Epidemiological investigation results of plague in Shanxi province

Objective To analyze the data collected from surveillance sites in Shanxi province in epidemiological investigations during 2004 - 2008 and understand the influence of such factors as rat density and vectorial quantities on plague epidemic intensity, thus provide some scientific basis for plague control and prevention. Methods To collect the data of surveillance during 2004 - 2008 in the 12 counties of plague surveillance by retrospective method. Sort and analyze the collected data according to the requirement of operational scheme for plague surveillance-calculate the rat density of spermophilus dauricus, meriones meridianus and the small rodents, and the flea index and the flea infection ratio of body flea, burrow track, cave. The results of serological tests were analyzed at the same time. Results As showed in the results, the mean density of spermophilus dauricus was 1.12 merely in each hectare, and that of meriones meridianus and small rodents were 7.42%(2130/28 700) and 8.03%(3886/48 400), respectively. The flea infection rate of spermophilus dauricus and meriones meridianas were 25.78% ( 1933/7497 ) and 44.19% (2028/4598), respectively;the flea index of spermophilus dauricus and meriones meridianus were 0.59 and 1.84, respectively. The number of nests excavated with flea for spermophilus dauricus was 70, and the numbers of nests and flea were 362 and 333, respectively. The flea infection rate was 19.34 % (70/362), and the flea index was 0.92. The number of nests excavated with flea for meriones meridianus was 34, and the numbers of nests and flea were 177 and 124, respectively. The flea infection rate was 19.21%(34/177), and the flea index was 0.70. The number of caves explored for spermophilus dauricus was 7171,and the number of burrows with flea was 62, so the flea infection rate was 0.86%(62/7171 ), and the flea index was 0.01. Conclusions With a relatively high density and large quantity and considering the epidemic features of animal plague in periphery provinces in recent years, plague may still happen and spread in Shanxi province diespite the negative results of all those serological tests, by means of importing from other provinces. Key words: Plague; Rat density; Flea index; Flea infection rate ; Epidemiology