Genotype ; Humans ; Yersinia pestis

Plague cases were reported at Eawy commune, Eah'leo district of Dak lak province in March 1997. Y. pestis was isolated from 1.42% of rat samples. 2.89% of rat serum samples and 20% of human serum samples contained anti-plague antibody. The reproductive season of X.cheopis has been coincided with plague season, peaking in the dry season. The plague and vector development seasons in Eawy have all typical characteristics of plague in the High-Plateau region
Plague ; Yersinia pestis ; Rats ; Humans

Pla sequence composes of 480 nucleodides of pPCP1 plasmide originated from Yersinia pestis isolated from Viet Nam and collected by the technique of PCR of chemical line into TA vector and demonstrated in turn. PCR reaction gave specific result from 3 diversified sources for mould: total extracted ADN, ADN extracted from plasmide isolated from bacterium complete cell. A fast and accurate method of diagnosis was created basing on this operation. By BLAST programme for accessing Gene Bank, the pla-gene sequence of Yersinia pestis in Viet Nam is analogue to other strains worldwide
Yersinia pestis ; Genetic Markers ; Biochemistry

OBJECTIVETo explore the spatial and temporal distributions of animal plague in Junggar Basin natural plague focus.

METHODSData regarding plague antibody (F1) in serum of Great Gerbil (Rhombomys opimus, R. opimus) which were collected from 2005 to 2012 in Junggar Basin and analyzed. The changing rates on the positivity of F1 that appeared spatially and temporally were also analyzed.

RESULTSA total of 4 825 R. opimus serum samples were collected in 13 administrative regions in Junggar Basin.

RESULTSshowed that plague R. opimus existed in two areas-Gurbantonggut desert in the eastern-center and the clay desert of western Junggar Basin. However, in these two areas, the intensity of animal plague prevalence was different. In the former region where Yesinia pestis positive serum was detected from R. opimus, the detected rate of R. opimus was 8.39%. However, in the latter areas, the average positive rate was 1.56%. The changing trends of R. opimus plague prevalence were also varied annually. In the western Junggar Basin, the trend showed a slowly downward profile. The serum positive rate of R. opimus for Yesinia pestis decreased, from 7.59% in 2005 to 0.61% in 2008, and appeared as a resting state that none of the positive sample could be found since then. However, in the eastern-center Junggar Basin area-also named as Gurbantonggut desert which had been divided into 3 segments(western, central and eastern, according to related geographical characteristics), the changing trends of animal plague seemed quite complex. In the western segment, the animal plague had two epidemic peaks-in 2006 and 2010, with the interval of 4 years, with the higher peak of all the three geographic segments as 45.65% in 2010 and the positive serum of R. opimus for plague could be detected each year from 2006 to 2012. However, there were 3 epidemic peaks in the same period in the central and eastern segments. In the central segment, the peaks appeared in 2006, 2009 and 2011, with the intervals as 2.5 years and the average positive rate 8.92% was seen the lowest in Gurbantonggut desert. In the eastern segment, the first 2 peaks appeared the same season as in the central segment, but the third peak appeared in 2012, with the peak interval as 3 years. The positive rate of R. opimus for plague was also different in seasons, with the positive rate higher in autumn than in spring. These findings showed that the animal plague could be continuously prevalent from spring to autumn in the natural foci of plague in the Junggar Basin.

CONCLUSIONBoth geographical and temporal fluctuations of animal plague existed in the natural foci of Junggar Basin which was also named as geographical heterogeneity. Consequently, animal plague could be divided into two areas-the clay plains desert in the western and the Gurbantonggut desert in the eastern-center Junggar Basin.

OBJECTIVETo analyze the plasmid features and geographical distribution characteristics of Yersinia pestis of different plague foci in China.

METHODSA total of 2 213 Yersinia pestis strains were colected from 11 Chinese plague foci separated during 1943 to 2012, and plasmid DNA according to alkali cracking method, and measured the relative molecular mass (Mr) of plasmid DNA based on the standard plasmid contrast method, then analyzed the plasmid profiles by agar gel electrophoresis.

