Spontaneous photosensitization by Heterophyllaea pustulata Hook. f. (Rubiaceae), in sheep from Northwestern Argentina.

Heterophyllaea pustulata Hook. f. (Rubiaceae) is a phototoxic plant. It grows in the Andean area of northwest of Argentina, and it causes significant economic losses in the livestock. This plant induces dermal lesions by photosensitization probably due to its content of photosensitizing anthraquinones. This paper describes an outbreak of poisoning in Corriedale sheepfold, which had an incidence of 49%. Ear skin biopsies and blood samples were collected of six affected animals. Liver enzymes remained within the reference limits. Histopathologically, a deep necrotizing dermatitis was identified in all samples. H. pustulata was identified in the areas of grazing. Anthraquinone concentration in leaves was 0.84% p/p, expressed as rubiadin. All findings allow us to conclude that the diagnosis is a primary photosensitization. Huge regional economic losses could be attributed to H. pustulata poisoning, although its toxicity has been little studied.

Gousiekte in African buffalo (Syncerus caffer).

Three African buffalo (Syncerus caffer) that died after capture and translocation from Mutirikwe Recreational Park in southern Zimbabwe showed macroscopic and microscopic lesions of cardiomyopathy compatible with a diagnosis of gousiekte. The buffalo had had access to Pavetta schumanniana, a plant that is known to cause gousiekte. Death was attributed to cardiac failure as a result of previous consumption of the plant, exacerbated by the stress of translocation.

Spontaneous poisoning by Palicourea marcgravii (Rubiaceae) in a sheep herd in southeastern Brazil.

Palicourea marcgravii (Rubiaceae) is considered the most important toxic plant affecting livestock farming in Brazil. This study describes an outbreak of spontaneous poisoning by P. marcgravii in sheep. Forty-nine sheep died while showing clinical signs of sudden death after having access to the plant. During the necropsy, P. marcgravii leaves were observed in the rumens of the animals. Histopathological analysis demonstrated hydropic degeneration of the kidneys. Monofluoracetate concentration obtained in Palicourea samples was 0.53% (5.3 µg/mg). These findings collectively indicate that the affected animals died from poisoning due to P. marcgravii.

Poisoning in goats by the monofluoracetate-containing plant Palicourea aeneofusca (Rubiaceae).

The epidemiological, clinical and pathological aspects of a spontaneous outbreak of Palicourea aeneofusca poisoning in goats are reported. The main clinical signs were motor incoordination, generalized muscle tremors, broad-based posture, tachypnea, tachycardia, vocalization and respiratory distress. Two goats died 5 and 20 min after the observation of the first clinical signs. Another that was found recumbent died 80 h later. One goat with mild clinical signs recovered. Congestion and hemorrhages were observed macroscopically and histologically in most organs. Pulmonary edema was also observed. The main microscopic findings consisted of cytoplasmic vacuolization and necrosis of the renal tubular epithelium. The average concentration of monofluoroacetate obtained in sixteen samples of P. aeneofusca was 0.29 ± 0.17%. It is concluded that P. aeneofusca is toxic to goats under natural conditions.

Earwax: A clue to discover fluoroacetate intoxication in cattle.

An innovative method was developed to detect fluoroacetate poisoning in cattle by headspace/gas chromatographic analysis of earwax samples of intoxicated cattle. Samples were collected from 2 groups of cattle subjected to induced fluoroacetate intoxication, each group receiving a different dose of acetamide (antidote). Monofluoroacetic acid was detected in samples of intoxicated cattle in concentrations inversely proportional to the dose of acetamide. Thus, earwax analysis represents a successful approach for detection and monitoring of fluoroacetate poisoning.