中缅边境居民疟疾感染的疟原虫抗原检测、镜检和PCR筛查

Screening for malaria infection in residents on the China-Myanmar border:RDT,microscopy and PCR

目的 了解云南省沧源县抵边村寨居民和境外周边居民疟疾感染情况,比较疟原虫抗原检测(RDT)、镜检和PCR在低疟区和消除区居民疟疾筛查效果,为预防疟疾消除后再输入提供依据。方法 2020年8月—2021年3月,在中缅边境地区云南省临沧市沧源佤族自治县班老乡、缅甸掸邦第二特区勐冒县班歪区梅不老乡、缅甸掸邦第二特区南邓特区拥摸和大岩乡3个调查点,采集调查对象指尖血,运用RDT、疟原虫显微镜检查法、荧光定量PCR与巢式PCR法检测疟原虫感染情况。结果 共采集1 040人份血样,含中国居民606人、缅甸居民434人。其中男性506人,女性534人,年龄0~<5、5~<15、15~<30、30~<45、45~<60和≥60岁分别有51、283、187、232、205和82人。经疟原虫抗原检测试剂盒法检测1 040人均为阴性,疟原虫显微镜检查法检出间日疟阳性1份,疟原虫检出率为0.10%,荧光定量PCR与巢式PCR检出间日疟阳性1份,疟原虫检出率为0.10%。其中,缅甸掸邦第二特区勐冒县班歪区梅不老乡检出间日疟1例,疟原虫检出率为0.35%,云南省临沧市沧源佤族自治县班老乡和缅甸掸邦第二特区南邓特区拥摸和大岩乡疟原虫检出率均为0。3个调查点的疟原虫检出率差异无统计学意义(Fisher确切概率法,P>0.05),筛查中发现缅甸掸邦第二特区勐冒县班歪区1例6岁女童间日疟无症状感染者。结论 RDT不适合低疟区和消除区居民疟疾筛查,可采用镜检和PCR筛查,但PCR操作复杂成本较高;境外周边仍有疟疾流行,沧源县抵边村寨无疟疾传染源,但存在输入中风险,应及时有效防止输入再传播。

ObjectiveTo compare the screening effects of RDT,microscopy and PCR for malaria among residents in low malaria areas and elimination areas,and to investigate the presence of malaria in residents of border Villages in Cangyuan Va County and asymptomatic infections in surrounding areas,providing a basis for preventing re-introduction of malaria after elimination.MethodsFrom August 2020 to March 2021,the fingertip blood of the investigated subjects was collected from three survey sites in the border area between China and Myanmar,namely Banlao Township in Cangyuan Va Autonomous County of Lincang City,Banwai District,Mengmao County,the Second Special Zone of Shan State,Myanmar,Yongmo and Dayan Township,Nandeng Special Zone,the Second Special Zone of Shan State,Myanmar.The malaria parasite antigen detection test kit,malaria parasite microscopic examination,fluorescent quantitative PCR and nested PCR were used to detect the asymptomatic infection of malaria parasites.ResultsA total of 1040 blood samples were collected,including 606 from China and 434 from Myanmar,with 506 males and 534 females.Among them,,there were 51 individuals aged 0 to<5 years,283 aged 5 to<years,187 aged 15 to<years,232 aged 30 to<45 years,205 aged 45 to<years,and 82 aged≥60 years.All 1040 people tested negative for plasmodium antigen detection kit.One case of Plasmodium vivax detected by plasmodium microscopic etiology,with a detection rate of 0.10%.One case of P.vivax was also detected by fluorescent quantitative PCR and nested PCR,with a detection rate of 0.10%.Among them,one case of P.vivax was detected in Banwai District,Mengmao County,the Second Special Zone of Shan State,Myanmar,with a detection rate of 0.35%.The detection rates of malaria parasites in Banlao Township in Cangyuan Va Autonomous County of Lincang City,Yunnan Province and Yongmo Township and Dayan Township,Nandeng Special District,the Second Special Zone of Shan State,Myanmar were both 0.The difference in the detection rate of malaria parasites among the three survey sites was not statistically significant(χ^(2)=2.682,P>0.05).The asymptomatic P.vivax infection was detected in a 6-year-old girl from Banwai District,Mengmao County,the Second Special Zone of Shan State,Myanmar.ConclusionsRDT is not suitable for malaria screening in low malaria area and elimination area.Microscopic examination and PCR can be used for malaria screening,but PCR operation is complex and costly.In surrounding areas outside of China,malaria is still prevalent,while there is no source of malaria infection in border villages of Cangyuan Va County.However,there is a risk of importation,and timely and effective measures should be taken to prevent re-introduction and transmission.