Studies on schistosomiasis. 6. A field outbreak of bilharzia in cattle.

VAN WYK, J . A., BARTSCH, R. C., VAN RENSBURG, L. J ., J:IEIT~~NN, L. P. & GOOSEN, P. J., 1974. Studies on schistosomiasis. 6. A field outbreak of bilharzia m cattle. Onderstepoort J. vet. Res., 41(2) 39-50 (1974) . . . . . An outbreak of bilharzia (Schistosoma mattheet) mfestat10n mvolvmg about 100 oxen on the farm Otthilie near Tolwe in northern Transvaal is described. Infestation of the cattle appears to have occurred per os from a single drinking trough. . . . The cattle showed clinical signs and pathological lesions of both the remfestat10n and the acute syndromes. The worm burdens were the highest recorded hitherto in naturally infested cattle. Severe macroscopic clay pipe stem periportal fibrosis, granulomata of the ureters and severe grey pigmentation of the lungs, are described for the first time in l}atural!Y in~ested cattle. ~~ere was mo~e marked liver pigmentation than had been encountered prevJOus_ly m this host. A s~nkmg feature m every case was conspicuous congestion and enlargement of the ileo-cecal valve, which was dark red in colour. . Treatment of affected animals with injectable trichlorphon controlled the outbreak Without causing mass embolism and liver infarcts. At least 11 treatments at a dosage level of 10-12 mg/kg per treatment at 3-5 day intervals are necessary. Faecal examinations for eggs or miracidia cannot be used to assess the worm burde_n or the clinical state of the animal. Moreover, it is suggested that this disease may be _confus~d With other conditions and this probably accounts for the rarity of reports of outbreaks m rummants.