Direct isolation in cell-free medium of a spiroplasma fromHaemaphysalis leporispalustris (Acari: Ixodidae) in Maryland

Rabbit lens cell cultures in the characterization of Spiroplasma mirum pathogenicity

Spiroplasma mirum grew to high titres, 10(8) colour-changing units per ml of supernatant medium, and produced cytopathology which consisted of vacuolization, granulation and polynucleation . S. mirum did not grow in cell culture medium (Dulbecco's MEM+10% foetal bovine serum), thereby indicating the need for cultured cells or a cell culture product. Growth was also obtained from cell-free supernatants from AG-4676 cultures. S. mirum propagated in AG-4676 produced cataracts and death in suckling Wistar rats.

Localization and persistence of spiroplasmas in an experimental brain infection in suckling rats

The GT-48 strain of Spiroplasma mirum was employed in an experimental brain infection in 1-day old suckling rats in order to define the localization and persistence of organisms in brain and spleen and to evaluate the responses of three distinct genetic lines of rats. Rat pups inoculated intracerebrally with 30-300 organisms exhibited peak infections at 15-20 days post-inoculation, while challenge levels of 3-30 organisms showed some persistent infections for as long as 60 days. The responses of three genetic lines of rats to the experimental spiroplasma infection did not differ significantly over a 60-day follow-up period. The acute-phase infection in suckling rats showed a rapidly developing and widespread dissemination of organisms to all major areas of the brain.

Helical mycoplasmas (spiroplasmas) from Ixodes ticks

A new spiroplasma isolated from Ixodes pacificus collected in Oregon was serologically and morphologically distinct from known spiroplasmas. The new spiroplasma could also be isolated in tick cell cultures. Discovery of a new fastidious mycoplasma in ticks offers opportunities to explore the possible role of these agents in human and animal diseases.