Comparison of blood smear, antigen detection, and nested-PCR methods for screening refugees from regions where malaria is endemic after a malaria outbreak in Quebec, Canada
Comparison of blood smear, antigen detection, and nested-PCR methods for screening refugees from regions where malaria is endemic after a malaria outbreak in Quebec, Canada
复制标题
DOI：
10.1128/jcm.42.6.2694-2700.2004
复制
发表时间：
2004-06-01
影响因子：
9.4
通讯作者：
Ward, BJ
中科院分区：
文献类型：
--
作者：
Ndao, M;Bandyayera, E;Ward, BJ
疟疾输入到非地方性流行的地区引起了许多关切，包括及时提供适当护理、血液供应的安全性以及本土传播的风险。目前还没有就筛查流动人口疟疾的最佳方式达成共识。2000年8月至2001年3月期间，535名难民从坦桑尼亚难民营抵达加拿大魁北克。在第一批224人重新安置后的4周内，麦吉尔大学热带疾病中心注意到全省爆发了疟疾（在3周内出现了15例病例）。这一组（第1组）在抵达加拿大后3至4个月期间进行了疟疾追踪和筛查。随后的106组和205组难民分别在抵达加拿大后立即（第2组）和在离开难民营之前立即（第3组）接受检查。从521名难民中获得一份edta血液样本，通过厚血涂片和薄血涂片（I组和2组）、抗原检测（ICT Malaria Pf和OptiMAL；仅1组）和巢式PCR（所有组）进行检测。总的来说，521名难民中有98人被发现感染（18.8%）。绝大多数感染（98例中有81例）仅由恶性疟原虫引起。以PCR作为“金标准”，镜检（灵敏度50%，特异性100%）和抗原检测（ICT灵敏度37.5%，ICT特异性100%，最佳灵敏度29.1%，最佳特异性95.6%）均表现不佳。pcr阳性受试者在检测时均无症状，仅有两人最近出现与疟疾相符的症状（无论是否诊断和治疗）。对来自疟疾传播严重地区的移民进行积极监测，可降低移民人口的发病风险，并减轻向东道国人口的传播。我们的数据表明，到目前为止，PCR是这种监测最强大的工具。
The importation of malaria into a region where it is not endemic raises many concerns, including the timely delivery of appropriate care, safety of the blood supply, and the risk of autochthonous transmission. There is presently no consensus on the best way to screen mobile populations for malaria. Between August 2000 and March 2001, 535 refugees arrived in Quebec, Canada, from Tanzanian camps. Within 4 weeks of resettlement of the first group of 224, the McGill University Centre for Tropical Diseases noted an outbreak of malaria across the province (15 cases over a 3-week period). This group (group 1) was traced and screened for malaria between 3 and 4 months after arrival in Canada. Subsequent groups of 106 and 205 refugees were screened immediately upon arrival in Canada (group 2) and immediately prior to their departure from refugee camps (group 3), respectively. A single EDTA-blood sample was obtained from 521 refugees for testing by thick and thin blood smears (groups I and 2), antigen detection (ICT Malaria Pf and OptiMAL; group 1 only), and nested PCR (all groups). Overall, 98 of 521 refugees were found to be infected (18.8%). The vast majority of infections (81 of 98) were caused by Plasmodium falciparum alone. Using PCR as the "gold standard," both microscopy (sensitivity, 50%; specificity, 100%) and antigen detection (ICT sensitivity, 37.5%; ICT specificity, 100%; OptiMAL sensitivity, 29.1%; OptiMAL specificity, 95.6%) performed poorly. None of the PCR-positive subjects were symptomatic at the time of testing, and only two had recently had symptoms compatible with malaria (with or without diagnosis and treatment). Active surveillance of migrants from regions of intense malaria transmission can reduce the risk of morbidity in the migrant population and mitigate against transmission to the host population. Our data demonstrate that PCR is, by far, the most powerful tool for such surveillance.