Occurrence of histomoniasis (Enterohepatitis) in broiler breeder chickens by possible lateral transmission

Three, 30-week-old Hubbard broiler breeder chickens, died with clinical signs of inappetance, mild emaciation and bloody droppings, were necropsied. Their caeca were enlarged with firm thick walls and ulcerated mucosa covered with fibrino-necrotic exudates. No caecal worms were located but ascarid worms were present in the intestines. Hepatomegaly, with presence of greenish discolouration and numerous round to oval circumscribed cratered lesions, were noted. Microscopically, the livers revealed necrosis with extensive infiltration of lymphocytes, mononuclear cells, and scarce heterophils. Hepatocytes towards the periphery of the lesion contained punched out PAS positive ovoid bodies in the cytoplasm. The caeca showed hyperemia, ulcerations and infiltration of large number of heterophils, lymphocytes and macrophages often extending deep into the muscularis mucosae in which the ovoid bodies of 15–20 pm in diameter were admixed. Pooled fecal samples from the pens revealed the presence of Heterakis sp. and Ascarid ova. Earthworms and Heterakis sp. eggs could also be demonstrated in the litter. A diagnosis of histomoniasis was made.