巢式 PCR 检测在印度中央邦曼德拉疟疾消除示范项目发热患者中检测低密度疟疾感染的意义。

Significance of nested PCR testing for the detection of low-density malaria infection amongst febrile patients from the Malaria Elimination Demonstration Project in Mandla, Madhya Pradesh, India.

机构信息

Indian Council of Medical Research - National Institute of Research in Tribal Health (ICMR-NIRTH), Jabalpur, Madhya Pradesh, India.

Indian Council of Medical Research - National Institute of Malaria Research (ICMR-NIMR), New Delhi, India.

出版信息

Malar J. 2022 Nov 17;21(1):341. doi: 10.1186/s12936-022-04355-8.

DOI:10.1186/s12936-022-04355-8

PMID:36397072

原文链接:https://pmc.ncbi.nlm.nih.gov/articles/PMC9669540/

Abstract

BACKGROUND

Low-density malaria infections (LDMI) are defined as infections that are missed by the rapid diagnostic test (RDT) and/or microscopy which can lead to continued transmission and poses a challenge in malaria elimination efforts. This study was conducted to investigate the prevalence of LDMI in febrile cases using species-specific nested Polymerase Chain Reaction (PCR) tests in the Malaria Elimination Demonstration Project, where routine diagnosis was conducted using RDT.

METHODS

Every 10th fever case from a cross-sectional community based fever surveillance was tested with RDT, microscopy and nested PCR. Parasite DNA was isolated from the filter paper using Chelex based method. Molecular diagnosis by nested PCR was performed targeting 18SrRNA gene for Plasmodium species.

RESULTS

The prevalence of malaria was 2.50% (436/17405) diagnosed by PCR, 1.13% (196/17405) by RDT, and 0.68% (118/ 17,405) by microscopy. Amongst 17,405 febrile samples, the prevalence of LDMI was 1.51% (263/17405) (95% CI 1.33-1.70), which were missed by conventional methods. Logistic regression analysis revealed that illness during summer season [OR = 1.90 (p < 0.05)] and cases screened within three days of febrile illness [OR = 5.27 (p < 0.001)] were the statistically significant predictors of LDMI.

CONCLUSION

The prevalence of malaria among febrile cases using PCR was 2.50% (436/17405) as compared to 1.13% (196/17405) by RDT. Higher number of the LDMI cases were found in subjects with ≤ 3 days mean duration of reported fever, which was statistically significant (p < 0.001). This observation suggests that an early detection of malaria with a more sensitive diagnostic method or repeat testing of the all negative cases may be useful for curtailing malaria transmission. Therefore, malaria elimination programme would benefit from using more sensitive and specific diagnostic methods, such as PCR.

摘要

背景

低密度疟原虫感染（LDMI）是指快速诊断检测（RDT）和/或显微镜检查漏检的感染，这可能导致持续传播，并对疟疾消除工作构成挑战。本研究旨在使用针对种特异性的巢式聚合酶链反应（PCR）检测，调查在疟疾消除示范项目中发热病例中的 LDMI 患病率，该项目常规诊断使用 RDT。

方法

采用横断面社区发热监测的第 10 例发热病例进行 RDT、显微镜检查和巢式 PCR 检测。使用 Chelex 法从滤纸上提取寄生虫 DNA。通过针对 18SrRNA 基因的巢式 PCR 进行分子诊断以确定疟原虫种。

结果

PCR 诊断的疟疾患病率为 2.50%（436/17405），RDT 为 1.13%（196/17405），显微镜检查为 0.68%（118/17405）。在 17405 例发热样本中，LDMI 的患病率为 1.51%（263/17405）（95%CI 1.33-1.70），这些感染漏检于常规方法。Logistic 回归分析显示，夏季发病[OR=1.90（p<0.05）]和发热后 3 天内筛查的病例[OR=5.27（p<0.001）]是 LDMI 的统计学显著预测因子。

结论

与 RDT 相比，PCR 检测发热病例中的疟疾患病率为 2.50%（436/17405）。在发热时间≤3 天的患者中发现了更多的 LDMI 病例，这具有统计学意义（p<0.001）。这一观察结果表明，使用更敏感的诊断方法或对所有阴性病例进行重复检测可能有助于遏制疟疾传播，从而早期发现疟疾。因此，疟疾消除规划将受益于使用更敏感和特异的诊断方法，如 PCR。