Mutengo Mable, Kaduková Michaela, Mulunda Namwiinga R, Chabala Freeman W, Dashti Alejandro, Hayashida Kyoko, Chinyanta Stanley, Chisanga Kelly, Castro Lourdes, Sánchez Sergio, Mwansa James, Köster Pamela C, González-Barrio David, Maloney Jenny G, Santín Mónica, Sotillo Javier, Carmena David
Institute of Basic and Biomedical Sciences, Levy Mwanawasa Medical University, Lusaka, Zambia.
Department of Pathology and Microbiology, University Teaching Hospitals, Lusaka, Zambia.
PLoS Negl Trop Dis. 2024 Dec 13;18(12):e0012717. doi: 10.1371/journal.pntd.0012717. eCollection 2024 Dec.
PCR-based screenings on the presence of diarrhoea-causing intestinal protist species are limited in Zambia, resulting in inaccurate current prevalence and epidemiological data. Sensitive PCR-based methods are particularly well suited for detecting subclinical infections in apparently healthy carriers.
In this prospective cross-sectional study, we investigated the occurrence of the most common intestinal protists in an apparently healthy paediatric population (5-18 years) in Lusaka Province, Zambia. We collected single stool samples (n = 256) and epidemiological questionnaires on demographics, behavioural habits, drinking water and toilet access from participating children. We used PCR for the initial screening of samples for the presence of intestinal protist species and Sanger and next-generation sequencing for genotyping. We conducted statistical analyses to assess the association of the gathered variables with an increased likelihood of the investigated pathogens.
Blastocystis sp. was the most prevalent intestinal protist found (37.9%, 97/256; 95% CI: 31.9-44.1), followed by Giardia duodenalis (30.9%, 79/256; 95% CI: 25.3-36.90), Entamoeba dispar (13.3%, 34/256; 95% CI: 9.4-18.1), and Cryptosporidium spp. (4.3%, 11/256, 95% CI: 2.2-7.6). Entamoeba histolytica was not detected. Based on Sanger sequencing results, subtypes ST2 (44.3%, 43/97), ST1 (35.1%, 34/97), and ST3 (20.6%, 20/97) were identified within Blastocystis sp. and assemblages B (71.0%), A+B (16.1%), and A (12.9%) within G. duodenalis. Cryptosporidium parvum (81.8%) and C. hominis (18.2%) were the only two Cryptosporidium species found. Living in the Kafue District was positively associated with higher infection rates by G. duodenalis and Blastocystis sp. Schoolchildren living in Chongwe District were more likely to be infected by Cryptosporidium spp.
CONCLUSIONS/SIGNIFICANCE: Intestinal protist infection/colonization is a common finding in apparently healthy children in Lusaka Province, Zambia. Asymptomatic carriers may play an underestimated role as spreaders of gastrointestinal parasitic infections. This study improves our current understanding of the epidemiology of diarrhoea-causing protists in Zambia and sub-Saharan Africa and indicates that the role of asymptomatic carriers of gastrointestinal parasites in transmission should be further explored.
在赞比亚，基于聚合酶链反应（PCR）对致腹泻肠道原生生物物种存在情况的筛查有限，导致当前患病率和流行病学数据不准确。基于PCR的灵敏方法特别适合检测看似健康的携带者中的亚临床感染。
在这项前瞻性横断面研究中，我们调查了赞比亚卢萨卡省看似健康的儿童群体（5 - 18岁）中最常见的肠道原生生物的发生情况。我们收集了单个粪便样本（n = 256）以及参与研究的儿童关于人口统计学、行为习惯、饮用水和厕所使用情况的流行病学调查问卷。我们使用PCR对样本进行肠道原生生物物种存在情况的初步筛查，并使用桑格测序和下一代测序进行基因分型。我们进行了统计分析，以评估所收集变量与被调查病原体感染可能性增加之间的关联。
芽囊原虫属是最常见的肠道原生生物（37.9%，97/256；95%置信区间：31.9 - 44.1），其次是十二指肠贾第虫（30.9%，79/256；95%置信区间：25.3 - 36.90）、溶组织内阿米巴（13.3%，34/256；95%置信区间：9.4 - 18.1）和隐孢子虫属（4.3%，11/256，95%置信区间：2.2 - 7.6）。未检测到溶组织内阿米巴。基于桑格测序结果，在芽囊原虫属中鉴定出亚型ST2（44.3%，43/97）、ST1（35.1%，34/97）和ST3（20.6%，20/97），在十二指肠贾第虫中鉴定出组合B（71.0%）、A + B（16.1%）和A（12.9%）。微小隐孢子虫（81.8%）和人隐孢子虫（18.2%）是仅发现的两种隐孢子虫物种。生活在卡富埃区与十二指肠贾第虫和芽囊原虫属的较高感染率呈正相关。生活在琼圭区的学童更有可能感染隐孢子虫属。
结论/意义：肠道原生生物感染/定植在赞比亚卢萨卡省看似健康的儿童中是常见现象。无症状携带者作为胃肠道寄生虫感染传播者的作用可能被低估。本研究增进了我们目前对赞比亚和撒哈拉以南非洲致腹泻原生生物流行病学的理解，并表明应进一步探索胃肠道寄生虫无症状携带者在传播中的作用。
