Asymptomatic carriage of intestinal protists is common in children in Lusaka Province, Zambia

Authors: MUTENGO, MABLE - Levy Mwanawasa Medical University; KADUKOVA, MICHAELA - Health Research Institute Of The San Carlos Clinical Hospital; MULUNDA, NAMWIINGA - Levy Mwanawasa Medical University; DASHTI, ALEJANDRO - Health Research Institute Of The San Carlos Clinical Hospital; HAYASHIDA, KYOKO - Hokkaido University; CHINYANTA, STANLEY - Levy Mwanawasa Medical University; CHISANGA, KELLY - Levy Mwanawasa Medical University; CASTRO, LOURDES - Health Research Institute Of The San Carlos Clinical Hospital; SANCHEZ, SERGIO - Health Research Institute Of The San Carlos Clinical Hospital; MWANSA, JAMES - Levy Mwanawasa Medical University; KOSTER, PAMELA - Health Research Institute Of The San Carlos Clinical Hospital; GONZALEZ-BARRIO, DAVID - Health Research Institute Of The San Carlos Clinical Hospital; Maloney, Jenny; Santin, Monica

Submitted to: PLOS Neglected Tropical Diseases
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/21/2024
Publication Date: 12/13/2024
Citation: Mutengo, M., Kadukova, M., Mulunda, N.R., Dashti, A., Hayashida, K., Chinyanta, S., Chisanga, K., Castro, L., Sanchez, S., Mwansa, J., Koster, P.C., Gonzalez-Barrio, D., Maloney, J.G., Santin, M. 2024. Asymptomatic carriage of intestinal protists is common in children in Lusaka Province, Zambia. PLOS Neglected Tropical Diseases. 18(12): e0012717. https://doi.org/10.1371/journal.pntd.0012717.
DOI: https://doi.org/10.1371/journal.pntd.0012717

Interpretive Summary: Diarrhoea-causing intestinal protist are a major public health concern in sub-Saharan countries with limited access to safe drinking water and with poor sanitation infrastructures. Children are at higher risk of infection because of suboptimal personal hygiene practices and immature immune systems. Presence of intestinal protist was a common finding in apparently healthy children in Lusaka Province (Zambia) examined in this study and indicates that the role of asymptomatic carriers of gastrointestinal parasites in transmission should be further explored. This study improves our current understanding of the epidemiology of diarrhoea-causing protists in Zambia and sub-Saharan Africa. This information will be useful to other scientists, medical professionals, veterinarians, and public health agencies to better understand transmission, zoonotic potential, and public health importance of diarrhoea-causing intestinal protists.

Technical Abstract: Background 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. Methodology 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 and potential risk factors from participating children. We used PCR for the initial screening of samples for the presence of intestinal protest species and Sanger and next-generation sequencing for genotyping. We conducted statistical analyses to assess the association of potential risk factors with the presence of the investigated pathogens. Principal Findings 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. Belonging to the 10–14 years age group was a risk factor for G. duodenalis and Cryptosporidium spp. infections. 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.