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Biomedical subjects

N G Olsuf'ev

Publications and source records attributed to N G Olsuf'ev.

At least 19 recordsLinked to original sources
PubMed1989

[Various mechanisms of formation of chronic tularemia in highly-sensitive animal species (Microtus rossiae-meridionalis)].

Experiments on voles belonging to the tularemia-sensitive species Microtus rossiae-Meridionalis, infected with Francisella tularensis highly virulent strain 503, have been carried out with the aim of studying the pathogenesis of chronic tularemia. The experiments have been made with the use of live and killed microbial cells. The significance of the multiple oral administration of killed bacteria to voles for the development of the atypical form of infection has been shown. The possibility of the early (on day 2) formation of antibodies in the blood of some of the animals has been established. Repeated feeding has been found to lead to almost 100% seroconversion in the animals. This fact can be attributed to the rapid spread of the antigen (1-5 hours) in the organs of individual animals. Besides, the causative agent is present in large amounts in lymphoid formations of the intestinal tract and in the lumen of the intestine, which creates conditions for the early contact of the massive dose of the antigen with immunocompetent cells and for the rapid development of systemic and local immune response. Morphological study indicates the presence of the rapid (24 hours) proliferative reaction of the cells making up the lymphoid apparatus of the intestine, their plasmocytic and macrophagal transformation. Thus, after the infection of voles with a mixture of live and killed bacteria the development of the early phases of the infectious process occurs simultaneously with the systemic and local transformation of the macroorganism, which contributes to the benevolent course of the infectious process in some of the animals.

Animals↗
PubMed1987

[Possible atypical course of tularemia (persistence) in the common vole Microtus arvalis Pall].

The possibility of the atypical course of tularemia with the prolonged persistence of Francisella tularensis in common voles (M. arvalis), the twin species of East European voles (M. rossiaemeridionalis), was studied. Experiments were made on 33 animals grown in the laboratory. F. tularensis strain 165 was used. The animals were infected by feeding them according to the previously developed scheme. 7 out of 33 voles showed the atypical course of tularemia: in 3 voles the disease took a prolonged course with bacteriuria and death on days 25-34; 3 other voles with bacteriuria registered before days 33, 66 and 172 (the term of observation) survived. The surviving animals were killed on day 183, and the presence of bacteria in their organs and seroconversion were established. One vole excreted no bacteria with urine and had no bacteria in its organs (the animal was examined on day 156), but in its blood specific antibodies were detected. To determine bacteriuria, the immunofluorescence test was used together with biological assays. Thus, M. arvalis, like M. rossiaemeridionalis studied earlier, can harbor F. tularensis at the period between epizootics. When voles of the former species penetrate stacks of straw and hayricks, conditions appear for the transfer of the infection to the latter species, M. rossiaemeridionalis. Therefore, in the foci of the meadow-field type each of these two species of voles may be not only of epizootic, but also of epidemic importance.

Animals↗
PubMed1983

[Higher fatty acid composition of the intraspecific taxa of Francisella tularensis].

The higher fatty acid composition of 27 F. tularensis strains differing in their biological properties and belonging to different intraspecific taxons has been determined with the use of gas and liquid chromatography. All the strains under study have been found to possess similar fatty acid spectra, characterized by the presence of long straight-chain fatty acids (saturated and unsaturated) with the number of carbon atoms varying from 10 to 26. Quantitative differences content of individual fatty acids (C10:0, C14:0, C24:0) have been revealed in various F. tularensis subspecies, which can serve as an additional criterion for their differentiation. The peculiar features of the higher acid composition of F. Tularensis give grounds for considering this species to be taxonomically independent and characterize its intraspecific taxons by the quantitative content of individual fatty acids.

Chromatography, Gas↗
PubMed1982

[Experimental latent tularemia in common voles].

Common voles (Microtus subarvalis) were infected with tularemia by feeding them with the corpses of the animals which had been infected with Francisella tularensis strain having somewhat decreased virulence. This resulted in nonlethal infection in 14 out of 433 voles used in the experiment. A considerable part of the animals having had the infection developed bacterial carriership (11 out of 13 animals) with bacteriuria (8 out of 11 animals) lasting up to 2 months. The persistence of Francisella tularensis in the body of the animals having had the infection could last as long as 6-11 months. The possible epizootological importance of the latent course of tularemia infection in common voles is discussed.

Animals↗
PubMed1980

[Concerning the term "zoonosis"].

The term "zoonosis", for a long time widely used in medicine, but not in veterinary, is considered in a historical aspect. In accordance with the decision of WHO/FAO Joint Expert Committee on Zoonosis, this term denotes diseases and infections which are naturally spread due to contacts between vertebrate animals and man. The terms "anthropozoonosis" and "zooanthroposis", as well as their variants, proposed by some authors should be discarded.

Animals↗
PubMed1976

[Half a century since the discovery of tularemia in the USSR].

The all-round and detailed study of tularemia carried out in the USSR for 50 years (1926-1976) offered a possibility to lay scientific foundation and to carry out an effective control of this infection in the whole country, providing a sharp and stable reduction of the incidence of this infection in man. By a number of sections and by practical results tularemia investigations in the USSR excelled foreign data.

History of Medicine↗
PubMed1975

[Detection of the causative agent of tularemia in the organs of animals in the early stages of development of the infection].

A study was made of a possibility of detection of the causative agent of tularemia in the organism of albino mice at early stages of development of the infection after subcutaneous infection with 1, 10 and 100 microbial cells of strains No. 503/834 (Holarctic race) and Schu (nearctic race). The following examinations were made: cultivation on nutrient media, immunofluorescent study, the antibody neutralization test and the passive hemagglutination test with erythrocytic diagnostic agents. The microbe could be regularly revealed three days after the infection. Detection of the causative agent was possible in individual cases at the earlier dates by seeding and by the fluorescent antibody method. Although by cultivation it is possible to reveal individual microbes, but the growth appears on the 3rd--5th day and later. The most rapid response (1.5--2 hours) results (on the presence of the microbe) can be obtained with the aid of the fluorescent antibody method. Application of the mentioned tests with the erythrocytic diagnostic agents permits to obtain data not only on the presence of the causative agent, but also on its quantity of the causative agent in the organism of the infected animal. The mentioned methods provide the most complete characteristics of the dynamics of the accumulation of the microbe in the animal organism.

Animals↗
PubMed1975

[Erysipeloid on the islands of the Sea of Okhotsk. I. The sources and vectors of the causative agent of erysipeloid].

The foci of the causative agent of erysipeloid at the islands of the Okhotsk sea were of the polyvector and polyhostal character. There were recorded 92 species of the naturally infected by the erysipeloid causative agent invertebrate inhabitants of the sea, fish, amphibia, reptilia, birds, mammals and ectoparasites of the warm-blooded animals. Gamazoid and ixodes ticks, mosquitoes, horse-flies and flees were found to be naturally infected with erysipelotrix. Ixodes persulcatus were found to be capable of infecting albino mice during blood sucking.

Animals↗