An outbreak of poisoning by Kalanchoe blossfeldiana in cattle in northeastern Brazil.

In the world, Kalanchoe species are primarily ornamentals and houseplants, but some have escaped cultivation and can be found in the field. In Latin America, there are no reports of spontaneous poisoning by Kalanchoe species in animals. This study aimed to describe the epidemiological, clinical, and pathological aspects of an outbreak of poisoning by Kalanchoe blossfeldiana in cattle in the semiarid region of Pernambuco, Brazil. Epidemiological and clinical data were obtained from the owner and veterinarian during technical visits. Prunings of this plant were disposed of in a pasture with a shortness of forage. Seventeen cattle had clinical signs, and thirteen died 4-5 days after the first clinical signs were observed. Clinical signs and gross and histological lesions include gastrointestinal, cardiovascular, and neuromuscular disorders. Kalanchoe spp. contain cardiotoxic glycosides, and the clinical signs and lesions in cattle of this outbreak were consistent with poisoning by plants that contain these toxins.

Interacting impacts of invasive plants and invasive toads on native lizards.

The ecological impacts of an invasive species may be reduced by prior invasions if selective pressures imposed by earlier events preadapt the native biota to deal with the newer arrival. In northwestern Australia, invasion of the cane toad (Rhinella marina) kills many native predators if they ingest the highly toxic toads. Remarkably, the toads' defensive toxins (bufadienolides) are chemically similar to those of another invasive species: an ornamental plant from Madagascar, Bryophyllum spp. (Crassulaceae, mother-of-millions). Omnivorous lizards (bluetongue skinks, Tiliqua scincoides) are imperiled by the invasion of toads in northwestern Australia, but conspecifics from other areas of the continent (those where exotic plants were introduced and including areas where toads have yet to invade) are less affected because they exhibit higher physiological tolerance of toad toxins (and also of plant toxins). The willingness of captive bluetongues to consume both toads and these plants and the high correlation in the lizards' sensitivity to toad toxins versus plant toxins suggest that exotic plants may have imposed strong selection on the lizards' physiological tolerance of bufadienolides. As a result, populations of lizards from areas previously exposed to these alien plants may be preadapted to deal with the toxins of the more recent anuran invader.