| [serological study of nontriturated fleas following preliminary cultivation of the plague microbe]. | under experimental conditions there was shown a possibility of serological study of nontriturated fleas for the presence of past. pestis. hottinger's broth with gentian-violet ((0.0003%) sodium sulfite (0.03%) and a surfactant--o (see article)-7 (3%) served as the growing medium. after the nontriturated fleas were grown for 48 hours at 37 degrees c the capsular antigen was detected with the aid of the passive hemagglutination and antibody neutralization tests. detection of the capsular antigen i ... | 1975 | 123679 |
| [fleas of the eastern kyzyl kum and their epizootic significance]. | the fauna of fleas in the east kisil-kum includes 24 species. different physicogeographic regions of sands are characterized by different spectra and number of species of fleas. the greatest share in collections is composed by xenopsylla gerbilli caspica--the parasite of rhombomys opimus. in autumn the other parasite of this rodent, coptopsylla lamellifer, is a mass species. all the most significant and long changes in the number of these species are associated with changes in the density of the ... | 1991 | 1839698 |
| [blood groups of great gerbils (rhombomys opimus licht.) as an indicator of population resistance to infections]. | three genetic systems of blood groups of great gerbils were studied to reveal that different resistance patterns exist in rodents toward yersinia pestis and salmonella typhimurium. extrapolation of the results obtained on relations of co-members of parasite systems contributes to understanding of some points of immunobiological mechanisms of dynamics of expizootic procedures. a hypothesis is proposed claiming that isoantigenic blood structure of the host is responsible for formation of populatio ... | 1990 | 2344947 |
| long-term analysis of data on the isolation of yersinia pestis cultures from rodents during epizootological examinations of natural foci in muyun-kum and eastern kizil-kum. | results are presented of a long-term examination and evaluation of data on the microbiological procedures of isolating yersinia pestis cultures from wild mammals and their association animal plague pathogenesis as suggested by investigations in the muyun-kum autonomous plague focus and the eastern kizil-kum mesofocus. 1772 yersinia pestits cultures were isolated largely from rhombomys opimus as the principle host over 23 years. the authors determined the frequency of pathological alterations in ... | 1989 | 2533934 |
| [yersinia pestis l-forms in rodents and ectoparasites]. | y. pestis l-forms and bacterial forms persist in the body of great gerbils for 40 days. l-forms are poorly phagocytized and can persist in phagocytes for a long time. in guinea pigs immunized with vaccine ev, y. pestis antigen could be detected till day 160. an unstable l-form was isolated from ornithodoros mites 3 years after their experimental infection with y. pestis. bacterial forms persist in mites for 1-3 years. for 5 years y. pestis antigen is regularly detected in a high percentage of mi ... | 1989 | 2728699 |
| [antigenuria in plague-infected great gerbils]. | in the urine of plague-infected great gerbils yersinia pestis capsular antigen was detected by means of diagnostic preparations, both commercial and experimental (based on monoclonal antibodies). the antigen was detected in many urine samples taken from the animals over a prolonged period. the incidence and duration of antigenuria were found to be related to the survival time of great gerbils after infection and the level of antibodies in their blood. the number of animals with antigenuria marke ... | 1988 | 2966529 |
| [duration of the presence of plague and pseudotuberculosis bacteriophages from the organism of rhombomys opimus]. | | 1965 | 5894172 |
| [isolation of l-form of yersinia pestis from wild rodents in an epizootic focus]. | four y. pestis cultures with unbalanced growth and 15 y. pestis cultures in unstable l-forms were isolated from wild rodents rhombomys opimus in the vicinity of lake balkhash. morphologically they were mainly represented by granular, spheroplast-like and filiform elements. when stained with luminescent serum, they acquired specific fluorescence; in indirect hemagglutination they yielded positive result. electron microscopy revealed the presence of morphological elements characteristic of the pro ... | 1982 | 7180264 |
| [the effect of trace elements on the infectious process in plague in an experiment]. | the influence of mn, fe, co, ni, cu and zn on experimental yersinia pestis infection in three species of gerbils (rhombomys opimus, meriones meridianus, m. tamariscinus) under conditions, imitating natural biogeochemical anomalies, was studied. the addition of co and ni to the fodder given to the animals for the period of 2-4 weeks prior to infection aggravated the course of infection. in similar experiments cu, fe and mn aggravated or, on the contrary, inhibited the development of infection, de ... | 2000 | 10876891 |
| [on the nature of bacterial strains isolated from rhombomys opimus in the tedzhen-murghab interfluvial area (turkmen ssr)]. | | 1965 | 14270023 |
| predictive thresholds for plague in kazakhstan. | in kazakhstan and elsewhere in central asia, the bacterium yersinia pestis circulates in natural populations of gerbils, which are the source of human cases of bubonic plague. our analysis of field data collected between 1955 and 1996 shows that plague invades, fades out, and reinvades in response to fluctuations in the abundance of its main reservoir host, the great gerbil (rhombomys opimus). this is a rare empirical example of the two types of abundance thresholds for infectious disease-invasi ... | 2004 | 15118163 |
