In Brazil, one of the most important groups of toxic plants is that which causes sudden death associated with exercise, which comprises plants of the Rubiaceae, Bignoniaceae, and Malpighiaceae families. The nomenclature of some plants of the Malpighiaceae family, previously identified as Mascagnia, was modified to Amorimia. Among the species of toxic Amorimia in Brazil there are Amorimia amazonica, Amorimia exotropica, Amorimia pubiflora, Amorimia rigida, Amorimia septentrionalis, Amorimia sp. (Mascagnia rigida complex; Mascagnia aff. rigida), and a plant identified as Mascagnia sepium, which is probably Amorimia amazonica. In these species the toxic compound is sodium monofluoroacetate (MFA). Another toxic species, Amorimia concinna, causes sudden death in cattle in Colombia, but it has not been established if it contains MFA. Currently the only alternatives for controlling the poisoning is the use of herbicides, manual removal of the plants, or the use of fences to prevent animals access. Research has demonstrated the possibility of using conditioned food aversion to avoid A. rigida ingestion. It has been demonstrated that goats greatly increased resistance to poisoning by ingestion of non-toxic amounts of A. septentrionalis or by transfaunation of rumen contents from resistant to susceptible goats. Bacteria that hydrolyze MFA were isolated from soil, from leaves of A. septentrionalis and Palicourea aeneofusca and from ruminal content of goats, suggesting that toxicity can be prevented by intra-ruminal inoculation of bacteria that hydrolyze MFA.
Amorimia spp.; acute heart failure; Mascagnia spp.; sodium monofluoroacetate; sudden death; toxic plants