[Yersinia pestis L-forms in rodents and ectoparasites]

Y. pestis L-forms and bacterial forms persist in the body of great gerbils for 40 days. L-forms are poorly phagocytized and can persist in phagocytes for a long time. In guinea pigs immunized with vaccine EV, Y. pestis antigen could be detected till day 160. An unstable L-form was isolated from Ornithodoros mites 3 years after their experimental infection with Y. pestis. Bacterial forms persist in mites for 1-3 years. For 5 years Y. pestis antigen is regularly detected in a high percentage of mites.