Seasonal variations in Plasmodium falciparum parasite prevalence assessed by varying diagnostic tests in asymptomatic children in southern Ghana
Seasonal variations in Plasmodium falciparum parasite prevalence assessed by varying diagnostic tests in asymptomatic children in southern Ghana
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DOI：
10.1371/journal.pone.0199172
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发表时间：
2018-06-15
期刊：
影响因子：
3.7
通讯作者：
Amoah, Linda E.
中科院分区：
文献类型：
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作者：
Ayanful-Torgby, Ruth;Quashie, Neils B.;Amoah, Linda E.
表现为症状或无症状的恶性疟原虫感染可能含有对疟疾传播至关重要的有性阶段寄生虫（配子体）。在这项研究中，显微镜和亚显微镜无性和配子体寄生虫阶段的患病率进行了评估，在加纳南部的两个社区的无症状儿童。80名12岁及以下的儿童，没有一个人表现出临床疟疾的迹象，生活在Obom和Cape Coast，被抽样两次，一次在雨季（2015年7月），随后在旱季（2016年1月）。使用静脉血制备厚血涂片和薄血涂片，点疟疾快速诊断试验（PfHRP 2 RDT）以及制备滤纸血点。将血细胞沉淀保存在Trizol中用于RNA提取。采用聚合酶链反应（PCR）和半定量真实的时间逆转录酶PCR（qRT-PCR）测定亚显微寄生虫感染率。在两个研究中心，在6个月的研究期间，87%（95% CI：78-96）的无症状受试者为寄生虫阳性。在雨季，Obom的无性期和配子体期寄生虫感染率均显著高于Cape Coast（P < 0.001）。亚显微配子体患病率是最高的，在奥博姆雨季，但在海岸角的旱季。通过PCR确定的寄生虫患病率与通过qRT-PCR确定的Obom相似，但显著低于通过qRT-PCR确定的Cape Coast。寄生虫流行率不同的社区表现出配子体携带者流行率的季节性变化。在加纳南部，亚显微无症状寄生虫和配子体携带率非常高，即使在旱季，在显微寄生虫流行率低的社区也是如此，在国家监测工作中可能会被遗漏。
Plasmodium falciparum infections presenting either as symptomatic or asymptomatic may contain sexual stage parasites (gametocytes) that are crucial to malaria transmission. In this study, the prevalence of microscopic and submicroscopic asexual and gametocyte parasite stages were assessed in asymptomatic children from two communities in southern Ghana. Eighty children aged twelve years and below, none of whom exhibited signs of clinical malaria living in Obom and Cape Coast were sampled twice, one during the rainy (July 2015) and subsequently during the dry (January 2016) season. Venous blood was used to prepare thick and thin blood smears, spot a rapid malaria diagnostic test (PfHRP2 RDT) as well as prepare filter paper blood spots. Blood cell pellets were preserved in Trizol for RNA extraction. Polymerase chain reaction (PCR) and semi-quantitative real time reverse transcriptase PCR (qRT-PCR) were used to determine submicroscopic parasite prevalence. In both sites 87% (95% CI: 78-96) of the asymptomatic individuals surveyed were parasites positive during the 6 month study period. The prevalence of asexual and gametocyte stage parasites in the rainy season were both significantly higher in Obom than in Cape Coast (P < 0.001). Submicroscopic gametocyte prevalence was highest in the rainy season in Obom but in the dry season in Cape Coast. Parasite prevalence determined by PCR was similar to that determined by qRT-PCR in Obom but significantly lower than that determined by qRT-PCR in Cape Coast. Communities with varying parasite prevalence exhibit seasonal variations in the prevalence of gametocyte carriers. Submicroscopic asymptomatic parasite and gametocyte carriage is very high in southern Ghana, even during the dry season in communities with low microscopic parasite prevalence and likely to be missed during national surveillance exercises.