多聚酶链反应在阿米巴病流行病学研究中的应用

用两对引物扩增（ＰＣＲ）溶组织内阿米巴带囊者粪便中的ＤＮＡ，以鉴别感染虫株的致病性，致病和非致病性ＰＣＲ均为阳性者１人（３．１％），仅一项阳性者分别为６人（１８．８％）和２５人（７８．１％）。７例致病性ＰＣＲ阳性者中，６人有腹泻症状（ＯＲ＝３１．５）。各种对照标本均呈ＰＣＲ阴性反应。以ＰＣＲ法对一小样本人群进行阿米巴病调查，致病和非致病虫株的感染率均为１０％。结果表明，在阿米巴病流行病学调查中，可

Application of the Polymerase Chain Reaction to the Epidemiological Study of Amoebiasis

The polymerase chain reaction(PCR)has been used in studying the pathogenicity of Entamoe-ba histolytica in a rural commtinity in Shandong province. Formalin-fixed stool samples were used for extraction of DNA.The PCR amplifications were performed using two sets of primer that dis-criminate between pathogenic and nonpathogenic E.histolytica. All of the 32 cases of cyst carrier diagnosed microscopically were identified as positive. Three groups were defined through PCR analysis:6 cases(18.8%)were positive for pathogenic but negative for nonpathogenic,25 cases (78.1%)were negative for pathogenic but positive for nonpathogenic,and only one case(3.1%)was positive for both pathogenic and nonpathogenic. The cases found to be pathogenic by PCR were also closely correlated with their clinical manifestations(diarrhea)(OR=31.5,P<0.005).All of the control cases showed negative reaction to PCR.PCR has also been used to study the epi-demiology of amoebiasis in a small population group with 40 persons in the same province. Both positive rates by PCR on pathogenic and nonpathogenic were 10%. The results showed that this new technique can be applied in the field for the epidemiological studies of pathogenic and non-pathogenic E. histolytica.