Naturally occurring Centratherum punctatum Cass. (Asteraceae) poisoning in sheep in northeastern Brazil

Centratherum punctatum Cass. (Asteraceae) is a widely distributed plant in northeastern Brazil and has been associated with natural poisoning in cattle and goats, as well as experimental intoxication in sheep. However, naturally occurring poisoning in sheep has not previously been documented. This study describes the epidemiological, clinical, pathological, and histopathological findings of two outbreaks of C. punctatum poisoning in sheep from the semiarid region of Paraíba State, northeastern Brazil. In Outbreak 1, 20 sheep grazing in a forage cactus (Opuntia spp.) field heavily invaded by C. punctatum developed soft feces, diarrhea, dehydration, and rapid loss of body condition. All animals recovered spontaneously after access to the plant was prevented, while forage cactus consumption continued. In Outbreak 2, four sheep received freshly harvested forage predominantly composed of C. punctatum. The adult ewe and ram developed only soft to pasty feces and recovered within five days after plant withdrawal, whereas two lambs developed severe gastrointestinal disease and died. Fecal egg counts were low, hematological findings were unremarkable, and hepatic and renal biochemical parameters evaluated in Outbreak 2 remained within their respective reference intervals. Necropsy of the lambs revealed lesions predominantly affecting the gastrointestinal tract, including ruminal reddening, ruminal tympany and dry, compacted gastrointestinal contents in one lamb, and abundant fluid gastrointestinal contents in the other, abomasal edema with multifocal superficial erosions, and intestinal hyperemia. Histologically, the forestomachs showed epithelial degeneration, cytoplasmic vacuolation, multifocal erosions, adherent necrotic cellular debris, mild mixed inflammation, and vascular congestion. The abomasum showed multifocal superficial erosions, while the small intestine exhibited moderate diffuse lymphoplasmacytic enteritis without identifiable parasitic structures. The convergence of epidemiological, clinical, laboratory, and pathological findings, together with recovery after plant withdrawal, supports C. punctatum as the cause of disease. This study provides the first detailed characterization of naturally occurring C. punctatum poisoning in sheep.