[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
[the quantity of blood ingested by various species of fleas in an experiment].data are given on the blood amount engorged by the fleas xenopsylla conformis, x. cheopis, leptopsylla segnis, nosopsyllus laeviceps, n. consimilis, ctenophthalmus golovi, neopsylla setosa, citellophilus tesquorum and coptopsylla lamellifer. the average weight of blood portion in females of different species engorged for the first time ranged from 0.05 mg (x. conformis) to 0.72 mg (c. lamellifer). females of most species, which had multiple blood meals, engorge more blood. males engorge less blo ...19883205580
[the variability of yersinia pestis in the body of the flea].changes in the morphology and ultrastructure of y.pestis cells at different periods of their stay in the body of fleas (citellophilus tesquorum altaicus) have been studied. the study, carried out by means of optical and electron microscopy, as well as with the use of a culture medium for the isolation of l-forms, has revealed that in the body of fleas y.pestis cells undergo the effect of processes leading to their l-transformation. as the result of l-transformation, the infective agent may take ...19947941859
[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
[asymmetry of the chaetae in fleas (citellophilus tesquorum) as a possible marker of their capacity for blocking].the fluctuating asymmetry was studied according to two bilateral numeric features of chaetaxy in groups of female citellophilus tesquorum fleas. one group included insects with the recorded gizzard block during infection with the virulent plague agent strain. the fleas with the block were characterized by considerably higher levels of fluctuating asymmetry as compared with those without fleas.19979182193
[influence of a temperature factor on the vector capacity of the flea citellophilus tesquorum altaicus].the impact of temperatures (2-3 to 23-25 degrees c) of flea keeping on their vector capacity was studied in the experiment. in hibernated fleas, the relationship of their vector capacity to the temperature of their keeping, estimated by the level of plague block in species and by the case rates of animals was insignificant, i.e. there is a trend for these indices to increase with elevated temperatures. in the fleas of current years breeding, the rate of block significantly increased with a rise ...200314564839
[detection of plague microbe in the fleas by polymerase chain reaction by using magnetic immunosorbents].the polymerase chain reaction (pcr) with and without pre-treatment of the samples of the fleas citellophilus tesquorum with magnoimmunosorbents was used to detect the plague microbe in the samples containing 142, 168, 193 or more bacterial cells. pcr analysis reduced the time of tests of ectoparasites for plague to 6 hours. the use of a combination of pcr and magnoimmunosorbent simplified the most time-consuming and longest stage of isolation of plague microbial dna from the suspensions of the f ...200415042746
[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
[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
[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 features of the time course of changes in the aggregated state of the causative agent of plague in the organism of citellophilus tesquorum altaicus (siphonaptera)].the data of experiments made in a tuva natural plague focus with the main vector of the flea c. lesquorum altaicus during different seasons are analyzed. ectoparasites were infected with the plague microbial strain typical for the focus and fed on natural nourishment, such as long-tailed sousliks. an analysis indicated that estimation of the parameter "the proportion of infected insects containing the causative agent at the aggregated state" is of greater informative value than is the recording ...200415193040
[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
[conservation of yersinia pestis in winter by citellophilus tesquorum altaicus females and males].intersexual differences have been established in citellophilus tesquorum altaicus ioff (1936) from a tuva natural focus in the accumulation of yersinia pestis in fleas in autumn and its conservation during winter. the ectoparasites were infected and fed on the natural feeder - long-tailed siberian souslik (citellus undulates). small wild animals and insects were infected with the strain yersinia pestis 1-3226 typical of the focus. in winter fleas survived without the feeder under artificially cr ...200718277419
[relations of the causative agents of plague and listeriosis during their simultaneous stay in the flea citellophilus tesquorum at different environmental temperatures].experiments were carried out to determine the persistence of a plague microbe with varying praline labeling (isolated in the central caucasian mountain focus of plague in the fleas citellophilus tesquorum of a mountain subspecies) in the contamination of the mixed culture of the plague microbe and listeria. inoculation of fleas with a suspension of a plague microbe and listeriae demonstrates the manifest signs of antagonism between both species of microorganisms. this is evidenced by the reducti ...200818368716
