Pyrrolizidine alkaloids belong to a class of phytotoxins which are present in more than 6000 plant species. The disease seneciosis in farm animals represents the severe
poisoning by
pyrrolizidine alkaloids from plants of the genus Senecio. This form of
poisoning has been known since the end of the 19th century in Germany, the USA, Canada and New Zealand, and is mainly caused by Senecio jacobaea and related Senecio spp. in farm animals, including poultry. Animal
poisoning by
pyrrolizidine alkaloids is of worldwide importance. In Germany
poisoning of horses and cattle by Senecio jacobaea, which was earlier named Schweinsberg disease, is of renewed relevance for veterinary medicine. The disease occurs almost entirely as a consequence of chronic
poisoning and in general ends fatally. The ultimate cause is the formation of toxic metabolites of
pyrrolizidine alkaloids in the liver, and their covalent binding to
nucleic acids and
proteins leading to
liver cirrhosis. Because many
pyrrolizidine alkaloids possess mutagenic, and a few also carcinogenic properties, European and international authorities are concerned about possible residue levels in food of animal origin. The review addresses in its first part several aspects, being the occurrence, the chemistry, and the toxicology of
pyrrolizidine alkaloids as well as animal intoxications by poisonous plants. In the second part (46) clinical characteristics of animal seneciosis, the therapeutic interventions, the significant species differences and a critical assessment of so-called nontoxic amounts of Senecio plants in animal fodder with reference to cumulative lethal toxin doses are presented.