Folegatti Pedro M, Siqueira André M, Monteiro Wuelton M, Lacerda Marcus Vinícius G, Drakeley Chris J, Braga Érika M
Department of Immunology and Infection, London School of Hygiene & Tropical Medicine, Keppel Street, London, WC1E 7HT, UK.
Instituto Nacional de Infectologia Evandro Chagas, Fundação Oswaldo Cruz, Rio de Janeiro, RJ, Brazil.
Malar J. 2017 Mar 7;16(1):107. doi: 10.1186/s12936-017-1762-7.
Considerable success in reducing malaria incidence and mortality has been achieved in Brazil, leading to discussions over the possibility of moving towards elimination. However, more than reporting and counting clinical cases, elimination will require the use of efficient tools and strategies for measuring transmission dynamics and detecting the infectious reservoir as the primary indicators of interest for surveillance and evaluation. Because acquisition and maintenance of anti-malarial antibodies depend on parasite exposure, seroprevalence rates could be used as a reliable tool for assessing malaria endemicity and an adjunct measure for monitoring transmission in a rapid and cost-effective manner.
This systematic review synthesizes the existing literature on seroprevalence of malaria in the Brazilian Amazon Basin. Different study designs (cross-sectional surveys and longitudinal studies) with reported serological results in well-defined Brazilian populations were considered. Medline (via PubMed), EMBASE and LILACS databases were screened and the articles were included per established selection criteria. Data extraction was performed by two authors and a modified critical appraisal tool was applied to assess the quality and completeness of cross-sectional studies regarding defined variables of interest.
From 220 single records identified, 23 studies were included in this systematic review for the qualitative synthesis. Five studies reported serology results on Plasmodium falciparum, 14 papers assessed Plasmodium vivax and four articles reported results on both Plasmodium species. Considerable heterogeneity among the evaluated malarial antigens, including sporozoite and blood stage antigens, was observed. The majority of recent studies analysed IgG responses against P. vivax antigens reflecting the species distribution pattern in Brazil over the last decades. Most of the published papers were cross-sectional surveys (73.9%) and only six cohort studies were included in this review. Three studies pointed to an association between antibodies against circumsporozoite protein of both P. falciparum and P. vivax and malaria exposure. Furthermore, five out 13 cross-sectional studies evidenced a positive association between IgG antibodies to the conserved 19-kDa C-terminal region of the merozoite surface protein 1 of P. vivax (PvMSP1) and malaria exposure.
This systematic review identifies potential biomarkers of P. falciparum and P. vivax exposure in areas with variable and unstable malaria transmission in Brazil. However, this study highlights the need for standardization of further studies to provide an ideal monitoring tool to evaluate trends in malaria transmission and the effectiveness of malaria intervention programmes in Brazil. Moreover, the score-based weighted tool developed and used in this study still requires further validation.
巴西在降低疟疾发病率和死亡率方面取得了显著成效，引发了关于迈向疟疾消除可能性的讨论。然而，要实现消除疟疾，除了报告和统计临床病例外，还需要使用有效的工具和策略来衡量传播动态并检测感染源，将其作为监测和评估的主要关注指标。由于抗疟抗体的获得和维持取决于寄生虫暴露，血清阳性率可作为评估疟疾流行程度的可靠工具，以及以快速且具成本效益的方式监测传播情况的辅助措施。
本系统评价综合了巴西亚马逊盆地疟疾血清阳性率的现有文献。纳入了在明确界定的巴西人群中报告了血清学结果的不同研究设计（横断面调查和纵向研究）。对Medline（通过PubMed）、EMBASE和LILACS数据库进行了筛选，并根据既定的选择标准纳入文章。由两名作者进行数据提取，并应用一种改良的关键评估工具来评估横断面研究在感兴趣的特定变量方面的质量和完整性。
从识别出的220条单一记录中，有23项研究被纳入本系统评价进行定性综合分析。5项研究报告了恶性疟原虫的血清学结果，14篇论文评估了间日疟原虫，4篇文章报告了两种疟原虫的结果。观察到所评估的疟疾抗原（包括子孢子和血液阶段抗原）之间存在相当大的异质性。近期的大多数研究分析了针对间日疟原虫抗原的IgG反应，反映了巴西过去几十年的疟原虫种类分布模式。大多数已发表的论文是横断面调查（73.9%），本评价仅纳入了6项队列研究。3项研究指出，针对恶性疟原虫和间日疟原虫子孢子蛋白的抗体与疟疾暴露之间存在关联。此外，13项横断面研究中有5项证明，针对间日疟原虫裂殖子表面蛋白1（PvMSP1）保守的19-kDa C末端区域的IgG抗体与疟疾暴露之间存在正相关。
本系统评价确定了巴西疟疾传播多变且不稳定地区恶性疟原虫和间日疟原虫暴露的潜在生物标志物。然而，本研究强调需要进一步研究的标准化，以提供一个理想的监测工具来评估巴西疟疾传播趋势和疟疾干预计划的有效性。此外，本研究开发和使用的基于评分的加权工具仍需进一步验证。
