Prevalence of Plasmodium falciparum gametocytaemia in asymptomatic school children before and after treatment with dihydroartemisinin-piperaquine (DP)

IF 2 Q3 INFECTIOUS DISEASES

Parasite Epidemiology and Control Pub Date : 2023-05-01 DOI:10.1016/j.parepi.2023.e00292

Bismarck Dinko , Dennis Awuah , Kwadwo Boampong , John A. Larbi , Teun Bousema , Colin J. Sutherland

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引用次数: 0

Abstract

Background

Asymptomatic Plasmodium carriers form the majority of malaria-infected individuals in most endemic areas. A proportion of these asymptomatically infected individuals carry gametocytes, the transmissible stages of malaria parasites, that sustain human to mosquito transmission. Few studies examine gametocytaemia in asymptomatic school children who may form an important reservoir for transmission. We assessed the prevalence of gametocytaemia before antimalarial treatment and monitored clearance of gametocytes after treatment in asymptomatic malaria children.

Methods

A total of 274 primary school children were screened for P. falciparum parasitaemia by microscopy. One hundred and fifty-five (155) parasite positive children were treated under direct observation with dihydroartemisinin-piperaquine (DP). Gametocyte carriage was determined by microscopy seven days prior to treatment, day 0 before treatment, and on days 7, 14 and 21 post initiation of treatment.

Results

The prevalence of microscopically-detectable gametocytes at screening (day −7) and enrolment (day 0) were 9% (25/274) and 13.6% (21/155) respectively. Following DP treatment, gametocyte carriage dropped to 4% (6/135), 3% (5/135) and 6% (10/151) on days 7, 14 and 21 respectively. Asexual parasites persisted in a minority of treated children, resulting in microscopically detectable parasites on days 7 (9%, 12/135), 14 (4%, 5/135) and 21 (7%, 10/151). Gametocyte carriage was inversely correlated with the age of the participants (p = 0.05) and asexual parasite density (p = 0.08). In a variate analysis, persistent gametocytaemia 7 or more days after treatment was significantly associated with post-treatment asexual parasitaemia at day 7 (P = 0.027) and presence of gametocytes on the day of treatment (P < 0.001).

Conclusions

Though DP provides both excellent cure rates for clinical malaria and a long prophylactic half-life, our findings suggest that after treatment of asymptomatic infections, both asexual parasites and gametocytes may persist in a minority of individuals during the first 3 weeks after treatment. This indicates DP may be unsuitable for use in mass drug administration strategies towards malaria elimination in Africa.

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双氢青蒿素-哌喹治疗前后无症状学龄儿童恶性疟原虫配子细胞血症的流行情况

背景:在大多数疟疾流行地区，无症状疟原虫携带者占疟疾感染者的大多数。这些无症状感染者中有一部分携带配子体，这是疟疾寄生虫的传播阶段，可维持人与蚊子之间的传播。很少有研究在无症状的学龄儿童中检查配子细胞血症，这些儿童可能形成重要的传播库。我们评估了抗疟疾治疗前配子细胞血症的流行情况，并监测了治疗后无症状疟疾儿童配子细胞的清除情况。方法对274名小学生进行恶性疟原虫镜检。155例寄生虫阳性患儿采用双氢青蒿素-哌喹(DP)直接观察治疗。在给药前7天、给药前0天、给药后7天、14天和21天用显微镜检测配子体携带情况。结果筛选(第7天)和入组(第0天)配子体显微镜检出率分别为9%(25/274)和13.6%(21/155)。DP处理后，配子体携带率在第7、14和21天分别下降到4%(6/135)、3%(5/135)和6%(10/151)。少数接受治疗的儿童存在无性寄生虫，在第7天(9%，12/135)、第14天(4%，5/135)和第21天(7%，10/151)显微镜下可检出寄生虫。配子体携带量与受试者年龄呈负相关(p = 0.05)，与无性寄生虫密度呈负相关(p = 0.08)。在一项变量分析中，治疗后7天或更长时间持续的配子细胞血症与治疗后第7天的无性寄生虫血症(P = 0.027)和治疗当天配子细胞的存在显著相关(P <0.001)。结论虽然DP对临床疟疾具有良好的治愈率和较长的预防半衰期，但我们的研究结果表明，在治疗无症状感染后，少数个体在治疗后的前3周内可能存在无性寄生虫和配子细胞。这表明DP可能不适合用于非洲消除疟疾的大规模药物管理战略。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Parasite Epidemiology and Control Medicine-Infectious Diseases

CiteScore

5.70

自引率

3.10%

发文量

审稿时长

17 weeks

期刊介绍： Parasite Epidemiology and Control is an Open Access journal. There is an increasing amount of research in the parasitology area that analyses the patterns, causes, and effects of health and disease conditions in defined populations. This epidemiology of parasite infectious diseases is predominantly studied in human populations but also spans other major hosts of parasitic infections and as such this journal will have a broad remit. We will focus on the major areas of epidemiological study including disease etiology, disease surveillance, drug resistance and geographical spread and screening, biomonitoring, and comparisons of treatment effects in clinical trials for both human and other animals. We will also look at the epidemiology and control of vector insects. The journal will also cover the use of geographic information systems (Epi-GIS) for epidemiological surveillance which is a rapidly growing area of research in infectious diseases. Molecular epidemiological approaches are also particularly encouraged.