| epizootiologic parameters for plague in kazakhstan. | reliable estimates are lacking of key epizootiologic parameters for plague caused by yersinia pestis infection in its natural reservoirs. we report results of a 3-year longitudinal study of plague dynamics in populations of a maintenance host, the great gerbil (rhombomys opimus), in 2 populations in kazakhstan. serologic results suggest a mid-summer peak in the abundance of infectious hosts and possible transmission from the reservoir to humans. decrease in antibody titer to an undetectable leve ... | 2006 | 16494753 |
| plague dynamics are driven by climate variation. | the bacterium yersinia pestis causes bubonic plague. in central asia, where human plague is still reported regularly, the bacterium is common in natural populations of great gerbils. by using field data from 1949-1995 and previously undescribed statistical techniques, we show that y. pestis prevalence in gerbils increases with warmer springs and wetter summers: a 1 degrees c increase in spring is predicted to lead to a >50% increase in prevalence. climatic conditions favoring plague apparently e ... | 2006 | 16924109 |
| 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 it ... | 2007 | 17156497 |
| statistical analysis of the dynamics of antibody loss to a disease-causing agent: plague in natural populations of great gerbils as an example. | we propose a new stochastic framework for analysing the dynamics of the immunity response of wildlife hosts against a disease-causing agent. our study is motivated by the need to analyse the monitoring time-series data covering the period from 1975 to 1995 on bacteriological and serological tests-samples from great gerbils being the main host of yersinia pestis in kazakhstan. based on a four-state continuous-time markov chain, we derive a generalized nonlinear mixed-effect model for analysing th ... | 2007 | 17254979 |
| climatically driven synchrony of gerbil populations allows large-scale plague outbreaks. | in central asia, the great gerbil (rhombomys opimus) is the main host for the bacterium yersinia pestis, the cause of bubonic plague. in order to prevent plague outbreaks, monitoring of the great gerbil has been carried out in kazakhstan since the late 1940s. we use the resulting data to demonstrate that climate forcing synchronizes the dynamics of gerbils over large geographical areas. as it is known that gerbil densities need to exceed a threshold level for plague to persist, synchrony in gerb ... | 2007 | 17550884 |
| the abundance threshold for plague as a critical percolation phenomenon. | percolation theory is most commonly associated with the slow flow of liquid through a porous medium, with applications to the physical sciences. epidemiological applications have been anticipated for disease systems where the host is a plant or volume of soil, and hence is fixed in space. however, no natural examples have been reported. the central question of interest in percolation theory, the possibility of an infinite connected cluster, corresponds in infectious disease to a positive probabi ... | 2008 | 18668107 |
| [study on the situation of plague in junggar basin of china]. | to understand the distribution, fauna, population structure of host animals and their parasitic fleas as well as popular dynamic of animal plague of natural plague foci in junggar basin. | 2008 | 18686853 |
| modeling the epidemiological history of plague in central asia: palaeoclimatic forcing on a disease system over the past millennium. | human cases of plague (yersinia pestis) infection originate, ultimately, in the bacterium's wildlife host populations. the epidemiological dynamics of the wildlife reservoir therefore determine the abundance, distribution and evolution of the pathogen, which in turn shape the frequency, distribution and virulence of human cases. earlier studies have shown clear evidence of climatic forcing on contemporary plague abundance in rodents and humans. | 2010 | 20799946 |
| dynamics of the plague-wildlife-human system in central asia are controlled by two epidemiological thresholds. | plague (caused by the bacterium yersinia pestis) is a zoonotic reemerging infectious disease with reservoirs in rodent populations worldwide. using one-half of a century of unique data (1949-1995) from kazakhstan on plague dynamics, including data on the main rodent host reservoir (great gerbil), main vector (flea), human cases, and external (climate) conditions, we analyze the full ecoepidemiological (bubonic) plague system. we show that two epidemiological threshold quantities play key roles: ... | 2011 | 21856946 |
| [experimental observation on the histopathological and ultrastructural pathology of great gerbils (rhombomys opimus) in the junggar basin by subcutaneous injecting of yersinia pestis]. | objective: to understand the histopathological and ultrastructural pathology changes of great gerbils in the junggar basin to yersinia pestis infection. methods: forty captured great gerbils from the junggar basin that tested negative for anti-f1 antibodies were infected. the y. pestis strain 2504, isolated from a live great gerbil in the natural plague foci of the junggar basin in 2005 with a median lethal dose (ld(50)) of <10 cfu/ml, was used in this study. forty great gerbils were divided int ... | 2017 | 28219158 |
| spatial distribution patterns of plague hosts: point pattern analysis of the burrows of great gerbils in kazakhstan. | the spatial structure of a population can strongly influence the dynamics of infectious diseases, yet rarely is the underlying structure quantified. a case in point is plague, an infectious zoonotic disease caused by the bacterium yersinia pestis. plague dynamics within the central asian desert plague focus have been extensively modelled in recent years, but always with strong uniformity assumptions about the distribution of its primary reservoir host, the great gerbil (rhombomys opimus). yet, w ... | 2015 | 26877580 |
