Biomedical subjects
Publications and source records attributed to T V Doskina.
The article is dedicated to present-day problems of sanitary-virologic monitoring of water with different degree of pollution. The authors assess some indirect indicators of viral contamination of water and present perfected methods of water monitoring such as PCR, OT-PCR, and OT-PCR integrated with tissue culture for detecting viral RNA and DNA.
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Bound chlorine in doses 0.8-1.2 mg/l does not inactivate viruses in water. Chlorine can be active against hepatitis A viruses in concentration not less than 4.2 mg/l with the virion content in water 10(5)/ml and at least 20 min exposure.
On the territory of town Perm there are some factors of hygienic, climatic and technical nature which yearly influence microbial pollution of drinking water and seasonal incidence of intestinal infections of obscure etiology. It was shown in several years investigations.
It has been found out that a coli-phage is a more reliable indirect indicator of viral pollution of drinking water that the existing indirect bacterial indicators. Coli-phages concentration in drinking water on the level of single PFU/1 is evidence of disturbances in the barrier function of water-treatment facilities with respect to viral microflora and of the possible epidemic danger of water with respect to viral infection. The absence of coli-phages in I 1 of water sample should be considered the standard level of coli-phages of drinking water.
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The authors made an experimental study of the efficiency of water purification procedures based on the combined use of active chlorine and coagulants and hygienically evaluated the procedures. The study included the evaluation of water disinfection with various coagulants and active chlorine; the investigation of the processes of production of deleterious organic chlorine compounds; the assessment of the quality of water after its treatment. The coagulants representing aluminum polyoxychloride: RAX-10 (AQUA-AURATE 10) and RAX-18 (AQUA-AURATE 18), and aluminum sulfate, technically pure grade were tested. The treatment of river water with the coagulants RAX-10 and RAX-18, followed by precipitation, filtration, and chlorination under laboratory conditions, was shown to result in water disinfection to the levels complying with the requirements described in SanPiN 2.1.4.1074-01. RAX-18 showed the best disinfecting activity against total and heat-tolerant coliform bacteria, but also to the highly chlorine-resistant microrganisms--the spores of sulfite-reducing Clostridia, phages, and viruses. Since the coagulants have an increased sorptive capacity relative to humus and other organic substances, substitution of primary chlorination for coagulant treatment may induce a reduction in the risk of formation of oncogenically and mutagenically hazardous chlorinated hydrocarbons.
Quantitative relationships were studied between the indicators (common coliform bacteria (CCP), glucose-positive bacteria (GPB), thermoduric bacteria (TDB), coliform bacteria, enterococci, clostridia, coliphages) and the opportunistic (Pseudomonas aeruginosa, Proteus, Klebsiella) and pathogenetic (Salmonella and intestinal viruses) microorganisms at the stages of effluent purification and decontamination, in processes of self-purification in the water reservoirs and of water preparation at water-supplying stations, as well as in the association with the incidence of acute intestinal infections of bacterial and viral genesis in different climatic zones of the country. Salmonella and the opportunistic bacteria of the Enterobacteriaceae family and Pseudomonas aeruginosa were found to be highly resistant to detoxifying agents and environmental factors, adaptable, able to reproduce in pure water, to long survive in underground waters, and to accumulate when water is desalinated at the erections. The cases of intestinal infections were found in the population using the portable water of the standard quality in terms of E. coli, TDB, CCB, and enterococci. In this case only the wider integral index of GPB, which includes the indices of E. coli, TDB, CCB, as well as lactose-negative pathogenic and opportunistic species retains its sanitary significance in terms of all signs and is a reliable indicator of the potential epidemic hazard of drinking water use. Long-term studies have provided evidence for the sanitary value of coliphages as indicators of viral drinking water contamination.
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