Pathogenicity of Spiroplasma sp. strain SMCA in Syrian hamsters: clinical, microbiological, and histological aspects

Abstract

The intracerebral inoculation of newborn Syrian hamsters with pure cultures of Spiroplasma sp. strain SMCA caused severe, prolonged disease involving the central nervous system, culminating in death. The disease was characterized by spasms, muscular tremors, disturbances in motor control, inability to feed, dramatic loss of weight, and runting. The effect was dose related, with the largest numbers of viable spiroplasmas producing the highest incidence of disease and death in the shortest period of time. Severe hemorrhaging developed throughout the brain, liver, and spleen, and spiroplasmas were readily recovered from these organs, indicating that the agent disseminated from the initial site of infection to distant host tissues. Newborn animals were susceptible, but adults were resistant; these findings are similar to those reported for newborn mice and rats. Unlike mice and rats, hamsters did not develop cataracts visible to the unaided eye. The histopathological features of eye disease in hamsters were different from those in rats and were characterized by microophthalmia (especially in runted hamsters) and abnormal proliferation, disorientation, and disorganization of corneal, lens, and retinal tissues. The significance of these findings is discussed.

Pathogenicity of Spiroplasma sp. strain SMCA in rabbits: clinical, microbiological, and histological aspects

“…Spiroplasma SMCA has been demonstrated to be pathogenic for chicken embryos, suckling mice, suckling rats, and suckling hamsters (2,5,6,10,11,13,14). The present data indicate that it is pathogenic for suckling rabbits also.…”

“…The special feature of the eye disease in rabbits is severe microophthalmia and severe cataract formation. Cataractous changes were also observed in mice and rats (2, 3), but not in hamsters (10).…”

“…As in the other animal species, the disease in rabbits is characterized by a general disease often ending with death and eye disease. Hamsters developed a severe disease characterized by spasms, muscular tremors, disturbances in motor control, lameness, dramatic weight loss, and runting (10). Infected rabbits, like mice and rats, did not show striking clinical features.…”

Spiroplasma eriocheiris Adhesin-Like Protein (ALP) Interacts with Epidermal Growth Factor (EGF) Domain Proteins to Facilitate Infection

“…Phylogenetic analysis of the 16S rDNA gene sequences of S. eriocheiris showed that this Spiroplasma strain had a close relationship with S. mirum (Wang et al, 2004a ). S. mirum isolated from the rabbit tick ( Haemaphysalis leporispalustris ) can infect vertebrates (Kirchhoff et al, 1981 ; Tully et al, 1982 ). It induced the presence of suckling mouse cataract agent (SMCA) (Zeigel and Clark, 1974 ).…”

A Proposed Life Cycle Model of Spiroplasma mirum Based on Scanning Electron Microscopical Observations of Growth in Liquid Culture

“…Spiroplasma mirum,originally isolated from a tick(Haemaphysalis leporispalustri) which parasitizes the cottontail rabbit, has been referred to as the "suckling mouse cataract agent (SMCA)" due to its association with the occurrence of cataracts in suckling mice following intracerebral inoculation (8). The pathogenicity of S. mirum has subsequently been confirmed for other animals including the rat (10), rabbit (11), and hamster (12).…”