ABSTRACT
Objective To study the epidemiological significance of community-structural difference regarding both small mammal and flea communities on Rattus ftavipectus in Dehong and Baoshan areas,Yunnan province,during 1982 to 1996.Methods Methodologies as cluster analysis,communities dominated constitution and species diversity were used for data analysis.Results 75 490 small mammals of 27 species could be divided into three types:Ⅰ.Ruili habitat-communities dominated bv R.flavipectus (54.41%)and Suncus murinus(33.37%): Ⅱ.Longchuan and Yingiiang habitat-communities dominated by R.flavipectus(62.99%),S.murinus(23.25%)and Mus musculus(10.06%);Ⅲ.Baoshan habitat-community dominated by R.flavipectus(48.07%),S.murinus(19.56%)and Crocidura attenuats(14.37%).The captured 61 122 fleas of 11 species on R.flavipectus could be divided into three types: i.Ruili habitat-communities dominated by Xenopsylla cheopis(83.51%)and Lentistivslius ferinus(13.86%);ii.Longchuan and Yingjiang habitats X.cheopis(74.42%)and L.segnis(22.94%); iii.Baoshan habitat-communities dominated by L.segnis(70.62%)and X.cheopis(22.70%).There had been 1471 strains of Y.pestis isolated from the hosts of 7 species and vectors of 5 species in Dehong areas for the ten year period.36 strains of Y.pestis were isolated from host of one species and vectors of 2 species in Baoshan area for ten years.The constitution ratio of R.flavipectus and X.cheopis was higher in Dehong area with average as 58.70%and 78.97%respectively.However.the diversities of species among host and vector communities were low,with average as 1.010 and 0.625.On the contrary,the constitution ratios of R.flavipectus and X.cheopis were lower in Baoshan area.with an average as 48.07%and 22.70%respectively but the diversities of species among host and vector community were higher with the averages as 1.471 and 0.829 respectively.The main dominative flea species from 'group ii'to 'group iii'in the flea community had changed from X.cheopis to L.segnis.Conclusion The species diversity index of host and vector community was higher in Baoshan area,while the constitution ratio of main host and vector community was lower.This findings seemed to be the important factor of the decrease of plague prevalence in Baoshan area.
ABSTRACT
Understanding the transmission ecology of parasites involves the challenge of studying the complexity of life-cycles at multiple levels of biological organisation and at various space-time scales. We think that a single field of science alone cannot fully address this issue and that a way to understand such complexity is to connect various fields of science, to consider the whole transmission system, and to identify which are the variables reasonably accessible to measurement and the relevant scales at which they may provide information about transmission processes and indicate a higher risk of transmission⁄emergence. Based on ongoing studies carried out in Europe and in China, the aim of the present paper is to discuss this approach and to show how results obtained from mass-screening of human populations may be combined to those obtained from small mammal and landscape ecology studies and modelling to promote an understanding of <I>Echinococcus multilocularis</I> transmission and to determine how differences in the time-space scales at which human infection and small mammal population dynamic processes occur may complicate the analysis.