[changes in activity of natural foci of plague in tuva region]. 200314564843
[relationships of parasitic triad co-members in a tuva natural plague focus: environmental and physiological aspects (experimental studies)].long-term experimental studies of the environmental and physiological aspects of relationships of parasitic triad co-members, performed in a tuva natural plague, by using citellophilus tesquorum altaicus fleas, their natural feeder--a long-tailed siberian souslik (citellus undulatus), and the yersinia pestis strain i-3226 that is typical of the focus were analyzed. a complex of biotic (the environmental features of a causative agent, avector, and a carrier) and abiotic (air temperature and moist ...200415689135
[role of fleas, the principal and secondary plague vectors, in the circulation of the causative agent in siberian natural foci].the paper reviews data on the role of fleas as the principal and secondary vectors of infection in the siberian natural foci of plague. the role of citellophilus tesquorum as the principal plague vectors in the transbaikalian and tuvinian natural foci is shown to be determined by their ecological characteristics (the degree of specificity to the main host, numbers, and natural infection) to a greater extent and by the rate of block formation to a lesser extent. the significance of principal and ...200818822506
[the formation of proventriculus block, alimentary activity and mortality of flea amphipsylla primaris primaris infected with yersinia pestis].the results of experiments held in 1982-1983 in tuva plague natural focus with flea amphipsylla primaris primaris (jordan et rothschild, 1915) from natural populations, whish were inflected and fed on specific host--flat-headed vole (alticola strelzovi), are analyzed. the initial infectivity of the insects in autumn was higher than in spring: 90 and 50 % respectively. accumulation of the agent in aggregated form in the organism of a. p. primaris, estimated by the quantity of fleas with <<lumps>> ...200616913294
[relationship of the flea citellophilus tesquorum altaicus (siphonaptera: ceratophyllidae) with the plague agent].some aspects of relationships of the flea citellophilus tesquorum altaicus and bacterium yersinia pestis of two strains isolated from different parts of the tuva natural plague focus were studied. peculiarities of elimination and blood meal activity of fleas infected with two strains of the plague agent were not revealed. differences in mortality and alimentary activity are considerably determined by the sex of insects. the ability of examined strains to form a proventriculus block was not ident ...200415174390
[seasonal dynamics of infecting ability of the flea citellophilus tesquorum altaicus in the tuva natural focus of the plague].the infecting ability of the fleas citellophilus tesquorum altaicus loff, 1936, the main plague vectors in the tuva natural focus, was experimentally studied in different periods of the epizootic season. seasonal dynamics in the efficiency of infecting the long-tailed siberian souslik with the plague causative agent through flea bites was noticed. seasonal differences in infectivity of the "blocked" flea bites are revealed. an increase of infected experimental animals with a generalization of in ...200415069878
[differences between two populations of citellophilus tesquorum altaicus from the tuva natural focus of plague].citellophilus tesquorum altaicus fleas from two natural (karginsky and barlyksky) populations have been studied. there are differences between the fleas of these populations in susceptibility to plague microbe. the adaptability and abundance of the causative organism in the body are higher in the fleas of the barlyksky population. the sizes of the head are significantly higher in the females of the karginsky population. there are no differences in this index between males. according to all 5 stu ...200415042747
[an experimental study of the possibility for the preservation of the causative agent of plague in the nest substrate of the long-tailed suslik].how long yersinia pestis can preserve in the nest substrate of spermophililus undulatus and whether it can infect the animals contacting with the substrate infected with flea feces and carcasses were studied in a tuva natural focus. the infected material was kept in special niches of a bunkering laboratory, which imitated a souslik nest. biological, serological, and bacteriological studies were conducted after different storage periods. the experiment used 25 sousliks, 56 albino mice, and 3256 f ...19979445996
[the duration of the persistence of the plaque microbe in the body of the flea citellophilus tesquorum altaicus].experiments have established that the plague bacillus persists long in the flea c. tesquorum altaicus in the tuva natural foci. experimentally, 64.2 to 77.3% of the fleas inoculated in autumn survived winter. more than one-half preserved the plague bacillus. from 0.7 to 19.4% of the inoculated fleas survived from one summer to another. the plague persisted in 30% of the insects. individual c. tesquorum altaicus females survived two winters, preserving the bacillus for 21.5-22.0 months. the fact ...19968700014
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 ...19892533934
[the epizootiological significance of flea accumulation in aggregations of the female long-tailed suslik in the tuva plague focus].the formation of aggregations of related females is a peculiarity of the intrapopulational organization of long-tailed suslik that results in the accumulation of citellophilus tesquorum, the main vector and keeper of the plague microbe in the tuva plague nidus. the plague agent is adapted to the existence on the territory occupied by aggregations of females that manifests itself in the delay of the beginning and prolixity of block-formation periods in fleas. the transfer of the agent from one pl ...19902216531
[results of the vntr-analysis in a locus (5'-naaa-3')n of strains yersinia pestis from the active natural foci of plague of siberia].the method of the vntr-analysis in a locus (5'-naaa-3')n was studied using samples of the dna of 73 strains y. pestis ssp. altaica, isolated in gorno-altaisk and 65 strains y. pestis ssp. pestis, allocated in tuva natural foci of plague. it was demonstrated that strains from the gorno-altaisk population of plague microbes possessed genomic polymorphism in the locus given a marker that is reflected in variability of the size of an amplicon from 250 up to 275 bp, correlating with places of isolati ...200919705777
[reservation forms of plague infectious agent in tuva natural focus].data characterizing the reservation forms of plague infectious agent in tuva natural focus are presented in the review. yersinia pestis was shown to persist most of the year in citellophilus tesquorum altaicus imago --the main carrier, getting into the animal organism only for a short time. an increased ability to aggregate in autumn and accumulate in clumps of c. tesquorum altaicus females that are more adapted to survive the cold season compared with males promote the persistence of the microo ...201223163049
[the survival of the causative agent of plaque in the long-tailed suslik from a tuva natural focus in wintertime].the survival of the causative agent of plague in the long-tailed souslik in the tuva natural focus in winter was experimentally studied. they were made in a special bunker laboratory just in the focus. the experimental conditions were close to the hygrothermal parameters of a long-tailed souslik's burrow. inoculation and placement of the animals and fleas into the bunker were accomplished in the september to early october. the rodents and ectoparasites were examined after their hibernation in th ...199910414051
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