Boundary Changes of Natural Plague Foci in the North-Western Pre-Caspian

Objective of the study is to specify present-day locations and sizes of natural plague foci in the North-Western Pre-Caspian.Materials and methods. Based on the results of field and office mapping of Pre-Caspian sandy and North-Western steppe plague foci, conducted in 2013–2014, designed have been electronic maps of the sectors, situated in the periphery of the foci.Results and conclusions. Detected has been marked reduction in sizes of natural foci owing to plowing of arid pastures. Over a significant distance, new natural focal boundaries are represented by linear elements of hydrography. Wherein such elements are absent, sector frames, in which evidence of enzooty remains, are accepted as formalized external boundaries. The process of deep and irreversible anthropogenic transformation of landscapes has resulted in the reduction of enzootic as regards plague territories: the steppe focus area has decreased by 22 %, being 51152 sq. km, the sandy one – by 13 %, amounting to 62510 sq. km. Farming on the extensive territories as a means of radical alterations of the landscapes has made the lands unsuitable for habitation of the little souslik, midday and tamarisk gerbils, which is an evidence of a complete loss of plague enzooty factors in the territory. The survey of actual position and sizes of natural plague foci within the rigid bonds, plotted on topographic maps and easily identifiable afield, provides for substantiated planning and complex prophylactic plague-control measures. Novel spatial parameters of the natural foci are suggested for the inclusion into official regulatory-methodological documents, guiding performance of epidemiological surveillance over plague

MODIFICATIONS TO THE BOUNDARIES OF THE NATURAL PLAGUE FOCI IN THE VOLGA-URAL INTERFLUVE

Objective of the study is to locate the present-day sites and sizes of the natural plague foci in the Volga-Ural Interfluve. Materials and methods. According to the results of the field and office mapping, 2015 in the Volga-Ural steppe and sandy plague foci, designed have been electronic maps of the sectors situated in the periphery. Results and conclusions. During the past 3–4 decades significant decrease in plague enzooties in the territory of the Volga-Ural Interfluve has been observed. It occurs due to the plowing and melioration of the grazing lands. It is established that the southern and south-western outskirts of enzootic territories have natural boundaries represented with the linear elements of hydrography, and the eastern ones are the state border of the Russian Federation and the Republic of Kazakhstan. At sites where suitable linear elements of the landscape are absent (up north and west) the frames of the sectors, where evidence of enzooty is retained, are used as the formal external boundaries. Widespread plowing of semi-desert area made the territories in the eastern part of the Volgograd Region inadequate for small souslik habitation, which marks the loss of plague enzooty features. This fact in its turn led to the reduction of steppe focus acreage by 30 %, the coverage being currently 20873 km2 . Configuration of the sandy focus changed little, if at all, and amounts to 8625 km2 . Registering of the actual position and sizes of natural plague foci within the strictly set boundaries put on topographic maps provides for targeted planning and complex prophylactic anti-plague measures. New spatial indicators of natural plague foci are formalized in official normative-methodological documents regulating epidemiological surveillance over plague

Role of Mosquitoes, <I>Culex</I> <I>pipiens</I> Complex, in West Nile Fever Virus Persistence in Urbanized Biocoenoses of Saratov

. In wiggler samples as well as in imago ones detected are WNF virus markers, which indicate the possibility of transovarial and trans-phase transmission of virus into mosquito populations, habitant in urbanized biocoenoses. It is substantiated that Culex pipiens female mosquitoes, which reproduce autogenically, provide for the persistence of the virus within the inter-epidemic period. Therewith there is a possibility of sustained, epidemically-active WNF micro-foci to be formed in the residential area landscapes, and this issue should be given proper consideration when performing assessment of the risks associated with urban population exposure to the infection

Management of Epizootiological Investigation in the Context of Mass Event (by the Example of the XXVII Worldwide Summer Universiade in Kazan, 2013)

In consequence of epizootiological investigation, differentiated has been Kazan territory according to the potential epidemic hazard levels; determined is the abundance of carriers and vectors of natural-focal infection agents in and around the territory of the Summer Universiade-2013; substantiated is the scope of preventive measures (disinfection, deratization, desinsection), as well as their frequency and coverage area. Timely detection of the regions with expressed epizootic potential growth has made it possible to carry out prophylactic activities and reach an epidemic-hazard-lowering effect as regards particular territories of the natural and anthropourgic infectious disease foci. Further on, validated has been disinfection as part of specific prophylaxis and as a basic measure for elimination of risks of the population exposure to natural-focal infections directly during the mass event

