Epizootic Activity Of Natural Foci Research Articles

Assessment of the epizootic activity of natural foci of zoonotic infections and their epidemiological manifestations in the territory of the Kyrgyz Republic

Assessment of the epizootic activity of natural foci of zoonotic infections and their epidemiological manifestations in the territory of the Kyrgyz Republic

Epidemiological Situation on Plague in 2020. Forecast of Episootic Activity of Natural Plague Foci in the Russian Federation and Other CIS Countries for 2021

The aim of the work was to substantiate the forecast of the epidemiological and epizootiological situation in natural foci of plague in the Russian Federation, countries of the near and far abroad for the year of 2021. Characteristics of the distribution of Yersinia pestis strains of the main subspecies (subspecies pestis) of medieval and antique biovars, Caucasian (ssp. caucasica) and central Asian (ssp. central asiatica) subspecies by 45 natural foci of the CIS countries are presented in the paper. The persistence of a multidirectional trend in the dynamics of epizootic activity of natural foci of the CIS countries with the circulation of Y. pestis pestis strains of the medieval biovar of the 2.MED1 phylogenetic branch and the antique biovar of the 0.ANT5, 4.ANT phylogenetic branches in the current decade has been outlined. For the Russian Federation, the development of epizootics is predicted in the Gorno-Altai highland and Tuva mountain natural foci caused by the circulation of Y. pestis pestis strains of the antique biovar 4.ANT and Y. pestis of the Altai biovar of the Central Asian subspecies 0.PE4a in 2021. For the Republic of Kazakhstan, there is a high probability of preserving epizootic activity in the North Aral, Aral-Karakum, Balkhash, Mojynkum, Taukum desert and Ili intermountain natural foci with the circulation of Y. pestis pestis strains of the medieval biovar of the phylogenetic branch 2.MED1. For the Kyrgyz Republic, the forecast for the development of plague epizootics caused by Y. pestis pestis strains of the antique biovar 0.ANT5 phylogenetic branch in the Sarydzhaz and Upper Naryn high-mountain natural foci has been substantiated. A high epidemic risk of epizootic manifestations caused by highly virulent strains of Y. pestis pestis of antique biovars 0.ANT5, 4.ANT and medieval biovar 2.MED1 for the entire territory of the CIS countries is noted. The relevance of implementing forecasts of the epidemiological situation into practice, taking into account the molecular-genetic and epidemiological characteristics of Y. pestis strains circulating in areas of expected epizootic manifestations of plague, is highlighted.

Epidemiological Situation on Tularemia in the far Eastern Federal District (2000-2017)

Relevance Tularemia - natural focal zoonotic infection occupies an important place in the structure of human infectious pathology. The incidence is associated with natural foci, where there are favorable conditions for the existence of the pathogen, its circulation among rodents and other mammals. Natural foci of tularemia are widespread and are characterized by high environmental plasticity of the pathogen, which has polyhostality, polyvector, a plurality of transmission mechanisms, the duration of preservation of the pathogen in the external environment, especially at low temperatures, as well as the hydrophilicity of the pathogen and the ability to experience adverse conditions in a resting (uncultivated) form. Tularemia is a particularly dangerous infection, is included in the second group of pathogenicity. Aims. The purpose of this work is to identify the main patterns of functioning and epidemic manifestations of natural foci of tularemia in the far Eastern Federal district (far Eastern Federal district) on the basis of long-term monitoring and using various research methods. Results, The analysis of the epizootic state and epidemic manifestation of natural foci of tularemia in the territory of the far Eastern Federal district for 2000-2017 shows that the main regularities of the epidemic process remain in the natural foci of this infection. Given the nature of the epidemic manifestations of tularemia, due to different ways of infection, seasonality, vaccination, etc., it is necessary to improve the system of epidemiological surveillance of the state of natural foci of infection and develop a differentiated approach to the prevention of tularemia. The analysis revealed the dynamics of epizootic activity of natural foci of tularemia, confirmed by the release of cultures of the pathogen and positive serological findings of antibodies and antigen, and in recent years, DNA Francisella tularensis in biological objects. For the first time, a retrospective diagnosis of 249 serum tularemia of people living in the regions of the Kamchatka region and the Koryak Autonomous district was made, which made it possible to identify among the local population those who had been ill with tularemia at different times, which indicates the presence of natural foci of this infection. In the Khabarovsk territory and the Amur region, mixed infection of patients with two natural focal infections was revealed: tularemia - hemorrhagic fever with renal syndrome, tularemia - tick rickettsiosis. Thus, there is a possibility of simultaneous or consecutive infection of people with two, and possibly more natural focal infections in combined foci. Eleven years of observation of natural foci of tundra tularemia not subjected to anthropogenic and man-made impact on the island of Wrangel allowed to establish their epizootic activity, which is an epidemic danger for contingents traveling to temporary work in the areas of the island. Conclusions Analysis of the epidemic manifestations of natural foci of tularemia on the territory of the far Eastern Federal district in recent years has shown that immunization of the population living in enzootic areas for this infection is not carried out in full, and in some subjects is completely absent. Reducing the incidence of tularemia as a result of vaccination does not mean the recovery of natural foci, the potential danger of which continues to persist.