[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
[relationships of the plague pathogen and vector from different parasitic systems].the specific features of interaction of the strains of the plague microbe of the main subspecies, which circulate in the area of natural foci of mongolia and china, with citellophilus tesquorum sungaris fleas, the major vector of the plague pathogen in a transbaikalian natural focus, as well as with xenopsylla cheopis ones, the classical vector, were revealed. experiments used virulent yersinia pestis strains, such as i-3230 isolated from c.tesquorum in mongolia in 1998 and 2155 isolated from hu ...201323805481
[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
[trend in the emergence of flea imagoes from cocoons in the nests of a mountain gopher (spermophilus musicus) in the central caucasian highland natural focus of plague].the results of observations of a trend in the emergence of flea imagoes from cocoons in the nests of mountain gopher (spermophilus musicus) (elbrus region) confirm that the dominant species: citellophilus tesquorum elbrusensis and ctenophthalmus golovi golovi have two generations. emergence of first-generation imagoes from cocoons is recorded in july-august in the nests where the grophers constantly inhabit in may-june. these are brood-rearing and other summer nests and, to a lesser degree, form ...201323437722
[host influence on the frequency of block formation in males and females of citellophilus tesquorum altaicus ioff, 1936 (siphonaptera: ceratophyllidae) and transmission the plague pathogen by these fleas].data obtained during feeding of citellophilus tesquorum aitaicus ioff, 1936 infested females and males (siphonaptera: ceratophyllidae), the main vectors of plague in tuva natural plague locus, on the natural host and laboratory animal was analyzed. it was found that sexual differences in fleas depended on the type of the host. females fed more actively on the longtailed ground citellus undulatus than on white mouse. alimentary activity of males on these animals was similar. higher mortality of f ...201222834346
[the epizootiological role of the population organization of the stock of fleas on the long-tailed suslik in a natural focus of plague in tuva].spatial location of epizootic events in the tuva plague focus is determined at a considerable degree by the population structure of the flea citellophilus tesquorum--the main plague microbe vector. within the enzootic territory occupied by five populations of the long-tailed ground squirrel (citellus undulatus) there are six populations of c. tesquorum. each population of fleas has a corresponding autonomic plague focus. various conditions for the microbe life activity in these populations are r ...201010771772
[the duration of preservation of plague pathogen strains with a different plasmid kit from a central caucasian high-altitude natural focus in the organism of citellophilus tesquorum fleas and the possibility of their transmission to laboratory animals].two plasmid variants of the main subspecies of the plague microbe circulate in a central caucasian high-altitude natural focus of plague. the strains of one plasmid variant fully correspond to the main subspecies of the plague pathogen in their characteristics. those of the other are auxotrophic for proline, weakly virulent to one or both species of laboratory animals. the mountain subspecies of citellophilus tesquorum fleas excretes the greatest quantity of plague microbe strains so the investi ...201323805482
[block formation in citellophilus tesquorum altaicus ioff, 1936, fleas in relation to the sex of an insect].males and females of c. tesquorum altaicus, the main vector of plague in its natural focus, were experimentally studied in different seasons (spring, summer) for their capacity of block formation. the experiments used 2 groups of fleas: the insects that have been infected in last autumn and hibernated and <young> insects, a that year's breeding. the investigations demonstrated that the hibernated fleas had insignificant differences (p>0.05) in the rates of block formation by sex in spring and ea ...201016366014
[the determination of toxicity of four insecticides on ground squirrel flea].this paper reports the results of toxicological effect of four insecticides on citellophilus tesquorum sungaris. the toxicity of deltamethrin was the strongest in four insecticides, ddvp & ddt were stronger than 1-(3,4-dichlorophenyl)-2,2,2-trichloroethyl acetate. for the ld50 of four insecticides on suckling blood female flea of two-day-age, were 1.17 x 10(-6) micrograms per flea 1.20 x 10(-3) micrograms per flea 1.25 x 10(-3) micrograms per flea & 3.46 per flea respectively. the data showed th ...19892776194
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