lead to lethal poisonings tha t are typically associated with hemorrhagic liver necrosis. The latest reported case of cyanobacteria poisoning of Alpine cattle occurred du ring the summer of 1996. Further animal losses may be avoided by the i mplementation of appropriate pasture management schemes. To identify s ites of potential hazards to human or animal health, we have developed a sensitive screening assay for the detection of cyanobacteria hepato toxins in algae and water samples.