RESUMO
Atypical interstitial pneumonia in cattle associated with the ingestion of damaged sweet potatoes is reported in the State of Paraíba, Northeastern Brazil. The sweet potatoes were severely damaged by Myzus tersicae, and had an obvious fungal infection. Eighteen milking cows, 1 bull and 1 steer were fed approximately 400 kg of the sweet potatoes. Six days after consumption 13 cows were affected with labored abdominal breathing, extended and lowered head, coughing, expiratory grunt, salivation and protruded tongue. Six animals died and the others recovered in 4-7 d. At necropsy lungs were distended and did not collapse when the thorax was opened. Bullous emphysema and gelatinous exudates were observed in the interlobular, peribronchial and subpleural tissues. Microscopically, the lungs had severe edema and emphysema, congestion, and alveolar epithelial cell hyperplasia. The sweet potatoes were cultured but Fusarium spp was not isolated, probably because a zigomycete fungus covered the plates in 48 h of incubation.