Outbreaks of dermatopathy caused by Tephrosia noctiflora intoxication in Brazilian cattle.

This study aims to update the knowledge concerning the intoxication by Tephrosia noctiflora in Brazilian cattle herds by reporting new cases of intoxication in lactating cows, their calves and bulls and highlight the epidemiology, clinical signs, pathogenesis, gross, and microscopic lesions. The morbidity and mortality of this intoxication in the farms studied was low. Gross lesions in all affected cattle consisted of dermatitis with hyperpigmentation, crusts, ulceration, erythema, and lichenification in the skin of limbs, ventral abdomen, perianal and perineal areas of lactating calves and adult cattle. Microscopically, the main lesion observed consisted of severe dermatitis with parakeratotic hyperkeratosis, papillated proliferation, and diffuse, accentuated lymphoplasmacytic inflammatory infiltrate in the epidermis and dermis. The presence of skin lesions mainly in the limbs and ventral abdomen of cattle implies the pathogenesis of intoxication is related to a primary contact dermatitis, and the occurrence of similar lesions on the skin of nursing calves reinforces this hypothesis. The putative toxins of T. noctiflora have been thought to be rotenoids. Additional work is needed to define better if these compounds are the main toxin responsible for the dermatopathy observed in these herds.

Dermatopathy caused by Tephrosia noctiflora intoxication in cattle.

An outbreak of a disease characterized by emaciation, dermatitis with erythema, alopecia, foul-smelling exudation, crusting, hyperpigmentation, lichenification, and edema of fore- and hindlimbs, chest and dewlap is described affecting cattle in the State of Alagoas, Northeastern Brazil. Microscopically, the main lesions were characterized by diffuse dermatitis with infiltration of lymphocytes, histiocytes, parakeratotic hyperkeratosis and acanthosis. The plant Tephrosia noctiflora, which exhibited signs of consumption, infested the grazing areas of cattle. To test its toxicity, T. noctiflora was harvested, dried in the shade, crushed and sourced at a concentration of 50% mixed with commercial food for three guinea pigs. The main clinical signs in guinea pigs included weight loss and multifocal, moderate to severe areas of alopecia, diffuse erythema of the skin, vaginal edema and hematuria. Microscopically, lymphocytic and histiocytic dermatitis, parakeratotic hyperkeratosis and acanthosis were noted in guinea pigs. This experiment confirms that T. noctiflora is the cause of outbreaks of dermatitis observed in cattle grazing in areas infested by this plant.