中缅边境疟疾主动病例侦查范围与人群带虫者检测结果

Screening Radius of Active Case Detection and the Malaria Parasite Rate of Carriers in China-Myanmar Border

目的 探索我国中缅边境地区疟疾监测与响应模式中主动病例侦查范围，并了解当前该地区人群中无症状带虫者情况。 方法 2014年7月在云南省盈江县选择存在疟疾本地感染病例的3个自然村作为调查现场。将这些本地感染病例作为线索病例，以其住所为圆心，分别以100 m、300 m、500 m和1 000 m为半径，侦查该范围内当地居住人群。收集每个被调查者耳垂血分别制作厚、薄血片各一张和滤纸血一份，采用显微镜观察和巢式PCR检测其疟原虫感染情况。 结果 共收集278例血样，显微镜观察发现3例无症状带虫者，人群中带虫率为1.1%（3/278）；巢式PCR结果发现6例无症状带虫者，人群带虫率2.2%（6/278）。依据巢式PCR结果，不同侦查半径分析表明，300 m半径范围能够发现线索病例周围人群中全部无症状带虫者，其中在101～300 m范围内发现的占66.7%。 结论 在我国中缅边境地区人群中存在一定比例无症状带虫者，巢式PCR检测方法开展侦查半径为300 m的主动病例侦查能够有效地发现人群中无症状带虫者。

Objective To explore the effective screening radii of active case detection of the 1-3-7 surveillance and response strategy， and investigate the malaria parasite rate of carriers in China-Myanmar border. Methods Three villages with indigenous malaria cases in Yingjiang County of Yunan Province were selected as study sites. The persons lived around the indigenous cases（index case） within the radius of 100 m， 300 m， 500 m， and 1 km were screened by microscopy and nested PCR. Parasite rate of asymptomatic carriers at different radii were calculated. Results Among 278 blood samples， the parasite rate of asymptomatic carriers was 1.1%（3/278） and 2.2%（6/278） using microscopy and nested PCR， respectively. Based on the results of nested PCR， all the asymptomatic carriers could be detected within a 300 m radius around the index case， and with the highest proportion（66.7%） in the radius of 101-300 m. Conclusion The asymptomatic carriers of malaria parasites in the China-Myanmar border area can be effectively detected within a 300 m screening radius of index case by using nested PCR.