Common asymptomatic and submicroscopic malaria infections in Western Thailand revealed in longitudinal molecular and serological studies: a challenge to malaria elimination.
Common asymptomatic and submicroscopic malaria infections in Western Thailand revealed in longitudinal molecular and serological studies: a challenge to malaria elimination.
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DOI：
10.1186/s12936-016-1393-4
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发表时间：
2016-06-22
期刊：
影响因子：
3
通讯作者：
Yan G
中科院分区：
文献类型：
--
作者：
Baum E;Sattabongkot J;Sirichaisinthop J;Kiattibutr K;Jain A;Taghavian O;Lee MC;Huw Davies D;Cui L;Felgner PL;Yan G
尽管控制工作取得了很大成功，但疟疾仍然是泰国的一个重大公共卫生问题。根据显微镜检查，曾经是泰国最高负担地区的西北部Tak省现在被认为是低传播地区。然而，显微镜对检测低水平寄生虫血症不敏感，导致在大多数感染为亚显性的地区，寄生虫流行率严重低估。本研究的目的是利用分子和血清学检测方法评估当前疟疾流行病学，并分析抗疟原虫抗体反应与感染期间的年龄、季节变化和临床表现的关系。在哨点村和医院发热病人中进行了三次全面的横断面调查，并采集了从婴儿到老年人的全血样本。从细胞分离的基因组DNA中进行定量pcr筛选，发现存在恶性疟原虫、间日疟原虫、疟疾疟原虫、卵形疟原虫和诺氏疟原虫。在蛋白芯片上检测血浆样本以获得来自同一个体的抗体反应谱。在研究的群落中，90.2%的疟原虫感染为亚微观和无症状，包括大量的混合种感染。在发热患者中，混合物种感染占阳性病例的68%，所有这些病例都被误诊和治疗不足。所有检测样本均显示对疟原虫抗原的血清学反应性。在恶性疟原虫和间日疟原虫的抗体获得率上存在显著差异，在物种特异性免疫优势应答上存在年龄相关差异。在10个月的研究期间，抗疟原虫抗体增加。发热患者的抗体反应强于无症状感染者。尽管疟疾流行率大幅下降，但传播仍在以传统方法无法检测到的水平继续进行。由于目前的监测方法侧重于病例管理，如果不发现和治疗无症状亚显微镜感染，泰国的疟疾传播将不会中断。本文的在线版本（doi:10.1186/s12936-016-1393-4）包含补充材料，可供授权用户使用。
Despite largely successful control efforts, malaria remains a significant public health problem in Thailand. Based on microscopy, the northwestern province of Tak, once Thailand’s highest burden area, is now considered a low-transmission region. However, microscopy is insensitive to detect low-level parasitaemia, causing gross underestimation of parasite prevalence in areas where most infections are subpatent. The objective of this study was to assess the current epidemiology of malaria prevalence using molecular and serological detection methods, and to profile the antibody responses against Plasmodium as it relates to age, seasonal changes and clinical manifestations during infection. Three comprehensive cross-sectional surveys were performed in a sentinel village and from febrile hospital patients, and whole blood samples were collected from infants to elderly adults. Genomic DNA isolated from cellular fraction was screened by quantitative-PCR for the presence of Plasmodium falciparum, Plasmodium vivax, Plasmodium malariae, Plasmodium ovale and Plasmodium knowlesi. Plasma samples were probed on protein microarray to obtain antibody response profiles from the same individuals. Within the studied community, 90.2 % of Plasmodium infections were submicroscopic and asymptomatic, including a large number of mixed-species infections. Amongst febrile patients, mixed-species infections comprised 68 % of positive cases, all of which went misdiagnosed and undertreated. All samples tested showed serological reactivity to Plasmodium antigens. There were significant differences in the rates of antibody acquisition against P. falciparum and P. vivax, and age-related differences in species-specific immunodominance of response. Antibodies against Plasmodium increased along the ten-month study period. Febrile patients had stronger antibody responses than asymptomatic carriers. Despite a great decline in malaria prevalence, transmission is still ongoing at levels undetectable by traditional methods. As current surveillance methods focus on case management, malaria transmission in Thailand will not be interrupted if asymptomatic submicroscopic infections are not detected and treated. The online version of this article (doi:10.1186/s12936-016-1393-4) contains supplementary material, which is available to authorized users.