Spiral-shaped organisms on the surface colonic epithelium of the monkey and man

Abstract

Intestinal spirochetosis is the infestation of the gut mucosa by spiral-shaped organisms. Intestinal spirochetosis was studied in healthy rhesus monkeys (Macaca mulatta) and human subjects by histology, histochemistry, transmission and scanning electron microscopy. The incidence of intestinal spirochetosis is 28% in monkeys and 2% in human subjects. Intestinal spirochetosis is not associated with any gastrointestinal symptoms. In both primates, the morphologic characteristics and the relationship to the host are indistinguishable. Spiral organisms stained with H & E appear as broad basophilic haze on the colonic surface and are strongly positive by Warthin-Starry (silver) stain. Spiral-shaped organisms include two structurally different organisms, spirochetes and flagellated microbes. They intimately populate the brush border region of the surface of the colonic epithelium. They are absent in the crypt and in the small intestine. Infestation by spirochetes produces no alterations of cytocomponents of the underlying host structures. Under as yet undetermined conditions, spirochetes are capable of penetrating beyond the brush border region into the epithelial cytoplasm and also into the lamina propria. Although this occurrence is very rare, it is possible for mucosal penetration, when it occurs in large numbers to cause structural alteration and clinical symptoms in hosts.