Anti-sporozoite antibodies as alternative markers for malaria transmission intensity estimation
Anti-sporozoite antibodies as alternative markers for malaria transmission intensity estimation
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DOI：
10.1186/1475-2875-13-103
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发表时间：
2014-03-17
期刊：
影响因子：
3
通讯作者：
Koram, Kwadwo A.
中科院分区：
文献类型：
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作者：
Kusi, Kwadwo A.;Bosomprah, Samuel;Koram, Kwadwo A.
背景资料：全球报告的疟疾病例继续下降，这是由于战略性地实施了多种疟疾控制工具。然而，需要通过持续监测来保持已取得的成果，以确保消除和根除疟疾。昆虫接种率目前是传播监测的标准工具，但这还不够灵敏，特别是在传播率极低的地区。传播估计模型的基础上血清转换率（λ）的抗体恶性疟原虫血液阶段抗原的相关性。λ的估计，这是传输强度的措施，与EIR相关，但受到血液阶段抗原抗体的长期持久性的限制。子孢子抗原的抗体的血清阳性率可能是更好的选择，因为这些抗原通常具有较短的免疫暴露时间。本研究的目的是建立基于两种恶性疟原虫子孢子抗原（CSP、CelTOS）抗体血清阳性率的传播估计模型，并与基于经典血液阶段抗原AMA1的模型进行比较。方法：采用间接ELISA法评估2009年在加纳南部低传播区进行的3次横断面调查中存档血浆中的抗体水平。对CSP，CelTOS和AMA1的抗体的血清阳性率进行了拟合可逆催化模型，以估计λ和相应的血清逆转率（rho）为每个antibody.Results：开发的三个模型，抗CSP模型预测的λ下降13倍前四年的采样时间（2009年）。抗AMA1抗体形成的速率比抗CelTOS抗体和抗CSP抗体在λ降低期间的速率高四倍。相比之下，抗AMA1抗体的衰减速率相对于抗CSP抗体的衰减速率慢五倍，而抗AMA1和抗CelTOS抗体的衰减速率没有显著差异。抗CSP抗体的寿命相对较短，因为它们形成在一个11.6倍的速度较慢，相对于他们的衰减期间减少λ。结论：抗CSP抗体的这些功能可以被利用的发展模型预测季节性的，短期的变化，在疟疾流行地区的传播强度，特别是消除阶段的疟疾控制接近。
Background: Reported malaria cases continue to decline globally, and this has been attributed to strategic implementation of multiple malaria control tools. Gains made would however need to be sustained through continuous monitoring to ensure malaria elimination and eradication. Entomological inoculation rate (EIR) is currently the standard tool for transmission monitoring but this is not sensitive enough, especially in areas of very low transmission. Transmission estimation models based on seroconversion rates (lambda) of antibodies to Plasmodium falciparum blood stage antigens are gaining relevance. Estimates of lambda, which is the measure of transmission intensity, correlate with EIR but are limited by long-term persistence of antibodies to blood stage antigens. Seroprevalence of antibodies to sporozoite antigens may be better alternatives since these antigens usually have shorter immune exposure times. The aim of this study was to develop transmission estimation models based on the seroprevalence of antibodies to two P. falciparum sporozoite antigens (CSP, CelTOS) and compare with models based on the classical blood stage antigen AMA1.Methods: Antibody levels in archived plasma from three cross-sectional surveys conducted in 2009 in a low transmission area of Southern Ghana were assessed by indirect ELISA. Seroprevalence of antibodies against CSP, CelTOS and AMA1 were fitted to reversible catalytic models to estimate lambda and corresponding seroreversion rates (rho) for each antibody.Results: Of the three models developed, the anti-CSP model predicted a 13-fold decrease in lambda four years prior to the time of sampling (2009). Anti-AMA1 antibodies formed at a four-fold greater rate compared to that of anti-CelTOS antibodies, and anti-CSP antibodies during the period of decreased lambda. In contrast, anti-AMA1 antibodies decayed at a five-fold slower rate relative to that of anti-CSP antibodies while anti-AMA1 and anti-CelTOS antibody decay rates were not significantly different. Anti-CSP antibodies were relatively short-lived as they formed at an 11.6-fold slower rate relative to their decay during the period of decreased lambda.Conclusions: These features of anti-CSP antibodies can be exploited for the development of models for predicting seasonal, short-term changes in transmission intensity in malaria-endemic areas, especially as the elimination phase of malaria control is approached.