CHARACTERISTICS OF NATURAL FOCI OF TULAREMIA IN THE CRIMEA, THEIR POTENTIAL DANGER IN THE DEVELOPMENT OF THE EPIDEMIC PROCESS AND THE MAIN DIRECTIONS OF ITS PREVENTION

Geographical and climatic conditions of the Crimean peninsula, mammals of a particular ecosystem together with pathogens of the infection and a complex of their ectoparasites, contribute to the preservation of natural foci of tularemia and other natural focal infectious diseases on its territory. Epizootic activity of natural foci of tularemia has a welldefined periodicity and seasonality. Currently, natural foci of tularemia of the steppe type in the flat Crimea and forest type on the territory of the mountain-forest Crimea function. Three types of enzootic tularemia were identified. The epidemiological analysis of people with tularemia in the Crimea showed that its dynamics, level and distribution of cases in the administrative regions are determined primarily by the activity and duration of epizootics in natural foci located in the territories where tularemia is diagnosed. Prevention of diseases of people with tularemia in the Crimea, requires constant monitoring of the activity of natural foci of these infections, the timely detection of rodent epizootics, the study of their ectoparasites and their results, and the implementation of preventive measures.

Современное состояние природных очагов опасных инфекционных болезней на территории Республики Татарстан

Objective of the study is to evaluate the current state of epizootic activity of natural zoonotic foci, as the basis for the development of prophylactic measures aimed at prevention of natural-focal infections during mass events. Materials and methods. Utilized have been reports from the Center of Hygiene and Epidemiology in the Republic of Tatarstan, the data provided by Rospotrebnadzor Administration in the Republic of Tatarstan over the period of 2009-2014, and literature references. Results and conclusions. The most pressing natural-focal infectious diseases are hemorrhagic fever with renal syndrome, tick-borne borreliosis, and tick-borne viral encephalitis. Yersinioses, leptospiroses, and West Nile fever are rarely registered. Tularemia infections have not been reported within the past 20 years. The period of 2009-2013 is characterized by the decrease in the numbers of carriers and vectors of the diseases, as well as epizootic activity of natural foci, which came up to minimum values in 2013. Emerged since 2014 increment in the abundance rates of the carriers and later the vectors can lead to the increase in the incidence of natural-focal diseases. In the territory of the Republic, allocated are the spatial combination areas of natural foci of the diseases of various etiology with high risk of population exposure. Previous to conduction of mass events it is necessary to enhance the epizootiological surveillance in the natural foci, the results of which lay premises for the development of complex prophylactic activities.

