Ecosystem Dynamics and Prophylaxy of Natural Foci Diseases
Estimating Ecosystem Dynamics as a Basis for Elaborating of Actions on Preventive Measures for Natural Foci Diseases (Plague, Hemorrhagic Fever with Renal Syndrome etc.)
Tech Area / Field
- MED-DIS/Disease Surveillance/Medicine
- BIO-SFS/Biosafety and BioSecurity/Biotechnology
- ENV-EHS/Environmental Health and Safety/Environment
3 Approved without Funding
Russian Academy of Sciences / Severtsov Institute of Ecology and Evolution, Russia, Moscow
- United States Department of the Interior / U. S. Geological Survey, USA, VA, Reston\nUniversity of Wisconsin Oshkosh, USA, WI, Oshkosh\nCarnegie Museam of Natural History, USA, PA, Rector
Project summaryThe goal of the project: in accordance with the principles of the sustainable development and the rational use of the natural resources to develop a system of monitoring and regulation of the human impact on the natural foci of plague and hemoerrhagic fever with renal syndrome (HVF) considering specifics of the local ecosystem dynamics under human impacts, and to suggest recommendations for the non-specific prophylaxis in reclamation zones inclusive of the population and ecological patterns of the small mammals host species and their response to the environmental change.
The human impact on natural landscapes has been steadily increasing during the last decades. The number of man-caused disasters is dramatically increased: blowout of ecotoxicants in atmosphere, dramatic and usually irreversible violation of forest and steppe ecosystems as result of clean cuttings and overgrazing, military activity and other forms of human impacts on natural resources. Nowadays the alternative to the former commercial using of natural resources is science substantiation for exploitation of environmental systems taking into account preventing their destruction and considering possibility of reestablishing of ecosystems in relation with the specifics of natural regions, biotic persity and population organization of the mass species. Now, principles of sustainable development based on the conservation of biological resources and rational land-use are recognized by policy-makers as key components of the national security systems in many countries. Hence, a need for estimating the present status and man-made dynamics of natural foci of infections and for development of new approaches to infections prophylaxis based on the explicit prognosis, monitoring and effort localization in accordance with up-to-date economical and conservation principles emerges.
Our previous findings indicated a strong need for the constant monitoring of the natural disease foci under the dynamic environmental change. Vital need for the further development and extending of the monitoring stems from the non-equilibrium state of the natural ecosystems under unstable human impact, which makes it difficult to predict the status of the natural foci of infections. In this project the major efforts should be aimed at working out the program of the rational land-use and regulation of agricultural and man-made impacts in the first place. Together with the commonly recognized principles of the sustainable development new approach to the resource exploitation within territories of the natural foci of infections must take into account specifics of the host species population response to the environmental change.
The approach to the monitoring of ecosystems and population characteristics of the plague hosts in varying environment under the human impact developed on the project can be applied to the natural foci of other than plague infections and to the different landscapes that suffer pressure of human activities. Till recently the specifics of the host species population response to the environmental change as a factor influencing the intensity of infection circulation in nature is poorly understood. The epizootic process is regulated to a large extent by just population characteristics, such as stress level, spatial distribution, social systems and behavior, immune status. The common use of burrows by rodents support parasite exchange. Wide ranging and dispersal facilitate horizontal dissemination of infectious agents. On the contrary, rodents territoriality (territory defense) prevent agent invasion in patches with the dense rodent population. Tendency to penetrate human buildings significantly increases risk of infection. Stress effects on the host species populations alters hormonal status and reduces the immune reactivity. The spatial distribution and the population dynamics of the primary hosts produce direct effects on epizootic development and risk of contamination.
Population characteristics are very sensitive to the environmental changes. In areas under the man-made disturbances migration rates and ranging of rodents may increase; construction of communications and viaducts favors host species dispersion. Ecosystem disturbances affect the rodent species composition and population structure, numbers and distribution. Man-made disasters may undermine small mammal populations, but the survived part of population appear to be resistant to the negative impacts and reproduce at unusually high rates. Thus, one may expect that changes in the population characteristics under the influence of the environmental disturbances may alter epizootic or epidemic situation. However, till now this particular aspects remain unclear and are not taken into consideration when developing programs of land-use and regulations of exploitation of the biological resources.
