Ocurrence of enzootic hematuria and epidermoid carcinoma of the upper digestive tract of cattle in Brazil

Abstract

Three bovine diseases, which occur in certain areas of Brazil, were studied: 1) a chronic intermittent hematuria, 2) a disease characterized mainly by snoring and difficulties in swallowing, and 3) a condition with regurgitation and chronic tympanism. In all three diseases there is progressive emaciation and the animals finally die. It is shown that the chronic intermittent hematuria is due to urinary bladder lesions. These were proliferations of capillaries, forming capillary and cavernous hemangiomas. In one case a nodule of epithelial hyperplasia was seen. The disease was diagnosed as bovine enzootic hematuria. The authors further showed that the symptoms of the second disease are due to epidermoid carcinomas of the pharynx, and that manifestations of the third condition are caused by epidermoid carcinomas of the oesophagus. In two animals, in addition to the bladder, pharyngeal and oesophageal lesions, an epidermoid carcinoma was observed in the rumen. All the carcinomas seen were of the keratinizing type. Coexisting lesions of the three diseases were found in the same animal. The authors think that the three conditions are different manifestations related to the same etiology. The most advanced lesion, which finally causes the appearance of symptoms, determines the disease the animal shows. The occurrence of bracken fern (Pteridium aquilinum (L.) Kuhn var. arachnoideum) is a common feature of the regions where the diseases are observed; on the other hand these diseases were only observed in cattle of these areas. Based on these findings and on data from the literature, the authors think that the occurrence of P. aquilinum plays an important role in the etiology not only of the bladder lesions, but also of the malignant growths observed in the upper digestive tract of cattle. Concerning the action of bracken fern the authors think that the younger the animals when they start to eat P. aquilinum, the less severe are the symptoms of acute poisoning. These animals, raised on bracken infested pastures, would not be affected later in their life any more by acute bracken poisoning, but they would he affected then by hematuria with neoplastic growth in the bladder and by carcinomas of the upper digestive tract. There seems to be an age linked incidence of the three diseases. Hematuria is observed first, in animals from two years of age onward. The symptoms caused by the pharyngeal carcinomas and specially the symptoms due to the oesophageal carcinomas were observed only in older animals from five years on. It is thought that the following factors may determine the appearance either of acute bracken poisoning or of neoplastic growth in the bladder and the upper digestive tract: 1) the age at which the animal starts eating P. aquilinum, 2) the amount consumed and the length of time the animal eats the plant.