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Concurrent infections with morphologically similar spirochaetal organisms may occur in the feet and colon of cattle in Japan.

ABSTRACT. A 37-day-old male Japanese black calf showing marked salivation and leucocytosis died and was examined the tissues histologically. Histological lesions were characterized by severe focal necrotic glossitis on the ventral side of the root of the tongue. Immunohistochemically, Fusobacterium necrophorum subsp. necrophorum antigen was detected in the necrotic tissues and its distribution corresponded to that of the gram-negative, nonsporeforming, long filamentous organisms. Ultrastructural similarities between the organism and F. necrophorum subsp. necrophorum, but not subsp. funduliforme were observed. These findings clearly demonstrated that the fatal necrotic glossitis was caused by F. necrophorum subsp. necrophorum. This is the first report of bovine fatal necrotizing glossitis with leucocytosis caused by F. necrophorum subsp. necrophorum infection, and this organism may be an important fatal pathogen in calves with glossal lesions. KEY WORDS: calf, fatal necrotizing glossitis, Fusobacterium necrophorum subsp. necrophorum.

ABSTRACT. A 21-month-old Thoroughbred colt showed continuous diarrhea and developmental retardation for 7 months, and was thereafter subjected to euthanasia for necropsy and laboratory examinations. At necropsy, the cecal and colonic mucosae were diffusely rough and hyperemic. Histopathologically, the mucosa and submucosa were edematous and were infiltrated by numerous lymphocytes and macrophages. Meanwhile, three morphological types of Brachyspira antigen-containing spirochetes were found to be numerous in the crypts and in the mucus layer over the epithelium in the cecal and colonic lesions. They were frequently observed in intercellular gaps and in the cytoplasm of degenerative epithelial cells, and in the lamina propria, particularly in cavities around blood vessels. These invasive intestinal spirochetes might be one of pathogens inducing colitis and diarrhea in horses. KEY WORDS: Brachyspira,equine, intestinal spirochete.J. Vet. Med. Sci. 64 (7): [633][634][635][636] 2002 The existence of equine intestinal spirochetes was reported in 1964 [1]. They were observed in Gram-stained smears of cecal contents from the majority of samples from 51 horses and ponies in Scotland, and were considered part of the normal intestinal flora. In 1985, two morphological types of spirochetes were found in the equine cecal contents, and this again suggested that such organisms were not pathogenic [2]. Perhaps because of these findings, equine intestinal spirochetes have received little attention. The prevalence and pathology of equine intestinal spirochetosis are not known, and associated enteritis and diarrhea have not been previously reported. This study describes the histopathological characteristics of a Thoroughbred colt with invasive intestinal spirochetes in Japan.On August 22, 2000, a 14-month-old Thoroughbred colt that had mild diarrhea (body weight 377 kg) was transferred to The Hidaka Yearling Training Farm of the Japan Racing Association (JRA) from a farm in Hokkaido. After moving onto the JRA farm, the colt was housed together with 76 other horses in a facility consisting of two stables and a large livery yard with soil. At that time, the colt took pleasure in his food and drank much water, approximately 100 to 150 liters a day. The referring veterinarian tried antiparasitic therapy with ivermectin and bithionol, anti-inflammatory therapy with flunixin meglumine and anti-hyperperistalsis treatment with hyoscine-N-butylbromide (Buscopan), but no change occurred. While being treated, fecal samples were collected for microbiological examination on September 13, but no enteropathogenic organisms, such as Salmonella, Clostridium or rotavirus were identified. The horse showed weight loss of 44 kg (body weight 333 kg) by October 10, but slowly grew to 424 kg at the necropsy. After a period of 7 months from the first diagnosis, the 21-monthold animal was subjected to euthanasia with anesthesia for necropsy and laboratory examinations on March 9, 2001. No clinical abnormality was found in any of the other horses.Several ...