Relationship between endemic water exposure and prevalence of schistosomiasis in mountainous type

  Objective   To study dos-eresponse relationship forendemic waterexposure and prevalence of schistosomiasis of mountain type, in order to evaluate the advantages and disadvantages and applicability of the 3 indexes of endemic water exposure.

  Methods   One thousand and thirty three residents of the target population who were living around Qiong Sea were selected at random in November 2001.Three slices of Kato-Katz and 3 times Hatching for 3 stool samples to each residence were used to diagnosis schistosomiasis infection.The frequency of endemic waterex posure(frequency), the average time of endemic waterexposure(Index A)and the average density of endemic waterexposure(Index B)during April to October 2001 of the target population were studied by review questionnaire.

  Results   The dos-eresponse relationship was existed among three endemic waterexposure and schistosomiasis prevalence.In formerly study, the typical dose-response relationship was existed (χ²=17.76, P < 0.01)between frequency and prevalence in the natural village with schistosomiasis prevalence > 10%;theidentical dose-response relationship was existed(χ²=11.08, P < 0.01)between Index A and prevalence in the natural village with schistosomiasis prevalence < 10%.The dose-response relationship was not clear when the relation among indexes of endemic waterexposure and schistosomiasis prevalence was fluctuation under other condition.

  Conclusion   In the mountainous epidemic type of schistosomiasis, the frequency can be used for the endemic water exposure evaluation of the population with higher prevalence, index A can be used for the endemic water exposure evaluation of the population with lower prevalence.