Development of a Reagent for Evaluation of Incipient Immune Response to the Live Plague Vaccine

Objective of the study is to develop a reagent for the detection of lymphocytes with Yersinia pestis F1 antigen receptors. Materials and methods. Utilized have been: live plague vaccine based on the strain of Yersinia pestis EV NIIEG, formalin killed suspensions of microorganisms - Y. pestis , 3123, Y. enterocolitica O9 H-383 serovar, Y. pseudotuberculosis O1 2841 serovar; acetaldehyde-immobilized capsular antigen of Y. pestis F1 (obtained applying Baker methodology), lipopolysaccharide of Y. pestis K1, and bovine erythrocytes. Bovine erythrocyte F1 sensibilization has been performed using rivanol. Lymphocytes from blood have been isolated in density gradient ficoll-verografin 1.077. Lymphocytes with Yersinia pestis F1 antigen receptors have been detected by means of reagent adhesion onto the isolated lymphocytes. F1-free erythrocytes serve as controls. After the exposition, 7 evaluations of specificity to F1 and the lymphocytes, binding control reagent, have been carried out. Deployed have been 8 rabbits, immunized with live vaccine EV, and 2 rabbits, immunized with inactivated vaccine EV. Examined have been EV-vaccinated 5 persons. Results and conclusions. Identified is optimum sensibilizing dose of F1 antigen (250 µg/ml). Specificity of lymphocytes with receptors to F1 is demonstrated in inhibition experiments applying homologous and heterogeneous antigens. Lymphocytes with receptors to F1 (LRs) have been detected in peripheral blood of all rabbits and humans, immunized with vaccine EV. LRs have been registered since day 2 till day 35 in the rabbits, and in humans - since day 2 till day 14 after vaccination. It is shown that in case of revaccination of humans, LRs emerge and disappear earlier, than in case of primary immunization

Plague: past, present and future

[Introduction] Recent experience with SARS (severe acute respiratory syndrome) [1] and avian flu shows that the public and political response to threats from new anthropozoonoses can be near-hysteria. This can readily make us forget more classical animal-borne diseases, such as plague (Box 1). Three recent international meetings on plague (Box 2) concluded that: (1) it should be re-emphasised that the plague bacillus (Yersinia pestis) still causes several thousand human cases per year [2,3] (Figure 1); (2) locally perceived risks far outstrip the objective risk based purely on the number of cases [2]; (3) climate change might increase the risk of plague outbreaks where plague is currently endemic and new plague areas might arise [2,4]; (4) remarkably little is known about the dynamics of plague in its natural reservoirs and hence about changing risks for humans [5]; and, therefore, (5) plague should be taken much more seriously by the international community than appears to be the case

Brief space and time characteristics of epizootic plague situation in Kazakhstan in 2011

The natural plague foci of Kazakhstan occupy a huge territory. The mapping of these foci is a very important part of the plague monitoring and has a scientific and practical meaning. The old paper mapped data have been obsolete and. all previous and. current data have been digitized now. The digitizing of the data was carried by ArcGIS program. The epidemiological and epizootological analysis of the data of 2012 showed that the Kazakh plague natural foci were active in that time. And the analysis showed that by the complex factors a more active and epidemic hazardous area was Qyzylorda Region

Morphological, Physiological and Genetic Characteristics of Populations of the Main Plague Host Rhombomys opimus Licht., 1823 in the Central Asian Desert Natural Focus of Plague

Revealed by morphological characters, physiological status, and genetic diversity of populations of the main plague host Rhombomys opimus Licht., 1823 in Central Asia desert natural focus is described.Differences in the skull parameters of R. opimus from different populations were revealed. It’s shown that gerbils from Moyunkum are separate autonomous populations group. Samples from Moyunkum and Mangyshlak differed from other samples. In Balkhash-Alakol depression found two regional complexes: Pre-Balkhash and Dzungarian.Study results of free amino acids level in R. opimus blood serum obtained by gas-liquid chromatography of blood sera from animals captured in different zones of Central Asian focus gave statistically significant differences. To determine genetic variability in ecological and geographical isolation of R. opimus populations the DNA was genotyped.DNA samples analysis combined the studied gerbil from the desert focus into four clusters with eighteen haplotypes. R. opimus sequence analysis taking into account data from territories of Iran, Kazakhstan and China, clustered into three large clusters. First cluster combined the sequences of Kazakhstan and China samples, while great gerbil captured in Kazakhstan is located in a separate treasure. Second and third clusters include sequences of a great gerbil captured in Iran

