[Experimental latent typhus].

Asymptomatic typhus infection was regularly modelled in guinea pigs with increased resistance to Rickettsia prowazeki; this infection was characterized by the presence of immunological shifts in the blood and immunity to reinfection, persistenc of rickettsia in the organs of animals in the absence of pyretic reaction and periorchites. Modelling in guinea pigs of asymptomatic infection is also possible against the background of passive immunity created by specific immune serum obtained during convalescence. Investigations demonstrated that rickettsiocidal activity (in experiments on chick embryos) and antiinfectious activity (in experiments on guinea pigs) of the sera was caused by 7S-antibodies.