Chapter 33 - Poisonous plants: biomarkers for diagnosis

Abstract

Research on poisonous plants in the USA began over 100 years ago and resulted from livestock poisonings by locoweeds, larkspurs, lupines, hemlocks, death camas, selenium-accumulating forages, and other plants. Poisonings soon began to occur in livestock as the migration westward resulted in overgrazing and exposure of livestock to unfamiliar rangelands and toxic forbs. Research was initiated by the U.S. government in an attempt to mitigate losses and to further encourage settlement of the west. Much of this early research was based on identifying the offending plant and observational studies to describe the poisonings in livestock. Over the last 50 years, advances in technology and research have resulted in identification of thousands of phytochemicals, characterization of their biological effects, and development of management methods or treatments to mitigate poisoning. Identification of biomarkers to improve diagnosis of plant toxicoses has always been an important need for clinicians, diagnostic labs, and scientists. However, few biomarkers specific for plant toxicoses exist. At the USDA Poisonous Plant Research Lab, one area of research emphasis is development of biomarkers specific for poisonous plant diagnosis. This includes chemical detection of toxins in specific tissues, histopathological description, and biochemical changes associated with specific poisonous plant toxicoses. In this chapter, some of the most important poisonous plants and their toxins that affect livestock are reviewed, and the current status of biomarker development is discussed.