Till now among infections circulating in the wild in Old and New World plague and HVF constitute a real menace to the human population. Rodent host species of these dangerous infections are well known; their biology, population dynamics in stable ecosystems and their effects on epizootic development are relatively well studied. However, data on the key population characteristics determining epizootic intensity in disturbed landscapes are lacking. Recognition of such patterns in the natural foci of plague in open steppe and semi-desert ecosystems and in natural foci of HVF in forest ecosystems may serve as a model for further development of methods to predict activation of the natural foci in other disturbed landscapes.
Open semi-desert and steppe landscapes where the natural plague foci persist are very sensitive to the disturbing factors, which as recognized by the World Conservation Monitoring Center (WCMC) may cause the rapid and catastrophic irreversible changes of the ecosystems or their components (IUCN, 1998). Many natural infections as plague above all are distributed within an area occupied by open steppe and semi-desert landscapes.
The forest ecosystems of taiga in European part of Russia fall into principally different category of landscapes in respect to sensitivity to the disturbing factors. Restoration process after overexploitation or man-made disturbances takes more time than in steppe or semi-desert ecosystems. Permanent exploitation of the forest zones resulted in formation of mosaic of habitats determining high extent of the environmental heterogeneity which may influence patterns of HVF epizootic process and epidemic outbreaks. Thus, different sensitivity and reactivity of semi-desert and forest zones to the environmental disturbances may determine different patterns of the natural foci disease transformation and dynamics under varying human impact and, consequently, different requirements to the development of programs of the wise using of land inclusive of demands for the preventive measures of disease control in reclamation areas.
Applying of the non-specific prophylactic measures such as rodent population control that ignores population response by the rodent host species cannot provide significant lowering of the morbidity rate. Direct population suppression by chemicals can stimulate mobility and reproduction of rodents, which in turn determines high risk of epidemics, and suppresses immune status provoking acute epizootic in small mammals. Finally, existing systems of the non-specific prophylaxis do not consider dynamic status of the ecosystems and the possibility of their abrupt and sometimes unpredictable changes as a result of the altered man-made pressure.
The suggested project serves the purposes of ISTC and extends the implementation of the objectives of the Center. The participation of the former "weapon specialists" allowed them to apply their previous skills in civilian sphere and to incorporate their experience into international science. New contacts with specialists from abroad were established at the current stage, and the development of the project will permit to strengthen bonds and to extend cooperation with foreign specialists (from USA). The project meets the requirements of the fundamental and applied issues in the field of the environmental conservation and corresponds to the principles of the sustainable development and wise using of land. The development of the nature protective system of the natural disease prophylaxis based on the acquired knowledge about the ecosystem dynamics under the varying human impacts, estimating of the risks of the irreversible ecosystem changes and of the possible catastrophic ecological consequences are in agreement with those principles. The principles of the sustainable development, the rational use of the natural resources, and of the ecosystem management underlying the project approach agree with the world-wide recognition of their importance for the national security systems and economical development.
The project is the further developing of our long-term investigations of human made dynamics of desert and forest ecosystems and population processes in communities of small mammals at the areas including natural foci of different infections. All members of the project have a great experience in such medico-biological researches and in elaboration of recommendations for nonspecific preventive measures for natural foci infections, and they are skilled experts in estimation of consequences of ecological and man-caused disasters.
In particular we have studied main regularities of ecosystems dynamics under disasters (Shilova, 1990; Shilova et al., 1991) and after removing of human made impacts (Neronov et al., 1997; Neronov, 1998; Tchabovsky, 1998; Tchabovsky, et al.1999; Shilova et al., 2000), - dynamics and structure of rodent populations under dramatic environmental changes in natural foci in different regions of the world (Suntsov, 1987; Shilova, 1984; Shilova, 1993; Shilova et al., 1994; Shilova, 1999; Sokolov, Shilova, Schipanov, 1994; Tchabovsky, et al., 1996); - functioning of foci in man-made landscapes (Shilova, 1972; Schipanov et al., 1984; Shchipanov, 1987), - consequences of ecological and man-caused disasters, military operations; approaches to reconstruction of violated landscapes (Shilova, 1993; 1999; Shatunovsky, Shilova, 1995; Archegov et al., 1993; Slotin, 1995; Schipanov, Savinetskaya, 1996; Schipanov et al., 1996; Sokolov, Shilova, 1996; Sokolov et al., 1997; Bocharov, Shadrin et al., 1996). Original techniques for data collection, estimation of ecosystem conditions, monitoring of small mammals population in forest and steppe zones have been elaborated (Shchipanov et al., 2000; Shchipanov., 2000; Isaev, Shilova, 2000; Shilova et al., 2000).
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