Anhui Provincial Centre for Disease Control and Prevention, Hefei 230601, China.
School Health Service Management, Anhui Medical University, Hefei 230032, China.
Acta Trop. 2021 Oct;222:106042. doi: 10.1016/j.actatropica.2021.106042. Epub 2021 Jul 10.
In the Anhui Province, China, efforts to interrupt the local malaria transmission were successful, with no endemic cases reported since 2014. Contrastingly, imported malaria cases are still being reported, indicating a disease reintroduction risk after years of elimination. A good surveillance system is key for avoiding the risk, detecting imported cases and possible cases associated with local transmission early. Therefore, rapid diagnostic tests (RDTs) were combined with microscopy to strengthen malaria surveillance in the province. Herein, we aimed to evaluate the efficacy of this surveillance strategy.
We conducted a retrospective study using malaria surveillance data from January 2016 to June 2020. Epidemiological characteristics and diagnostic information were analysed using descriptive and comparative statistics. The diagnostic performance of the combined toolbox (Wondfo RDTs plus microscopy) was evaluated based on its sensitivity, specificity, positive and negative predictive values, and Cohen's kappa coefficient, using real-time polymerase chain reaction as the gold standard.
The combined toolbox displayed a higher overall sensitivity for malaria cases than that of microscopy alone (93.74% vs 89.37%; p <0.05), which could detect 94.65%, 88.16%, 95.00%, and 100.00% of Plasmodium falciparum, P. ovale, P. vivax, and P. malariae infections, respectively. In clinical practice, Wondfo RDTs ability to detect P. falciparum infections was better than that of microscopy (97.55% vs 89.67%, p < 0.05). In contrast, microscopy displayed a higher specificity than that of Wondfo RDTs (81.82% vs 63.28%, p <0.05). Moreover, the consistency between microscopy and the gold standard results was also better than that of RDTs (Kappa value:0.669 vs 0.596).
The combination of microscopy and RDTs is an effective strategy for malaria surveillance because it possibly detected more P. falciparum infections due to the introduction of RDTs. In contrast, microscopy is complementary to some limitations related to the use of RDTs in field practice. Thus, monitoring malaria cases in non-endemic areas may require employing more than one diagnostic tool in surveillance strategies. Moreover, further understanding of the advantages and disadvantages of different detection methods is necessary for applying optimum combinations in field settings.
在中国安徽省，当地疟疾传播的阻断工作取得成功，自 2014 年以来未报告本地疟疾病例。相比之下，仍有输入性疟疾病例报告，表明消除疟疾多年后存在疾病再输入的风险。一个良好的监测系统是避免这种风险的关键，可以早期发现输入性病例和可能与本地传播相关的病例。因此，在该省，快速诊断检测（RDT）与显微镜检查相结合，以加强疟疾监测。在此，我们旨在评估该监测策略的效果。
我们使用 2016 年 1 月至 2020 年 6 月的疟疾监测数据进行了回顾性研究。采用描述性和比较性统计方法分析了流行病学特征和诊断信息。根据实时聚合酶链反应作为金标准，评估了联合检测工具箱（万孚 RDT 加显微镜检查）的诊断性能，包括敏感性、特异性、阳性和阴性预测值以及 Cohen's kappa 系数。
联合检测工具箱对疟疾病例的总体敏感性高于单独使用显微镜检查（93.74%比 89.37%；p<0.05），可以检测到 94.65%、88.16%、95.00%和 100.00%的恶性疟原虫、卵形疟原虫、间日疟原虫和三日疟原虫感染。在临床实践中，万孚 RDT 检测恶性疟原虫感染的能力优于显微镜检查（97.55%比 89.67%，p<0.05）。相比之下，显微镜检查的特异性高于万孚 RDT（81.82%比 63.28%，p<0.05）。此外，显微镜检查与金标准结果的一致性也优于 RDT（Kappa 值：0.669 比 0.596）。
显微镜检查和 RDT 相结合是一种有效的疟疾监测策略，因为引入 RDT 后可能检测到更多的恶性疟原虫感染。相比之下，显微镜检查是对 RDT 在现场实践中使用的一些局限性的补充。因此，在非流行地区监测疟疾病例可能需要在监测策略中使用不止一种诊断工具。此外，为了在现场环境中应用最佳组合，需要进一步了解不同检测方法的优缺点。
