[Leptospira infection under the natural conditions of the environs of Saint Petersburg]. / Leptospiroznaia infektsiia v prirodnykh usloviiakh okrestnostei Sankt-Peterburga.

The existence of valent natural foci of leptospirosis, stable and polyhostal, under the conditions of urban agglomerations has been established. In an intensively urbanized landscape, the foci of mixed (natural and anthropic) type can be found. Depending on the character of microlandscape in a given zone, the main hosts of leptospires are different species of small mammals in whose populations, as a rule, the circulation of at least three Leptospira species is observed. Introduction of the 'carriership index' will help determine the role of different species of small mammals as the potential source of leptospires in the foci, as well as the proportion of different circulating Leptospira species and their zonal distribution.

[Characteristics of the interaction of Leptospira with the host organism in the infectious process in golden hamsters]. / Osobennosti vzaimodeistviia leptospir s organizmom khoziaina pri infektsionnom protsesse u zolotistykh khomiakov.

The comparative evaluation of the interaction of L. icterohaemorrhagiae strain P, L. canicola strain CL and L. hebdomadis strain 650 with golden hamster liver and kidney cells is presented. Three variants of the course of Leptospira infection have been distinguished: (1) the hepato-renal (icteric) variant, caused by the adhesion of leptospires to liver cells with the colonization of their surface and the disaggregation of liver-cell complexes and by the accumulation of leptospires in the kidney interstice; as a consequence, parenchymatous hepatitis and nephroso-nephritis develop, which lead to the death of animals; (2) the renal (anicteric) variant, characterized by the absence of the infective agent and lesions in the liver, by adhesion of leptospires to and their colonization of the nephrothelium of the proximal convoluted tubules of the kidneys; in this case some of the animals die because of renal insufficiency and shock, while in the surviving animals prolonged carrier state develops; (3) the intermediate variant, characterized by the initial process of leptospiral adhesion and colonization in the liver and its subsequent progress in the kidneys.

[Interaction of Leptospira with the host's body in the infectious process in guinea pigs]. / Vzaimodeistvie leptospir s organizmom khoziaina pri infektsionnom protsesse u morskikh svinok.

In experiments on guinea pigs the pathogenicity of leptospires is manifested by their adhesion to liver cells, colonization of the surface of these cells, accumulation of leptospires in the renal interstice and their colonization of the nephrothelial surface of proximal convoluted tubules in the kidneys, by toxic microcirculatory disturbances, dystrophy and necrosis of nephrothelial cells. Then the primary toxic action of circulating leptospires, microcirculatory disturbances and hemorrhagic syndrome augment during the colonization of the surface of liver cells, accompanied by their dystrophy and dissociation, as well as by jaundice. The accumulation of leptospires in the renal interstice and their subsequent multiplication on the nephrothelium of the proximal convoluted tubules are responsible for the development of interstitial nephritis and necrotic nephrosis. The persistence of lesions in the liver and kidneys, occurring in some cases in spite of elimination of the infective agent from these organs due to increasing antibody production suggests the toxic action of immune complexes.

[Antigenic structure of leptospires of the Canicola serogroup isolated in the north-western regions of the RSFSR]. / Kharakteristika antigennoi struktury leptospir serogruppy Canicola, vydelennykh na severo-zapade RSFSR.

The comparative study of 16 Leptospira cultures, serogroup Canicola, isolated from humans and animals in different years in the North-West of the RSFSR and 2 reference strains of the Canicola serovar, Hond Utrecht IV and Kashirsky, was carried out in the agglutinin cross-adsorption tests. The absence of the antigenic homogeneity of the cultures under test was established: 9 of them proved to be identical to strain Kashirsky and 7, to strain Hond Utrecht IV.

[Clinico-morphological characteristics of leptospirosis]. / Kliniko-morfologicheskaia kharakteristika leptospiroza.

Observations in 5 patients dying with leptospirosis (at 6-30 days after the onset) caused by leptospira of the Hebdomadis serogroup are described. Bright jaundice developed due to severe serous liver centrilobular edema with pronounced dissociation of the liver cell bands, cholestasis, and cloudy swelling of hepatocytes. Albuminuria, oliguria, and uraemia were caused by acute tubular and interstitial nephritis. Hemorrhagic diathesis with small bleedings in the skin, mucous and serous membranes was associated with the impairment of permeability of microcirculatory vessels. Focal necroses of skeletal muscles, myocardiodystrophy, and focal myocarditis, serous leptomeningitis were also seen. Few leptospirae could be detected extracellularly (often attached to the outer host cell membranes) by Warthin-Starry's method of silver impregnation of paraffin sections and by indirect immunofluorescence, much more rarely could they be demonstrated by Levaditi's method of silver impregnation of pieces of the viscera. Most leptospirae were present in the liver in the case of death on the 6th day when no antibodies were yet present in the blood. Since the 9th day when the antibodies did appear, leptospirae gradually disappeared from the liver and were found in the kidneys. It is suggested that some leptospiral cytotoxic products play a role in the pathogenesis of leptospirosis.