Conditions for Virus Circulation and Premises for Natural West Nile Fever Foci Formation in the Territory of the Saratov Region

Local climate change (rise of mean temperatures and amount of precipitation, prolongation of frost-free season) triggers further distribution, and increase in numbers of animals – carriers and vectors of West Nile fever virus in the territory of the Saratov region. Based on the results of ecological-epizootiological monitoring (2006–2012) traced out have been the species composition, abundance dynamics, and character of distribution of birds habitant in aquatic and anthropogenic complexes, mosquitoes and Ixodidae ticks. Investigated are possible causes of West Nile fever nosoarea expansion, related to ecology of migrating birds wintering in Africa. Persistent circulation of the virus in intra-zonal inundated biocoenosis facilitates formation of secondary natural foci of West Nile fever and factors into epidemic complications as regards this particularly dangerous vector-borne infection. On the basis of analytical data concerning hydrographic network density, fauna structure, population numbers of birds and mosquitoes – potential carriers and vectors of WNF, epizootiological and epidemiological surveillance, designed has been expectation-driven forecasting map chart which illustrates possibility of sustainable WNF foci formation in various territories of the Saratov region

Studies of West Nile Virus Circulation in the Territory of the Saratov Region in 2010

Presented are the results of ecological and epizootiological surveillance of the territory of the Saratov region, which was carried out in autumn of 2010. The surveillance was aimed at detection of West Nile (WN) virus circulation and premises for WN Fever natural focus formation. It is demonstrated that in 2010 WN virus circulation took place in damp biotopes of the Saratov region territory, and that common species of small mammals were involved in it. Presented are the results of analysis of the WN virus role in the infectious pathology in the territory of the Saratov region

Factors that Predetermined Activation of Plague Epizooties in the Pre-Caspian Sandy Natural Focus in 2014

In 2014, in the central coastal part of the Pre-Caspian sandy natural plague focus, activation of epizootic process in the complex rodent settlements occurred. Objective of the study was to identify the factors that predetermined the development of intensive and extensive plague epizooties. Utilized were operational data from the Astrakhan, Elista, and Dagestan plague control stations, and personal investigation records gathered in the focus. Consequently to the high baseline numbers of rodents and fleas, mild winter weather in 2013-2014 population density of the vectors and carriers of the infection significantly exceeded long-term average annual indexes in the following spring. Total abundance rates reached up to 31.1 specimens per a hectare, being lowered up to 17.8 by the fall. Stock of the main vector of plague, N. laeviceps flea, amounted to 350 and to 120 per a hectare in the spring and autumn, respectively. All in all, in the course of the three rolling seasons isolated were 56 Y. pestis cultures: 17 strains - from the rodents, and 39 - from the fleas. The overall epizootic area totaled to 2300 km2. Plague epizooties were registered in the zone of sustained natural focality within the bonds of the Ilmen-Pridelta, Primorsky, and Chernozemelsky landscape-epizootic regions in the administrative territory of the Limansky District in the Astrakhan Region, Lagansky and Chernozemelsky Regions of the Republic of Kalmykia, and Tarumovsky Region of the Republic of Dagestan. Results of monitoring over the epizootic manifestations and plague carrier and vector abundance dynamics provided the basis for scheduling and performance of anti-epidemic activities, as well as for forecasting of the epidemic situation development in the focus

Results of a Joint Epizootiological Survey of Transboundary Natural Plague Foci of the Russian Federation and Potentially Focal Territories of the Republic of Kazakhstan in 2019–2022

Consolidation of the efforts in implementation of epidemiological surveillance and control over plague and other dangerous natural-focal infections is an essential aspect in ensuring epidemiological well-being as regards particularly dangerous infectious diseases in the territory of natural plague foci and potentially focal territories located within the borders of the Russian Federation and the Republic of Kazakhstan. The aim of the work was to carry out a joint epizootiological survey of the transboundary territories of the Volga-Ural sandy natural plague focus and the territory of the East Kazakhstan region of the Republic of Kazakhstan (RK) potentially focal for plague over the period of 2019–2022. Materials and methods. Samples of field materials, collected during the epizootiological survey of the territory of Kazakhstan, were studied using bacteriological, molecular-genetic, and immune-serological methods. Results and discussion. We have obtained the current evidence on the spatial-biocenotic structure, the circulation of pathogens of dangerous natural-focal infectious diseases in the transboundary territories of Eastern and Western Kazakhstan. It has been established that the conditions that contribute to the possibility of human infection with plague and other dangerous infectious diseases in case of the aggravation of epizootic situation in the foci or importation of the pathogens into the territory are in place