Asymptomatic Plasmodium falciparum infections and determinants of carriage in a seasonal malaria chemoprevention setting in Northern Cameroon and south Senegal (Kedougou).

IF 2.4 3区 医学 Q3 INFECTIOUS DISEASES Malaria Journal Pub Date : 2024-12-18 DOI:10.1186/s12936-024-05150-3
Innocent M Ali, Isaac A Manga, Akindeh M Nji, Valery P Tchuenkam, Peter Thelma Ngwa Neba, Dorothy F Achu, Jude D Bigoga, Babacar Faye, Cally Roper, Colin J Sutherland, Wilfred F Mbacham
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Abstract

Background: Among the several strategies recommended for the fight against malaria, seasonal malaria chemoprevention (SMC) with sulfadoxine-pyrimethamine and amodiaquine combination (SPAQ) targets children 3 months to 5 years in Sahel regions of Africa to reduce mortality and mortality. Since SMC with SPAQ is administered to symptoms-free children for prevention of malaria, it is anticipated that a proportion of asymptomatic parasitaemic children will also be treated and may result in a drop in both the overall population prevalence of asymptomatic malaria infections, subsequent risk of symptomatic malaria infections and transmission. Age-specific carriage of asymptomatic Plasmodium spp. infections (API) was evaluated in target children and adults in Cameroon and Senegal, prior to the 2018 SMC campaign in both countries.

Methods: A baseline household survey was carried out in August 2018 in two areas in Cameroon and one in Senegal just before the beginning of distribution of SPAQ for SMC. The survey included collection of fingerpick blood for malaria rapid diagnostic testing (RDT) and administration of a pre-tested questionnaire on demographics and malaria risk factors to participants. The age-specific prevalence of API in all study sites was analysed, first as a distribution of RDT-positives in 5-year age categories and secondly, with age as a continuous variable in the whole sample, using the Wilcoxon rank sum test. Risk factors for carriage of asymptomatic infections were examined using logistic regression analysis in STATA v.16 and Rv4.1.2.

Results: In total, 6098 participants were surveyed. In Cameroon, overall prevalence of API was 34.0% (32.1-36.0%) in Adamaoua, and 43.5% (41.0-45.7%) in the North. The median age of RDT positivity was higher in Senegal: 11 years (IQR 7-16) than in Cameroon-Adamaoua: 8 years (4-17) and North: 8 years (4-12) and significantly different between the three study regions. In all three study sites, asymptomatic carriage was significantly higher in the older age group (5-10 in Cameroon, and 7-14 in Senegal), compared to the younger age group, although the median age of participants was lower among RDT-negatives in the North compared to RDT-positives. Health area, gender and last infection within past year significantly confounded the relationship between age and parasite carriage in Adamaoua and Senegal but not in North Cameroon. Absence of bed net and previous infection within one month of the survey all independently predicted carriage of asymptomatic parasites in multivariate regression analysis.

Conclusion: Under five years asymptomatic Plasmodium infection in northern Cameroon prior to SMC season remained high in 2018, irrespective of history of SMC implementation in the study areas in Cameroon. Compared to Adamaoua, peak asymptomatic malaria parasite rate was observed in children 5-10 years, which is out of the SMC target age-range. Health area, last infection within the past month and to a lesser extent gender affected the association between age and asymptomatic carriage in all sites except the North region of Cameroon, indicating wide heterogeneity in risk of malaria among the general population in that geography. Follow-up studies designed to measure SMC effects in Cameroon are warranted as it may become necessary to extend age of SMC eligibility to 10 years, as is practiced in Senegal.

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喀麦隆北部和塞内加尔南部季节性疟疾化学预防环境中无症状恶性疟原虫感染和携带决定因素(凯杜古)。
背景:在建议的几种防治疟疾战略中,磺胺多辛-乙胺嘧啶和阿莫地喹联合使用的季节性疟疾化学预防(SMC)针对非洲萨赫勒地区3个月至5岁的儿童,以降低死亡率和死亡率。由于给无症状的儿童注射含SPAQ的SMC以预防疟疾,预计一部分无症状的寄生虫病儿童也将得到治疗,并可能导致无症状疟疾感染的总体人口流行率、随后的有症状疟疾感染和传播风险下降。在喀麦隆和塞内加尔的2018年SMC运动之前,在两国的目标儿童和成人中评估了无症状疟原虫感染(API)的年龄特异性携带情况。方法:2018年8月,在喀麦隆的两个地区和塞内加尔的一个地区,在SMC的SPAQ开始分发之前,进行了基线家庭调查。该调查包括采集指尖血样用于疟疾快速诊断测试(RDT),并向参与者发放一份预测试的人口统计和疟疾风险因素问卷。分析所有研究地点API的年龄特异性患病率,首先作为5岁年龄组rdt阳性的分布,其次,使用Wilcoxon秩和检验,将年龄作为整个样本的连续变量。在STATA v.16和Rv4.1.2中使用逻辑回归分析检查无症状感染携带的危险因素。结果:共调查了6098名参与者。在喀麦隆,阿达马乌瓦的API总患病率为34.0%(32.1-36.0%),北部为43.5%(41.0-45.7%)。塞内加尔的RDT阳性中位年龄为11岁(IQR 7-16),高于喀麦隆-阿达马乌瓦的8岁(4-17)和北方的8岁(4-12),且在三个研究区域之间存在显著差异。在所有三个研究地点,与年轻年龄组相比,老年组(喀麦隆5-10岁,塞内加尔7-14岁)的无症状携带明显更高,尽管北方rdt阴性参与者的中位年龄低于rdt阳性参与者。在阿达马乌瓦和塞内加尔,卫生地区、性别和过去一年内的最后一次感染严重混淆了年龄与寄生虫携带之间的关系,但在喀麦隆北部却没有。多因素回归分析显示,未使用蚊帐和调查后一个月内有过感染均可独立预测无症状寄生虫的携带情况。结论:无论喀麦隆研究地区是否有SMC实施史,2018年喀麦隆北部5岁以下无症状疟原虫感染在SMC季节前仍然很高。与Adamaoua相比,在5-10岁的儿童中观察到无症状疟疾寄生虫率的高峰,这超出了SMC的目标年龄范围。除喀麦隆北部地区外,卫生领域、过去一个月内的最后一次感染以及性别在较小程度上影响了年龄与无症状携带之间的关系,这表明该地区一般人口的疟疾风险存在很大的异质性。喀麦隆有必要进行旨在衡量SMC效果的后续研究,因为可能有必要将SMC资格年龄延长至10岁,就像塞内加尔的做法一样。
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来源期刊
Malaria Journal
Malaria Journal 医学-寄生虫学
CiteScore
5.10
自引率
23.30%
发文量
334
审稿时长
2-4 weeks
期刊介绍: Malaria Journal is aimed at the scientific community interested in malaria in its broadest sense. It is the only journal that publishes exclusively articles on malaria and, as such, it aims to bring together knowledge from the different specialities involved in this very broad discipline, from the bench to the bedside and to the field.
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