[Effect of the prolonged contact of a flea population with plague bacteria on the infective activity of vetors]. / Vliianie dlitel'nogo kontakta populiatsii blokh s bakteriiami chumy na zarazhaiushchuiu aktivnost' perenoschikov

Results of the experimental infection of fleas (X. cheopis) with the plague agent after their long (2.5 years, 19 generations) feeding on infected white mice showed no difference in the infection activity of these insects as compared to control ones. The authors question the hypothesis according to which a low frequency of protein-formation in some species of fleas is due to their long contact with the plague agent in the historical past.