| the perfect burrow, but for what? identifying local habitat conditions promoting the presence of the host and vector species in the kazakh plague system. | the wildlife plague system in the pre-balkhash desert of kazakhstan has been a subject of study for many years. much progress has been made in generating a method of predicting outbreaks of the disease (infection by the gram negative bacterium yersinia pestis) but existing methods are not yet accurate enough to inform public health planning. the present study aimed to identify characteristics of individual mammalian host (rhombomys opimus) burrows related to and potentially predictive of the pre ... | 2015 | 26325073 |
| transmission efficiency of the plague pathogen (y. pestis) by the flea, xenopsylla skrjabini, to mice and great gerbils. | plague, a zoonotic disease caused by yersinia pestis, is characterized by its ability to persist in the plague natural foci. junggar basin plague focus was recently identified in china, with rhombomys opimus (great gerbils) and xenopsylla skrjabini as the main reservoir and vector for plague. no transmission efficiency data of x. skrjabini for y. pestis is available till now. | 2015 | 25928441 |
| plague epizootic cycles in central asia. | infection thresholds, widely used in disease epidemiology, may operate on host abundance and, if present, on vector abundance. for wildlife populations, host and vector abundances often vary greatly across years and consequently the threshold may be crossed regularly, both up- and downward. moreover, vector and host abundances may be interdependent, which may affect the infection dynamics. theory predicts that if the relevant abundance, or combination of abundances, is above the threshold, then ... | 2014 | 24966205 |
| 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 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-desert landscape. the study area consists o ... | 2013 | 24817838 |
| potential corridors and barriers for plague spread in central asia. | plague (yersinia pestis infection) is a vector-borne disease which caused millions of human deaths in the middle ages. the hosts of plague are mostly rodents, and the disease is spread by the fleas that feed on them. currently, the disease still circulates amongst sylvatic rodent populations all over the world, including great gerbil (rhombomys opimus) populations in central asia. great gerbils are social desert rodents that live in family groups in burrows, which are visible on satellite images ... | 2013 | 24171709 |
| local persistence and extinction of plague in a metapopulation of great gerbil burrows, kazakhstan. | speculation on how the bacterium yersinia pestis re-emerges after years of absence in the prebalkhash region in kazakhstan has been ongoing for half a century, but the mechanism is still unclear. one of the theories is that plague persists in its reservoir host (the great gerbil) in so-called hotspots, i.e. small regions in which the conditions remain favourable for plague to persist during times where the conditions in the prebalkhash region as a whole have become unfavourable for plague persis ... | 2012 | 23351373 |
| dynamics of yersinia pestis and its antibody response in great gerbils (rhombomys opimus) by subcutaneous infection. | rhombomys opimus (great gerbil) is a reservoir of yersinia pestis in the natural plague foci of central asia. great gerbils are highly resistant to y. pestis infection. the coevolution of great gerbils and y. pestis is believed to play an important role in the plague epidemics in central asia plague foci. however, the dynamics of y. pestis infection and the corresponding antibody response in great gerbils have not been evaluated. in this report, animal experiments were employed to investigate th ... | 2012 | 23071647 |
| draft genome sequence of yersinia pestis strain 2501, an isolate from the great gerbil plague focus in xinjiang, china. | we deciphered the genome of yersinia pestis strain 2501, isolated from the junggar basin, a newly discovered great gerbil plague focus in xinjiang, china. the total length of assembly was 4,597,322 bp, and 4,265 coding sequences were predicted within the genome. it is the first y. pestis genome from this plague focus. | 2012 | 22965078 |
| a curve of thresholds governs plague epizootics in central asia. | a core concept of infectious disease epidemiology is the abundance threshold, below which an infection is unable to invade or persist. there have been contrasting theoretical predictions regarding the nature of this threshold for vector-borne diseases, but for infections with an invertebrate vector, it is common to assume a threshold defined by the ratio of vector and host abundances. here, we show in contrast, both from field data and model simulations, that for plague (yersinia pestis) in kaza ... | 2012 | 22449078 |
| [dynamics of f1 antibody responses to yersinia pestis infection in rhombomys opimus]. | objective: to observe the dynamics of antibody response in great gerbils infected with yersinia pestis in experiment. method: a total of 211 great gerbils were captured in the southern margin of plague natural focus of junggar basin of the xinjiang uygur autonomous region in 2011. among them, there were 167 great gerbils without infection of y. pestis and 44 great gerbils infected by y.pestis. y.pestis no. 2504 was employed for this experimental strain, which was strong toxic strain with negativ ... | 2017 | 28395471 |