[The effect of trace elements on the infectious process in plague in an experiment]. / Vliianie mikroélementov na infektsionnyi protsess pri chume v éksperimente.

The influence of Mn, Fe, Co, Ni, Cu and Zn on experimental Yersinia pestis infection in three species of gerbils (Rhombomys opimus, Meriones meridianus, M. tamariscinus) under conditions, imitating natural biogeochemical anomalies, was studied. The addition of Co and Ni to the fodder given to the animals for the period of 2-4 weeks prior to infection aggravated the course of infection. In similar experiments Cu, Fe and Mn aggravated or, on the contrary, inhibited the development of infection, depending on the environmental conditions. The addition of Zn produced practically no effect on the course of the disease, but its use in combination with Cu, depending on the dose, inhibited or enhanced the action of this element. The addition of Cu, Fe and Mn to fodder made it possible to reproduce the effect of protection from plague, observed in nature in the presence of some biogeochemical anomalies. This result may serve as an argument in support of the concept stating that the chemical composition of the environment is a factor capable of regulating the infectious process in animals in nature.

[Lysogeny by phages specific to Yersinia pestis in bacteria of the microbiocenoses of wild plague-carrying rodents]. / Lizogeniia po fagam, spetsifichnym dlia Yersinia pestis, u bakterii mikrobiotsenozov dikikh gryzunov--nositelei chumy.

For the first time lysogenic bacteria of the genus Escherichia, spontaneously producing bacteriophages specific to the infective agent of plague, have been detected in the microbiocenoses of midday gerbils, plague carrier in the Volga-Urals natural focus. The morphological, cultural and biochemical properties of 22 lysogenic Escherichia strains isolated from wild rodents, as well as the spectra of the lytic activity of temperate bacteriophages produced by the above-mentioned microorganisms have been studied. Proceeding from the findings obtained in this research, all the strains have been divided into 3 lysotypes.

[Evaluation of the results of animal studies with a scheme of serologic reactions according to a table of standards]. / Otsenka dannykh issledovaniia zhivotnykh v sisteme serologicheskikh reaktsii po étalonnoi setke.

The authors suggest a method of processing of the data of examination of the animals in the system of serological reactions for the purpose of diagnosis of epizootic situations in the natural plague foci. Positive results are recorded in a table in the form of a grid whose cells correspond to all possible variants of the two reaction titres. The table is divided into 6 sections into which the results differing by the correlation and the absolute reaction titres (the standard grid) are placed. The frequency of reactions is determined by the grid sections in the regions in which the character of the epizootic development in nature was studied by bacteriological examination of the animals. The diagnostic scale is drawn by the results of such standard observations. The trial of the suggested method was carried out in the regions of plague epizootics among the Rhombomys optimus Licht. in the Lowland Kara-Kum; it was possible to differentiate the signs of epizootic situations there in greater detail than by the methods suggested earlier.