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. 2025 Oct 9;19(10):e0013167.
doi: 10.1371/journal.pntd.0013167. eCollection 2025 Oct.

The associations between Schistosoma mansoni infection, pre-treatment symptoms, praziquantel side effects, and treatment efficacy in Ugandan school-aged children

Huanghehui Yu  1   2 , Moses Arinaitwe  1   3 , Adriko Moses  3 , Narcis Kabatereine  3 , Edridah M Tukahebwa  3 , David W Oguttu  3 , Aidah Wamboko  3 , Annet Namukuta  3 , Annet Enzaru  3 , Joaquin M Prada  4 , Alan Fenwick  5 , Joanne P Webster  5   6 , Poppy H L Lamberton  1   5 , Jessica Clark  1
Affiliations

The associations between Schistosoma mansoni infection, pre-treatment symptoms, praziquantel side effects, and treatment efficacy in Ugandan school-aged children

Huanghehui Yu et al. PLoS Negl Trop Dis. .

Abstract

Background: Over 240 million people have schistosomiasis. Mass drug administration (MDA) with the anthelmintic praziquantel is the cornerstone of control. Treatment side effects are commonly observed and may be associated with dying worms. Side effects have also been reported as a reason for reduced MDA uptake, potentially resulting in those most in need refusing repeated treatment. An improved understanding of the association between side effects and infection intensity, pre-treatment health, and drug efficacy, may help inform education campaigns to facilitate increased MDA uptake.

Methods: Using latent class analyses, Beta regression, and dose response curves, we analysed egg and antigen parasitological data alongside health and side-effects survey data pre- and post-praziquantel-treatment from two primary schools (Bugoto Lake View (LV) and Musubi Church of God (CoG)) in Schistosoma mansoni high endemicity Ugandan villages to understand whether pre-treatment infection status or intensity were related to 1) pre-treatment symptoms, 2) post-treatment side effects, and 3) whether parasite clearance after treatment was associated with side effects.

Principal findings: At Bugoto LV: Abdominal pain, blood-in-stool, and itching/rash symptoms were non-linearly associated with infection intensity; Diarrhoea, headache and vomiting side effects were non-linearly associated with infection intensity. At Musubi CoG: Blood-in-stool, headache, and pain-when-urinating symptoms were non-linearly associated with infection intensity; Abdominal pain, diarrhoea, and vomiting side effects were non-linearly associated with infection intensity. There was no relationship between infection status (infected/ uninfected) and symptoms or side effects at either school. No association was found between infection clearance and the presence of side effects at either school.

Conclusions: We show no evidence that being infected predisposes someone to side effects, nor that side effects are related to treatment efficacy. Relationships between pre-treatment infection intensity and pre-treatment symptoms or post-treatment side effects varied by school suggesting unmeasured factors such as co-infections or other health conditions could impact symptom and side effect reporting.

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Conflict of interest statement

The authors have declared that no competing interests exist.

Figures

Fig 1
Fig 1. The Schistosoma mansoni infection probability (from the latent class analysis) of every participant in Bugoto Lake View (LV) (top graph) and Musubi Church of God (CoG) (bottom graph) primary schools who reported (orange), or did not report (blue) pre-treatment symptoms (x-axis).
Note the jittering of points to prevent them overlaying one another.
Fig 2
Fig 2. Schistosoma mansoni infection intensity dose response curves (from the latent class analysis) for the corresponding pre-treatment symptoms and post-treatment side effects of Schistosoma mansoni infection, including abdominal pain, blood-in-stool, diarrhoea, headache, itching and rash, nausea, and pain-when-urinating, for participants from Bugoto Lake View (LV) and Musubi Church of God (CoG) primary schools.
Fig 3
Fig 3. The Schistosoma mansoni infection probability (from the latent class analysis) of every participant in Bugoto Lake View (LV) (top graph) and Musubi Church of God (CoG) (bottom graph) primary schools who reported (orange), or did not report (blue), post-treatment side effects (x-axis).
Note the jittering of points to prevent them overlaying one another.
Fig 4
Fig 4. The clearance probability from the latent class analysis compared with not reporting (left – NO) or reporting (right – YES) abdominal pain, diarrhoea, headache, or vomiting as side effects after praziquantel treatment in Bugoto Lake View (LV) (dark blue) and Musubi Church of God (CoG) (green) primary schools.
The size of dots relates to the number of participants.
See this image and copyright information in PMC

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