Intestinal spirochetosis in wild sika deer (Cervus nippon yesoensis) infected with Brachyspira species

Isolation of a Megatrypanum trypanosome from sika deer (Cervus nippon yesoensis) in Japan

A trypanosome was isolated from a sika deer (Cervus nippon yesoensis) in Hokkaido, Japan, during the primary culture of sika deer renal cells. This is the first report of isolation of a Megatrypanum trypanosome from Japanese Cervidae. The trypanosome, designated TSD1, was propagated and maintained in Eagle's modified essential medium containing 20% fetal bovine serum with sika deer renal cells as feeder. The TSD1 trypanosome was morphometrically similar to Trypanosoma cervi, which is commonly isolated from American and European deer. PCR analysis with primers for 18S ribosomal DNA and nucleotide sequencing showed that TSD1 is a member of genus Trypanosoma, subgenus Megatrypanum. Phylogenetically TSD1 is closely related to T. theileri, a common trypanosome of cattle, but is distinguishable from T. theileri by some morphometrical and biological features.

Immunohistochemical and ultrastructural detection of intestinal spirochetes in Thoroughbred horses

Studies of equine intestinal spirochetes have long focused on intestinal contents alone, but intestinal spirochetosis has been reported recently in a 21-month-old Thoroughbred colt in Japan. To define the clinical and pathological significances of intestinal spirochetosis in several horses, an epizootiologic survey with histologic, immunohistochemical, and ultrastructural methods was conducted for Brachyspira antigen-containing intestinal spirochetes in 12 diseased or injured Thoroughbred horses, aged from 35 days to 17 years. Brachyspira antigen-containing spirochetes were found in 7 of 12 horses (58.3%) and were more frequent in the cecum than in other parts of the bowel. It was not clear whether the infection was clinically related to diarrhea or dysentery, but histopathology revealed a close association between the bacterial infection and epithelial hyperplasia. Crypt epithelium consisted mainly of goblet cells and showed frequent mitosis throughout its length. Inflammatory cells and congestion were also present. There were numerous spirochetes in the crypts, and some invaded the cecal and colonic epithelia and underlying lamina propria. Ultrastructurally, the spirochetes were divided into 4 types. Three types were identified in degenerative epithelial cells or intracellularly. Brachyspira antigen-containing intestinal spirochetes invading the mucosa were capable of causing epithelial hyperplasia in the cecum and colon in the horses. The findings in this study will increase awareness of the importance of intestinal spirochetosis and may also be helpful for diagnosis and treatment of this condition.

Concurrent spirochaetal infections of the feet and colon of cattle in Japan

OBJECTIVE

To describe spirochaetal infections in the feet and colon of cattle affected with papillomatous digital dermatitis (PDD) and colitis respectively.

PROCEDURE

Eighty-two slaughtered animals were macroscopically examined for the presence of PDD. Tissues of two cattle affected with PDD were examined by histology, immunohistochemistry, electron microscopy and bacteriology for spirochaetal infection.

RESULTS

Two adult cattle (a 2-year-old beef bullock and 7-year-old Holstein dairy cow) were affected with PDD. Histologically, numerous argyrophilic and gram-negative filamentous or spiral spirochaetes were found deep in the PDD lesions. Epithelial and goblet cell hyperplasia and oedema of the lamina propria mucosa with macrophage and lymphocyte infiltration were observed in the caecum and colon in the cattle. Numerous spirochaetes were present in the crypts and some had invaded epithelial and goblet cells, and caused their degeneration. Immunohistochemically the organisms stained positively with polyclonal antisera against Treponema pallidum and Brachyspira (Serpulina) hyodysenteriae. Ultrastructurally, the intestinal spirochaetes were similar to the spirochaetes in PDD. They were 6 to 14 pm long, 0.2 to 0.3 pm wide and had 4 to 6 coils and 9 axial filaments per cell. Campylobacter species were isolated from the PDD and intestinal lesions, but spirochaetes were not.

CONCLUSION

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

Intestinal spirochetosis in a 21-month-old thoroughbred colt

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.