Defining the relationship between Plasmodium vivax parasite rate and clinical disease
Defining the relationship between Plasmodium vivax parasite rate and clinical disease
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DOI：
10.1186/s12936-015-0706-3
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发表时间：
2015-05-07
期刊：
影响因子：
3
通讯作者：
Hay, Simon I.
中科院分区：
文献类型：
--
作者：
Battle, Katherine E.;Cameron, Ewan;Hay, Simon I.
背景：尽管对于国家疟疾控制规划的制定和评估至关重要，但在当地监测系统不完善的情况下，准确计算疟疾流行国家的临床疾病负担仍然具有挑战性。从寄生虫流行率调查汇编推断年发病率的策略已被证明对恶性疟原虫的具体情况有效，但尚未针对间日疟原虫制定。此外，确定间日疟原虫流行率与临床发病率之间的关系还可以推断出信息平衡相反的地区的流行程度，即事件病例数比寄生虫调查收集得更广泛；这两种应用最终都有助于对间日疟原虫传播强度及其疾病负担进行制图估计。方法：进行了主动病例检测调查的搜索，将记录的发病率值与当地当代寄生虫率测量值相匹配，并分类为不同复发表型的地理区域。对这些数据拟合分层贝叶斯模型，以量化患病率和发病率之间的关系，同时考虑复发区域之间的差异。结果：该模型拟合了 176 个同时测量的间日疟原虫发病率和患病率记录，是发病率对数与年龄标准化患病率对数的线性回归。绘制了可获得数据的六个复发区域的具体关系，以及汇总的总体关系。不同复发区域的曲线斜率各不相同；预测复发时间短的区域比观察到的包含长潜伏期复发表型的区域具有更陡的斜率。 结论：拟合关系以及适当的不确定性指标允许根据可获得的间日疟原虫流行率数据来估计已知置信度的临床发病率。这是基于制图推断间日疟原虫引起的全球发病率的先决条件，该推断将用于为控制工作提供信息。
Background: Though essential to the development and evaluation of national malaria control programmes, precise enumeration of the clinical illness burden of malaria in endemic countries remains challenging where local surveillance systems are incomplete. Strategies to infer annual incidence rates from parasite prevalence survey compilations have proven effective in the specific case of Plasmodium falciparum, but have yet to be developed for Plasmodium vivax. Moreover, defining the relationship between Plasmodium vivax prevalence and clinical incidence may also allow levels of endemicity to be inferred for areas where the information balance is reversed, that is, incident case numbers are more widely gathered than parasite surveys; both applications ultimately facilitating cartographic estimates of Plasmodium vivax transmission intensity and its ensuring disease burden.Methods: A search for active case detection surveys was conducted and the recorded incidence values were matched to local, contemporary parasite rate measures and classified to geographic zones of differing relapse phenotypes. A hierarchical Bayesian model was fitted to these data to quantify the relationship between prevalence and incidence while accounting for variation among relapse zones.Results: The model, fitted with 176 concurrently measured Plasmodium vivax incidence and prevalence records, was a linear regression of the logarithm of incidence against the logarithm of age-standardized prevalence. Specific relationships for the six relapse zones where data were available were drawn, as well as a pooled overall relationship. The slope of the curves varied among relapse zones; zones with short predicted time to relapse had steeper slopes than those observed to contain long-latency relapse phenotypes.Conclusions: The fitted relationships, along with appropriate uncertainty metrics, allow for estimates of clinical incidence of known confidence to be made from wherever Plasmodium vivax prevalence data are available. This is a prerequisite for cartographic-based inferences about the global burden of morbidity due to Plasmodium vivax, which will be used to inform control efforts.