Schistosoma haematobium effects on Plasmodium falciparum infection modified by soil-transmitted helminths in school-age children living in rural areas of Gabon
Schistosoma haematobium effects on Plasmodium falciparum infection modified by soil-transmitted helminths in school-age children living in rural areas of Gabon
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DOI：
10.1371/journal.pntd.0006663
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发表时间：
2018-08-01
影响因子：
3.8
通讯作者：
Adegnika, Ayola Akim
中科院分区：
文献类型：
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作者：
Dejon-Agobe, Jean Claude;Zinsou, Jeannot Frejus;Adegnika, Ayola Akim
背景在撒哈拉以南地区疟疾负担仍然很高，那里的蠕虫盛行，那里的儿童经常同时感染这两种寄生虫。尽管蠕虫对疟疾感染的影响是显而易见的，但这些混合感染的影响尚未明确阐明，而且稀少的发现相互矛盾。在这项研究中，我们调查了考虑土壤传播蠕虫(STH)的血吸虫病对恶性疟原虫感染的流行和发病率的影响。方法纵向调查居住在加蓬Lambaar A ne A附近两个农村社区的学龄儿童。分别用厚血涂片光镜、尿滤过和Kato-Katz技术检测疟疾原虫、血吸虫卵和STH虫卵。在纳入时评估恶性疟原虫携带情况，并记录疟疾发病率和首次疟疾事件发生的时间与血吸虫携带情况的相关性。使用广义线性模型的分层多变量分析评估了与STH相互作用的疟原虫感染的风险，生存分析评估了疟疾的持续时间。主要发现，在受试者登记的总体患病率中，血吸虫、恶性疟原虫感染以及与这两种寄生虫混合感染的总患病率分别为30%、23%和9%。我们的结果表明，儿童血吸虫病倾向于增加感染疟原虫的风险，但与鞭虫或钩虫感染的联合作用明显增加了风险(AOR=3.9[(95%)CI：1.7~9.2])。随着时间的推移，疟疾发病率为0.51[(95%)CI：0.45~0.57]/人年，血吸虫感染者组疟疾发病率高于非感染组(0.61比0.43，P=0.02)，首次疟疾发病时间仅在6~10岁血吸虫感染者有明显延迟。结论STH可增加血吸虫病阳性儿童感染恶性疟原虫的风险，感染后血吸虫病儿童发病的易感性增加，但年龄较大的儿童不明显。
BackgroundMalaria burden remains high in the sub-Saharan region where helminths are prevalent and where children are often infected with both types of parasites. Although the effect of helminths on malaria infection is evident, the impact of these co-infections is not clearly elucidated yet and the scarce findings are conflicting. In this study, we investigated the effect of schistosomiasis, considering soil-transmitted helminths (STH), on prevalence and incidence of Plasmodium falciparum infection.MethodologyThis longitudinal survey was conducted in school-age children living in two rural communities in the vicinity of Lambare A ne A, Gabon. Thick blood smear light microscopy, urine filtration and the Kato-Katz technique were performed to detect malaria parasites, S. haematobium eggs and, STH eggs, respectively. P. falciparum carriage was assessed at inclusion, and incidence of malaria and time to the first malaria event were recorded in correlation with Schistosoma carriage status. Stratified multivariate analysis using generalized linear model was used to assess the risk of plasmodium infection considering interaction with STH, and survival analysis to assess time to malaria.Main findingsThe overall prevalence on subject enrolment was 30%, 23% and 9% for S. haematobium, P. falciparum infections and co-infection with both parasites, respectively. Our results showed that schistosomiasis in children tends to increase the risk of plasmodium infection but a combined effect with Trichuris trichiura or hookworm infection clearly increase the risk (aOR = 3.9 [(95%) CI: 1.7-9.2]). The incidence of malaria over time was 0.51[(95%) CI: 0.45-0.57] per person-year and was higher in the Schistosoma-infected group compared to the noninfected group (0.61 vs 0.43, p = 0.02), with a significant delay of time-to first-malaria event only in children aged from 6 to 10-years-old infected with Schistosoma haematobium.ConclusionsOur results suggest that STH enhance the risk for P. falciparum infection in schistosomiasis-positive children, and when infected, that schistosomiasis enhances susceptibility to developing malaria in young children but not in older children.