Cecal rupture by Anoplocephala perfoliata infection in a thoroughbred horse in Seoul Race Park, South Korea.

A 7-year-old Thoroughbred horse was admitted to the Equine Hospital, Korea Racing Association with signs of colic. Based on the size of impactions, the clinical signs, the results of abdominal paracentesis and medical treatment, the prognosis was poor. The horse died 3 hours later following hopeless discharge. At necropsy, the caecum and large colon were fully filled with fecal contents and there was a rupture (10 cm in dia) in the latero- ventral caecum. The mucosa of the ileo-caecal and caeco- colic valves appeared to the hyperemic, edematous and ulcerous. There were many tapeworms in the affected mucosa. Histopathologically, lesions included hyperaemia, a deep necrotic inflammatory lesion and ulcers in the mucosa and submucosa of ileo-caecal and caeco-colic valves. One hundred thirty four faecal samples were obtained from 16 stables and submitted to parasitic examination. A total of 4 genera of eggs were recovered: Stongylus spp (82.1%), Anoplocephala perfoliata (10.5%), Bovicola equi (0.7%) and Parascaris equorum (1.5%). The major findings in this study are the presence of A perfoliata and its suspected association with the colic which led into an eventual caecal rupture. This study indicates the needs for an epidemiological survey of colic that is associated with Anoplocephala.

Promoting role of Clonorchis sinensis infection on induction of cholangiocarcinoma during two-step carcinogenesis.

Chronic Clonorchis sinensis (CS) infection is etiologically related to cholangiocarcinoma (CHCA) in human and animals. This study was carried out to clarify the role of CS infection on dimethylnitrosamine (DMN)-induced cholangiocarcinogenesis. Fifteen hamsters were administered with 15 ppm DMN for 4 weeks and one week later, the hamsters were infected with 15 metacercariae of CS (DMN-->CS group). The other 15 hamsters were infected with CS and after 5 weeks they were treated with the drug, praziquantel. Again one week later, the hamsters were administered with DMN (CS-->DMN group). The other 15 hamsters were administered with DMN and CS simultaneously (CS+DMN group). Histopathological examination of the livers showed CHCA with papillary or adenomatous hyperplasia of bile ductules in 3 of 15 hamsters of DMN-->CS group and in 11 of 15 hamsters of DMN+CS group. These results suggest that CS infection to hamsters may have a promoting effect on the development of CHCA.

Effect of Clonorchis sinensis infection and dimethylnitrosamine administration on the induction of cholangiocarcinoma in Syrian golden hamsters.

The study was carried out to observe the effects of Clonorchis sinensis infection on induction of cholangiocarcinoma in Syrian golden hamsters to which 15 ppm dimethylnitrosamine (DMN) solution was administered for 8 weeks. The histopathological changes of the bile duct and liver cells were observed at the 11th week. In six of 8 hamsters (75%) which were treated with DMN and then infected with C. sinensis, the livers developed cholangiocarcinoma at 10 weeks after the infestation of C. sinensis. The features of cholangiocarcinoma lesions were adenomatous or papillary hyperplasia of the bile duct epithelia showing distinct anaplastic changes with mucinous cell metaplasia and necrotic area. In the hamsters which received either DMN or C. sinensis alone, the livers showed only hyperplastic changes of the bile duct epithelial cells. It was suggested that C. sinensis infection and DMN administration could be a synergism on the development of cholangiocarcinoma in Syrian golden hamsters.

Pathology of infection caused by Dermatophilus-like organisms in porcine tonsils.

The authors investigated the occurrence of Dermatophilus-like organisms in sulphur granules of porcine tonsils. Light and electron microscopic studies, together with histochemical examination, were carried out to elucidate the mode of growth of the organism in the tonsils, the interaction between the organisms and host cells, and the nature of the radiating clubs around the organisms. Sulphur granules were found in about 15 and 70 per cent of market pigs and breeding pigs, respectively. Of the pigs having tonsillar granules, Dermatophilus-like organisms were observed in about 70 per cent of market pigs, and in nearly all breeding pigs. The organisms invaded tonsillar crypts to produce lesions resembling actinomycotic abscesses up to 5 mm in diameter. Dermatophilus-like organisms were demonstrated in various morphological forms ranging from filamentous to tuber-shaped or coccoid bodies. In the lesion, the bacterial cells adjacent to the host cell reaction showed distinct degenerative changes forming thick amorphous masses on the surface of the bacterial cells. The amorphous masses seemed to be derived from the bacterial cells but showed histochemical components different from those of the bacterial cells. These masses had numerous protrusions forming clubs. Phagocytic neutrophils close to the amorphous masses were presumed to play a role in deposition of the club material. Macrophages also appeared to participate in the inflammation leading to a granulomatous lesion. These findings suggested that the clubs might be formed by an interaction between the organisms and host cell reaction.