Uveitis in rabbits with pleural effusion disease. Clinical and histopathological observations

Pleural effusion disease (PED) is a generalized infection of laboratory rabbits caused by a virus-like agent. The disease was first described in the late sixties as a mortality problem among rabbits used for the propagation of Nichols' pathogenic Treponema pallidum in Scandinavian laboratories using the T. pallidum immobilization (TPI) test for the serological diagnosis of syphilis. The iridocyclitis, described as a manifestation of PED, has been studied in detail in rabbits experimentally infected with the PED agent. All rabbits surviving the acute phase of infection developed a non-pyogenic, non-granulomatous anterior uveitis during the "viraemic" stage of infection. The ocular signs of disease culminated between days 3 and 6 and disappeared within 2 to 3 weeks. No recurrence of uveitis was observed during a 6-months observation period, nor by subsequent subcutaneous re-inoculation of the PED agent. Histologically, the uveal reaction was mild and regressed almost completely within 4 weeks. Discrete choroidal inflammatory foci occurred in some of the re-inoculated rabbits, but without changes in the anterior eye segment. The uveitis of pleural effusion disease in rabbits seems to be caused directly by the virus-like agent. It might possibly serve as a simple and reproducible model in further uveitis research.