RESULTSA total of 2 213 strains had 16 kinds of plasmids with different Mr, including 4×10(6), 6×10(6), 7×10(6), 13×10(6), 16×10(6), 20×10(6), 22×10(6), 23×10(6), 27×10(6), 30×10(6), 36×10(6), 45×10(6), 52×10(6), 65×10(6), 72×10(6) and 90×10(6). Plasmid were classified into 26 kinds of plasmid profiles. A total of 2 213 Yersinia pestis strains contained 4 large plasmids, 52×10(6), 65×10(6), 72×10(6) and 90×10(6), whose ratio was 22.10% (589/2 213), 75.60% (1 672/2 213), 0.17% (4/2 213), 2.12% (47/2 213), respectively. Among which, strains with plasmid 52×10(6), 65×10(6), 90×10(6) distributed in Qinghai-Tibet plateau Himalayan Marmot natural plague foci, strains with 72×10(6) plasmid only distributed in Inner Mongolia Meriones unguiculatus natural plague foci and Junggar Basin R. opimus natural plague foci, and 65×10(6) plasmid distributed in all the other foci.

CONCLUSIONStrains in Chinese 11 plague foci contained 4 kinds of large plasmid, the Mr respectively were 52×10(6), 65×10(6), 72×10(6), 90×10(6), which were classified into 26 kinds of plasmid profiles with other plasmid. These plasmid profiles distributed in relatively independent epidemic focus.

OBJECTIVETo study the distribution of genomovars and microevolution of Yersinia pestis in the Qinghai-Tibet Plateau.

METHODSPrimer pairs targeting the twenty-two different regions(DFRs) were designed for detecting the presence or deletion of each DFR in 297 strains isolated from the Qinghai-Tibet Plateau.

RESULTS9 genomovars, i. e. Genomovar 1, 5, 6, 7, 8, 10, 11, new type and Ype-ancestor were identified in the Marmota himalayana plague focus of the Qinghai-Tibet Plateau. Among these genomovars, genomovar 5,8 and 10 were dominant types. The total rate of the three genomovars was 80.6% (204/253) and the genomovars in different regions were different. All of 44 strains of Y. pestis in the Microtus fuscus plague focus of the Qinghai-Tibet Plateau belonged to genomovar 14.

CONCLUSIONThe distribution of genomovars of Y. pestis in the Qinghai-Tibet plateau had remarkable characteristics geographically. Based on the distribution of genomovars of Y. pestis, the routes of transmission and microevolution of Y. pestis were proposed.

Bacterial Typing Techniques ; Genotype ; Minisatellite Repeats ; Plague ; Yersinia pestis ; genetics

China ; Genome, Bacterial ; Phenotype ; Plague ; microbiology ; Yersinia pestis ; classification ; genetics

Animals ; China ; Genotype ; Plague ; genetics ; microbiology ; Yersinia pestis ; genetics

OBJECTIVETo type Yersinia (Y.) pestis isolates under different regions (DFR) and to observe their geographical distributions in China.

METHODS23 DFRs primers and PMT1 (plasmid) primer were used to verify the DFR genomovars of Y. pestiss strains from 11 plague foci in China. A total of 3 044 Y. pestis isolates were involved for analysis on DFR profiles with the characteristics of geographical distribution.

RESULTS52 genomovars were verified in 3 044 Y. pestis strains in China in which 19 genomovars as major and 33 genomovars as minor genomovar. 21 new genomovars, namely genomovar 32 to genomovar 52 were described on the basis of 31 genomovars previously confirmed. Three new genomovars belonged to new major genomovars, namely Himalayan marmot natural plague foci of the Qinghai-Tibet plateau newly added genomovar 32 and genomovar 44 as major genomovars. Mongolian gerbil natural plague foci of Inner Mongolia plateau were newly added genomovar 50 as one of the major genomovars.

CONCLUSIONAmong 21 new genomovars, 3 were major genomovars, with Chinese Y. pestis DFR as the major genomovars which had obvious distribution characteristics.