Degarege Abraham, Veledar Emir, Degarege Dawit, Erko Berhanu, Nacher Mathieu, Madhivanan Purnima
Department of Epidemiology, Robert Stemple College of Public Health, Florida International University, Miami, USA.
Aklilu Lemma Institute of Pathobiology, Addis Ababa University, Addis Ababa, Ethiopia.
Parasit Vectors. 2016 Jun 15;9(1):344. doi: 10.1186/s13071-016-1594-2.
The epidemiology of soil-transmitted helminth (STH) and Plasmodium co-infections need better understanding. The findings of the individual studies are inconclusive. A systematic review was conducted to synthesize evidence on the association of STH infection with the prevalence and density of Plasmodium falciparum infection, and its effect on anaemia among children in sub-Saharan Africa (SSA).
Relevant studies published before March 6, 2015 were identified by searching Medline (via Pubmed), Embase, Cochrane Library and CINAHL without any language restriction. Studies on P. falciparum and STH co-infection among children in SSA except for case studies were included in this study. Studies were screened for eligibility and data extracted independently by two authors. The primary outcome assessed was the prevalence of P. falciparum infection and the secondary outcomes included P. falciparum density and prevalence of anaemia. Heterogeneity was assessed using Cochrane Q and Moran's I (2) and publication bias was evaluated using Egger test. A random-effects model was used to estimate the summary odds ratio (OR) and the corresponding 95 % confidence intervals (CI).
Out of 2985 articles screened, 11 articles were included in the systematic review; of these seven were considered in the meta-analysis. Of the 11 studies with 7458 study participants, seven were cross-sectional, one prospective cohort and three were randomized controlled trials. Four studies examined the outcome for hookworms, one for Ascaris lumbricoides and six for pooled (at least one) STH species. Eight studies measured prevalence/incidence of uncomplicated P. falciparum infection, two calculated prevalence of asymptomatic P. falciparum infection, three evaluated P. falciparum density and four considered prevalence of P. falciparum infection related anaemia/mean haemoglobin reduction. The odds of asymptomatic/uncomplicated P. falciparum infection were higher among children infected with STH than those uninfected with intestinal helminths (summary Odds Ratio [OR]: 1.4; 95 % Confidence Interval [CI]: 1.05-1.87; I (2) = 36.8 %). Plasmodium falciparum density tended to be higher among children infected with STH than those uninfected with intestinal helminths. However, STH infection was associated with lower odds of P. falciparum infection related anaemia (summary OR: 0.5; 95 % CI: 0.21-0.78; I (2) = 43.3 %).
The findings suggest that STH infection may increase susceptibility to asymptomatic/uncomplicated P. falciparum infection but may protect malaria-related anaemia in children. Future studies should investigate the effect of STH infection upon the incidence of severe P. falciparum infection among children in SSA.
土壤传播的蠕虫（STH）与疟原虫合并感染的流行病学情况需要更深入了解。各项独立研究的结果尚无定论。开展了一项系统综述，以综合关于撒哈拉以南非洲（SSA）地区儿童中STH感染与恶性疟原虫感染的患病率及密度之间的关联，以及其对贫血影响的证据。
通过检索Medline（经由PubMed）、Embase、Cochrane图书馆和CINAHL来识别2015年3月6日前发表的相关研究，无语言限制。本研究纳入了除病例研究外关于SSA地区儿童中恶性疟原虫与STH合并感染的研究。由两名作者独立筛选研究的合格性并提取数据。评估的主要结局是恶性疟原虫感染的患病率，次要结局包括恶性疟原虫密度和贫血患病率。使用Cochrane Q和Moran's I²评估异质性，使用Egger检验评估发表偏倚。采用随机效应模型来估计汇总比值比（OR）及相应的95%置信区间（CI）。
在筛选的2985篇文章中，11篇被纳入系统综述；其中7篇纳入荟萃分析。在这11项有7458名研究参与者的研究中，7项为横断面研究，1项为前瞻性队列研究，3项为随机对照试验。4项研究检测了钩虫的结局，1项检测蛔虫的结局，6项检测合并（至少一种）STH种类的结局。8项研究测量了非复杂性恶性疟原虫感染的患病率/发病率，2项计算了无症状恶性疟原虫感染的患病率，3项评估了恶性疟原虫密度，4项考虑了恶性疟原虫感染相关贫血的患病率/平均血红蛋白降低情况。感染STH的儿童发生无症状/非复杂性恶性疟原虫感染的几率高于未感染肠道蠕虫的儿童（汇总比值比[OR]：1.4；95%置信区间[CI]：1.05 - 1.87；I² = 36.8%）。感染STH的儿童的恶性疟原虫密度往往高于未感染肠道蠕虫的儿童。然而，STH感染与恶性疟原虫感染相关贫血的较低几率相关（汇总OR：0.5；95% CI：0.21 - 0.78；I² = 43.3%）。
研究结果表明，STH感染可能增加儿童对无症状/非复杂性恶性疟原虫感染的易感性，但可能对疟疾相关贫血起到保护作用。未来研究应调查STH感染对SSA地区儿童中严重恶性疟原虫感染发病率的影响。
