[The course of early syphilis in morphine base-dependent rabbits]

Eleven rabbits made dependent on morphine base were observed which were infected with syphilis studying the clinical and serological course of the infection. The control group comprised five non-dependent rabbits infected with syphilis. After 30 days from the infection all animals were given procaine penicillin in daily doses of 75,000 mu/kg. The treatment was carried on for 20 days. In all animals the following serological tests: VDRL, IgG, FTA, TPHA, and TPI were done before the treatment and 1, 3, 6, and 12 months after it. Ulcerations at the site of injection of Nichols strain of spirochetae in all morphinedependent rabbits developed earlier (5-6 days after infection) than in controls (9-10 days), were much larger and persisted longer, while the antibody titres were lower, as a rule, in the morphine-dependent animals. The results presented justify the conclusion that the clinical and serological course of the early stages of syphilis is different in the morphine-dependent animals when compared with controls.