EPIDEMIOLOGIC SITUATION BY NATURAL-FOCI INFECTIONS IN THE CRIMEA FEDERAL DISTRICT IN 2014 - 2015

Analysis of epidemic manifestations of natural-foci infections (NFI), clarification of spectrum of their causative agents, determination of epizootic activity of natural foci in the Crimea Federal District (KFD). Epizootologic examination of 10 administrative districts of KDF was carried out. 291 pools (2705 specimens) of ixodes ticks and 283 samples of organs of small mammals were studied by PCRmethod for the presence of DNA/RNA of causative agents of a number of NFI. Morbidity by NFI in KFD was registered by 6 nosologies: Lyme borreliosis, Marseilles fever, leptospirosis; tularemia, intestine yersiniosis and tick-borne viral encephalitis, wherein, transmissive infections made up 91.6%. Circulation of causative agents of Crimea hemorrhagic fever, Q fever, group of tick-borne spotted fever, Lyme borreliosis, human granulocytic anaplasmosis, human monocytic ehrlichiosis, hemorrhagic fever with renal syndrome, West Nile fever, tularemia and leptospirosis was established. Due to activity of natural foci of NFI further monitoring of epidemiologic and epizootologic manifestations of these infections in the Crimea, including using genetic methods of analysis, is necessary for ensuring sanitary-epidemiologic welfare of KFD population.

Ecology of Yersinia pestis and the Epidemiology of Plague.

This chapter summarizes information about the natural foci of plague in the world. We describe the location, main hosts, and vectors of Yersinia pestis. The ecological features of the hosts and vectors of plague are listed, including predators - birds and mammals and their role in the epizootic. The epizootic process in plague and the factors affecting the dynamics of epizootic activity of natural foci of Y. pestis are described in detail. The mathematical models of the epizootic process in plague and predictive models are briefly described. The most comprehensive list of the hosts and vectors of Y. pestis in the world is presented as well.

Interdependence between Epizootic Activity of Natural Foci of Hemorrhagic Fever with Renal Syndrome (HFRS) and Epidemiological Situation in the Ulyanovsk Region

Based on the results of retrospective analysis of HFRS morbidity and epizootiological data on the numbers and contamination of mouse-like rodents, revealed has been epidemic potential shift of the HFRS foci. It requires reconsideration of the scope, format, and objectives of preventive and anti-epidemic activities. Periodicity of fluctuations in the numbers of small mammals, habitant in the territory of the Ulyanovsk Region, makes up three years on average. Since 2011 up to 2013 generalized depression in the abundance rates was observed. The period was marked by the reduction of the segment of main Hantavirus carrier - common red-backed vole. It was the key factor for epidemic process activity decrease, which in its turn resulted in the decrease of morbidity rates among the population. Therewith, the transformations that affect the population of mouse-like rodents are the determinative factors in the evolution of epidemic process which shapes epidemiological situation on HFRS in the territory of the constituent entity.

Epizootic Activity of Natural Plague Foci in the Russian Federation in 2013 and Prognosis for the Year of 2014

Analyzed are the data of the epizootiologic survey of plague enzootic territories in Russia in 2013. Evaluated are the numbers of major carriers and vectors as well as the epizootic activity of natural foci of different types. Analysis of preconditions for decrease of epizootic potential of plague natural foci of Caucasus, Altai and Tyva is carried out. Single findings of infected fleas are registered at the sites of steady focality in the territory of Pre-Caspian lowland. Forecast of epizootic situation for 2014 is presented. Marked is raising probability that Volga-Ural sandy and Central Caucasian high-mountain plague foci would get out of the inter-epizootic period state. Substantiated are the possibility of plague epizootics continuation and their intensity in Pre-Caspian sandy, Altai and Tyva mountain, and Eastern-Caucasus high-mountain plague natural foci.

Epizootic Activity of Natural Plague Foci in the Russian Federation in 2012 and Prognosis for the Year of 2013

Integrated are the data on the number of major carriers and vectors as well as the epizootic activity of natural foci of plague of different types in the territory of Russia in 2012. Submitted is the short-term forecast of epizootic situation for 2013. Analyzed are the reasons of current low epizootic activity of plain natural foci of plague. The role of climatic factors in the development of long inter-epizootic periods in plague natural foci in the Pre-Caucasus, Pre-Caspian regions and Siberia is discussed. Assessed is the change of potential epidemiologic hazard of plague-enzootic territories under the current warming of climate. The long-term forecast of epizootic activity of natural plague foci for the period of up to 2020 is substantiated.