There is evidence that in 1923-2014 the sharp aggravations of the epizootic situation of plague in the area of its Caspian sandy natural focus after long interepizootic periods are in time with the ups of the Caspian Sea in the extrema of 11-year solar cycles. There were cases of multiple manifestations of plague in the same areas in the epizootic cycles of 1946-1954, 1979-1996, 2001, and 2013-2014. The paper considers the possible role of amebae of the genus Acanthamoeba and nematodes, the representatives of the orders Rhabditida and Tylenchida in the microfocal pattern of plague manifestations.

AIM:Examine features of natural, natural-anthropourgic and anthropourgic foci of hemorrhagic fever with renal syndrome (HFRS) in various, mostly forest, biotopes of typical barrens due to differences of non-specific HFRS prophylaxis in foci of various types.MATERIALS AND METHODS:Epizootological and epidemiologic data from 1998 to 2012 were analyzed, gathered in HFRS foci of all types in Saratov area of Saratov Region (typical barrens). 14,606 trap-nights were worked off and 2669 small mammals were procured. The most significant population-ecologic and ecologic-epizootological methods and criteria were used for comparative analysis of differences for 3 types of foci.RESULTS:Based on analysis of multi-year data seasonal differences for HFRS foci of various types were shown by 10 population-ecologic and ecologic-epizootologic criteria.CONCLUSION:The results obtained allow to state that modern means and methods of non-specific prophylaxis of HFRS and other zoonoses in foci of various types different significantly. This allows the most rational use of material and financial resources.

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.

Analyzed are the data on the state of the carrier populations (abundance rates, distribution by stations) across constituent entities of the Russian Federation in 2014 as compared to the previous period. On the whole abundance of small mammals has not exceeded the long-term average annual values. For each of the 9 Federal Districts given has been an estimation of epizootic and epidemic activity in the natural tularemia foci in 2014. Outlined is a sharp decrease in tularemia morbidity in comparison to 2013. It is determined that within the past two decades there has occurred three major incidence outsurges in 1995, in 2005, and 2013, respectively. Based on the information obtained made has been the forecast for the development of epidemiological situation in natural tularemia foci of various types. Against the background of sharp decrease in the morbidity rates consequent upsurges are registered at certain intervals of several years, nevertheless current volatile state of ecosystems may draw a mixed response of parasitic systems.

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.

Climate changes determine dynamics of epizootic activity of natural plague foci in the XX and XXI centuries. Obvious shift to continentality in the Northern hemisphere can put an end to inter-epizootic period in lowland steppe and semi-desert natural foci of the Pre-Caucasian region, North and North-West Caspian Sea regions. Presently observed conjoined development of inter-epizootic periods in natural plague foci with different biocoenotic structure in the territory of Pre-Caspian Lowland gives the grounds for assuming the presence of a common cause preconditioning parasitic system depression in the region. One of the key elements of this phenomenon is a change of status of little souslik – formerly the main plague carrier in the region. Subsequent to the climate change the key role of plague carrier is more often played by non-hibernating rodent species nowadays. Thus a significant increase in epizootic potential of steppe natural plague foci in the territory of Kazakhstan and Central Asia is prognosticated. With the further temperature fall during wintertime, snow cover height increase and glacial area extension epizootic activity of the mountain and high mountain foci must drop off significantly. Alongside with this updated data on plague agent ecology, predetermining possibility of its existence in the soil biota, confirm the key role of climactic factors in the plague enzootic outbreak.

Shown was the influence of modern day warming and some other factors on natural plague foci of the European South-East of Russia. Analyzed were the basic mechanisms of transformation of biocenotic structure of natural foci complexes. It was shown that the tendency of gradual change of dominant carriers species would be preserved due to further warming of climate. As a result, the expansion of polyhostal natural foci of plague of semidesert type would be continued.

AIMEstablish the main reasons of low epizootic activity of natural foci of plague in Russian Federation in 2000-2009.MATERIALS AND METHODSMultiyear data on the number of isolated Yersinia pestis strains, area of detected epizootic sites, amounts of the field material studied for plague were used to evaluate annual activity of natural foci.RESULTSIn the current decade mountain and high-mountain natural foci of plague were characterized by constant high epizootic activity. In plains and low-mountain natural foci a low periodic epizootic activity was noticed, a development of intra-epizootic periods. A conditioning role of helioclimatic factors on the status of parasitic systems and epizootic activity of natural foci of plague was noticed.CONCLUSIONThe warming of climate in 1990-2007 was the main reason for low epizootic activity of plains natural foci of plague in Russia. In the contemporary conditions of a recurrent cooling (from 2008) and an increase of humidity in the Northern, North-Western pre-Caspian and pre-Caucasus territories, a new significant activation of them is predicted there with a peak in 2017-2019.

The results of epizootiological surveillance in 11 plague natural foci in the territory of the Russian Federation in 2010 are presented in this review. The short-term prognosis of foci epizootic activity is performed based on the analysis of data on epizootic activity, the conditions of plague carrier and vector populations, and abiotic factors influence on their living conditions.

Short-term prognosis of epizootic activity of 11 natural plague foci in Russia for 2010 is substantiated. The analysis of the main plague carries and vectors abundance in natural foci of different types was carried out. Determined were the modern tendencies of the dynamics of epizootic activity of natural plague foci with different biocenotic structure.

The paper analyzes relationships of the plague bacilli to the representatives of different types of living organisms inhabiting the burrows. The authors give their own data on the qualitative and quantitative composition of indicoles of the burrow of little sousliks (Spermophillus pygmaeus). They assess the role of mutagenic agents in burrow microbiocenoses.

Presented are the field trial results of mobile laboratory in the forest-steppe, steppe and semi-desert regions in autumn and winter periods.

A short-term prognosis of plague epizootic activity in 11 natural foci in the Russian Federation for 2009 is substantiated by the authors. The present situation with the numbers of the main carriers and vectors of plague infection in diverse types of natural foci was analyzed. Some modern tendencies were noted in the dynamics of epizootic activity of the natural plague foci varying in their biocenotic structures.

The development of two deep depressions in the numbers of small sousliks, observed in the 50ths - 60ths and 80ths - 90ths of the twentieth century, was shown to be significantly contributed to by the climatic factors in the North-Western Pre-Caspian region. The important role of the present-day climate warming upon the evolution of the inter-epidemic period in the North-Western Pre-Caspian steppe natural plague focus was ascertained, too. Search for Yersinia pestis strains in the rodent burrows soil in the areas of stable plague manifestations was recognized as a perspective surveillance measure to be practiced.

The modern boundaries of distribution of tamarisk gerbil - Meriones Tamariscinus (Pallas, 1773) were determined in the territory of the republic of Kalmykia. Shown was the role of irrigation and watering of the land in the expansion of its natural habitat to the north and north-west. Epizootiologic and epidemiologic consequences of tamarisk gerbil settling in the territory of Pre-Caspian North-Western steppe natural focus of plague were considered. The tendency of formation of the integrated plague natural focus of the gerbil type in the North-Western Pre-Caspian region and Ciscaucasia was confirmed.