Characterization and classification of strains of Francisella tularensis isolated in the central Asian focus of the Soviet Union and in Japan. (41/229)

The two subspecies of Francisella tularensis, F. tularensis subsp. tularensis (type A) and F. tularensis subsp. palaearctica (type B), differ from each other in biochemistry and virulence. Strains of F. tularensis subsp. tularensis are believed to be confined to North America, whereas strains of F. tularensis subsp. palaearctica occur in Europe, in Asia, and in North America. Moreover, the existence of two other subspecies, designated F. tularensis subsp. mediaasiatica and F. tularensis subsp. palaearcitica japonica, has been suggested for strains of F. tularensis isolated in the central Asian focus of the Soviet Union and in Japan, respectively. In the present study, strains biochemically classified as F. tularensis subsp. mediaasiatica or F. tularensis subsp. palaearctica japonica have been investigated by hybridization with probes specific to 16S rRNAs of the two main subspecies. Furthermore, the virulence and biochemical characteristics of the strains were compared with those of strains belonging to F. tularensis subsp. palaearctica and F. tularensis subsp. tularensis. It was found that 16S rRNAs of F. tularensis subsp. mediaasiatica and F. tularensis subsp. palaearctica japonica hybridize with the probe specific to a genotype proposed herein, genotype A (F. tularensis subsp. tularensis), which shows that strains genetically related to this subspecies are found outside North America. However, the central Asian strains differed from F. tularensis subsp. palaearctica and F. tularensis subsp. tularensis strains when investigated by fermentation of glucose. The results of the biochemical tests could not be unambiguously used for differentiation of strains into F. tularensis subsp. palaearctica or F. tularensis subsp. tularensis. These drawbacks suggest that classification of strains of Francisella on the basis of 16S rRNA analysis may be preferable to classification on the basis of biochemical analysis.  (+info)

AN APPRAISAL OF THE FLUORESCENT ANTIBODY METHOD IN GONORRHOEA. (42/229)

Fluorescent antibody procedures have in a short time become valued techniques for the detection of many pathogenic micro-organisms, and are used in syphilis, for instance. A fluorescent antibody test has also been proposed for use in gonorrhoea, but the author of this paper suggests that there are still many questions to be answered before that test can be recommended for widespread practical application. In particular, large-scale further research is necessary on the antigenic structure of Neisseria gonorrhoeae, and other organisms of the Neisseria group, before reliance can be placed on the strict specificity of this test.The author also describes the fluorescent antibody technique for gonorrhoea used in the USSR, discussing its advantages and disadvantages.  (+info)

METHODS OF LABORATORY DIAGNOSIS OF GONORRHOEA USED IN THE USSR. (43/229)

In this review of gonorrhoea diagnostic methods in current use in the USSR, the author stresses first the value of the examination of smears for the detection of the typical forms of the gonococcus. Where atypical L-forms are present, as may occur after treatment with antibiotics or sulfanilamide, microscopy may be misleading and a combination of laboratory methods is called for, including the use of culture techniques. Transport media for the maintenance of material for culture have been little used in the USSR so far, but experiments with the Stuart medium and modifications of it have shown promise.Although the complement-fixation test has lately fallen rather into disuse for gonorrhoea diagnosis, the author considers the inherent value of this serological method to warrant its further use provided that new and improved antigens and techniques can be developed capable of yielding specific reactions with both typical and atypical forms of the gonococcus.  (+info)

JAPANESE ENCEPHALITIS IN THE USSR. (44/229)

The author sketches the history of Japanese encephalitis in the USSR, where it has been thoroughly studied since it first occurred in 1938. After a brief outline of its epidemiology, he describes the pathogenesis, the signs and symptoms, and the pathophysiological mechanisms that make this form of encephalitis so dangerous. He also discusses the diagnosis and the methods of treatment and prevention practised in the USSR.  (+info)

TICK-BORNE ENCEPHALITIS IN THE USSR. (45/229)

The author gives the history of the study of tick-borne encephalitis in the USSR, following it up with a description of the etiological and epidemiological aspects and of the pathology, symptomology, diagnosis, treatment, and prevention of the disease. He stresses that other ticks as well as the main vectors of the virus, Ixodes, transmit the disease, in particular Dermacentor and Haemaphysalis. A detailed account of tick-borne encephalitis in the USSR may be of value in the study of the rather similar forms of the disease now being encountered more and more frequently in countries of South-East Asia as well as of northern and eastern Europe.  (+info)

SOME ECOLOGICAL ASPECTS OF THE PROBLEM OF ARTHROPOD-BORNE ANIMAL VIRUSES IN THE WESTERN PACIFIC AND SOUTH-EAST ASIA REGIONS. (46/229)

In recent years there has been an increasing awareness of the importance of arthropod-borne viruses in the Western Pacific region and in South-East Asia. This realization of the importance of these viruses as causes of human morbidity and mortality and of economic loss due to infection of domestic animals has led to studies attempting to elucidate the basic ecology of some of these viruses. The author reviews the extent of knowledge of the ecology of Japanese and Murray Valley encephalitis viruses and indicates possible mechanisms for the overwintering of the viruses based on experiments in which other viruses were mainly used. He discusses the limited available knowledge on the ecology of dengue and emphasizes the necessity of research on the possibility that this disease is a zoonosis. A brief discussion is also given of the haemorrhagic diseases which are found in these regions and a brief description of the state of knowledge on the ecology of Kyasanur Forest disease and epidemic nephroso-nephritis. A brief discussion is also included on the ecology of the tick-borne Russian spring-summer encephalitis.  (+info)

SOVIET NEUROLOGICAL SCIENCE TODAY. (47/229)

Neurological sciences in the U.S.S.R. are healthy but have middle-age spread, as judged from an intensive personal tour of facilities as a guest of the Soviet Academy of Sciences during the autumn of 1963. Many of the recent Western enthusiasms in ultrastructure, cytogenetics and molecular genetics appear not to have inflamed many imaginations. However, Soviet neurologists are contributing to the same types of electrophysiological research as are current in the West. The full realization of the talents of many well-trained young investigators is hindered by the strong emphasis on Pavlovian theory and technique, the rigid multi-layered structure of research institutes, and the relative isolation from undergraduate medical schools of most research.  (+info)

RESULTS OF THE STUDY OF TYPHOID VACCINES IN FOUR CONTROLLED FIELD TRIALS IN THE USSR. (48/229)

In field trials of typhoid vaccine in the USSR, a comparison was made of the effectiveness of chemical, heat-killed, and alcoholized vaccines. All of them conferred protection if administered in sufficient dosage, and variations in effectiveness could usually be traced to size of dosage. The heat-killed vaccine, however, appeared to be significantly more effective than the others. The immunological history of a vaccinated person apparently had no essential influence on the effectiveness of a vaccine, and the data indicated that two doses of the vaccine conferred no greater protection than one.  (+info)