Influence of Radioactive Contamination of the Sr-90 Terrestrial Ecosystems on the Enzymatic Activity of the Soil

One of the most promising methods of soil diagnostics is the determination of the parameters of enzymatic activity. Changes in urease, invertase, dehydrogenase and catalase activity of soil subjected to radioactive contamination with radionuclide Sr-90 have been studied. When the specific activity of Sr-90 in the soil varies in the range from the control value to more than 1.5 kBq / kg, the stability of invertase, urease and dehydrogenase is established. At the same time, the catalase activity of the soil is a sensitive indicator to radioactive contamination, which is described by a reliable model with a threshold value, after which the oppression of the indicator is observed

INFECTION OF LABOUR MIGRANTS FROM CENTRAL ASIA AND RESIDENTS OF ST. PETERSBURG AND THEIR SUSCEPTIBILITY TO VARIOUS INFECTIOUS DISEASES

Wide migration processes typical for megacities, including St. Petersburg, require a comprehensive study of the infection among migrants arriving on a work visa. Biological material for research was taken from 370 migrants who arrived in St. Petersburg on a work visa. The control group is represented by 320 adults of St. Petersburg. The methodology of the study of the biological material depended on the type of pathogen and included classical and modern methods of research. All obtained data are processed using adequate methods of mathematical statistics. C. diphtheriae strains in migrant workers were isolated 80 times more often than in permanent residents of St. Petersburg. In St. Petersburg gravis biovar occurs in 25% of cases, in the visiting contingent — in 83% of cases, which is an unfavorable prognostic sign. In migrants 17% of C. diphtheriae strains have a “silent” gene (tox+), which, under known conditions, can resume toxin production. The local people are protected from diphtheria by 95%, and labor migrant is only 66%. 17% of migrant workers with C. diphtheriae strains have a low level of protection against diphtheria, which poses a threat to them and those in contact with them. Infection with brucellosis pathogens of labor migrants from Uzbekistan is 9 times higher than the local population, persons from Tajikistan — 60 times higher. The infection rate of migrant workers from Uzbekistan and Tajikistan C. burnetii is 25 times higher than that of the local population. The chronic course of these infections complicates diagnosis and reduces the quality of life. According to the results of the screening test, S. Typhi bacterium carrier is distributed 7 times more in migrant workers from Uzbekistan and 2 times more in persons from Tajikistan than among the local population of St. Petersburg. The seroprevalence of toxic H. pylori in migrant workers is 84%, which is much higher than that of permanent residents of St. Petersburg (57%). The causes of this phenomenon have not been studied and require further study. Labor migrants from Central Asia have a low level of population immunity to parvovirus infection: 37% of seropositive persons from Uzbekistan and 62% from Tajikistan compared with 78% of the local population. This may contribute to the spread of parvovirus infection involving infection of seronegative residents of St. Petersburg risk groups, including blood donors, pregnant women, persons with immunodeficiencies, hematologic and oncologic patients. The results obtained ascertain the tense epidemiological situation among labour migrants in St. Petersburg for a number of infections. Reliable information will help to organize the correct further study of the problem and conduct appropriate measures to preserve the health of the local population and the visiting contingent