THE EPIDEMIOLOGICAL SITUATION ON CHOLERA IN THE REPUBLIC OF KAZAKHSTAN IN 2011

The analysis of registered cholera cases that occurred during 1993-2008 showed that all epidemic cases of cholera in Kazakhstan were imported. The toxigenic cholera microbes were isolated from the water reservoirs which started in the neighbor country. The spatial distribution of non-toxic cholera vibrio has the regional features. The climatic and anthropogenic factors affect the distribution of the cholera vibrio in the Kazakhstan. The results of the analysis show that the complex approach has to be used for cholera epidemiological monitoring

Analysis of epidemiologic situation of cholera in 2012 in Kazakhstan

In the world the tendency of growth of cholera cases has been increasing. In Kazakhstan in 2011 epidemic cholera strains were isolated from the environment. In 2012 the cholera situation was quite stable. The cholera strains were isolated from the environment. Strains V. cholerae non O1 were isolated from people. But all isolated strains were not hazardous. By the complex of factors the South. Kazakhstan. Region is more cholera unfavorable region in Kazakhsta

Mapping the distribution of the main host for plague in a complex landscape in Kazakhstan: an object-based approach using SPOT-5 XS, Landsat 7 ETM+, SRTM and multiple random forests

Plague is a zoonotic infectious disease presentin great gerbil populations in Kazakhstan. Infectious disease dynamics are influenced by the spatial distribution of the carriers (hosts) of the disease. The great gerbil, the main host in our study area, lives in burrows, which can be recognized on high resolution satellite imagery. In this study, using earth observation data at various spatial scales, we map the spatial distribution of burrows in a semi-desertlandscape

Plague metapopulation dynamics in a natural reservoir: the burrow system as the unit of study

The ecology of plague (Yersinia pestis infection) in its ancient foci in Central Asia remains poorly understood. We present field data from two sites in Kazakhstan where the great gerbil (Rhombomys opimus) is the major natural host. Family groups inhabit and defend burrow systems spaced throughout the landscape, such that the host population may be considered a metapopulation, with each occupied burrow system a subpopulation. We examine plague transmission within and between family groups and its effect on survival. Transmission of plague occurred disproportionately within family groups although not all gerbils became infected once plague entered a burrow system. There were no spatial patterns to suggest that family groups in close proximity to infected burrow systems were more at risk of infection than those far away. At one site, infection increased the chances of burrow-system extinction. Overall, it is useful to consider the burrow system as the unit of study within a much larger metapopulation

Mapping the distribution of the main host for plague in a complex landscape in Kazakhstan: An object-based approach using SPOT-5 XS, Landsat 7 ETM+, SRTM and multiple Random Forests

Plague is a zoonotic infectious disease present in great gerbilpopulations in Kazakhstan. Infectious disease dynamics are influenced bythe spatial distribution of the carriers (hosts) of the disease. Thegreat gerbil, the main host in our study area, lives in burrows, whichcan be recognized on high resolution satellite imagery. In this study,using earth observation data at various spatial scales, we map thespatial distribution of burrows in a semi-desert landscape.The study area consists of various landscape types. To evaluate whetheridentification of burrows by classification is possible in theselandscape types, the study area was subdivided into eight landscapeunits, on the basis of Landsat 7 ETM+ derived Tasselled Cap Greennessand Brightness, and SRTM derived standard deviation in elevation.In the field, 904 burrows were mapped. Using two segmented 2.5 mresolution SPOT-5 XS satellite scenes, reference object sets werecreated. Random Forests were built for both SPOT scenes and used toclassify the images. Additionally, a stratified classification wascarried out, by building separate Random Forests per landscape unit.Burrows were successfully classified in all landscape units. In the‘steppe on floodplain’ areas, classification worked best:producer's and user's accuracy in those areas reached 88% and 100%,respectively. In the ‘floodplain’ areas with a moreheterogeneous vegetation cover, classification worked least well; there,accuracies were 86 and 58% respectively. Stratified classificationimproved the results in all landscape units where comparison waspossible (four), increasing kappa coefficients by 13, 10, 9 and 1%,respectively.In this study, an innovative stratification method using high- andmedium resolution imagery was applied in order to map host distributionon a large spatial scale. The burrow maps we developed will help todetect changes in the distribution of great gerbil populations and,moreover, serve as a unique empirical data set which can be used asinput for epidemiological plague models. This is an important step inunderstanding the dynamics of plague