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.