Household deprivation score demonstrates graded association with intestinal parasitic infections among schoolchildren in a conflict-affected setting: a cross-sectional study.

BACKGROUND

Intestinal parasitic infections (IPIs) remain highly prevalent in conflict-affected settings where water, sanitation, and health systems are disrupted. Simple, scalable tools for identifying high-risk populations are urgently needed.

METHODS

We conducted a cross-sectional study of 1,200 schoolchildren aged 5-15 years across nine districts in Al-Dhalea Governorate, Yemen (April-October 2025). Stool samples were analyzed using direct microscopy and formalin-ether concentration. A novel Household Deprivation Score (HDS; range 0-3) was constructed from three indicators of socioeconomic and spatial disadvantage. Multilevel mixed-effects logistic regression was used to assess statistical associations with IPI positivity. All associations are correlational; causal inference is precluded by the cross-sectional design.

RESULTS

Overall, the IPI prevalence was 46.2% (95% CI: 43.4 to 49.0%). The Entamoeba histolytica dispar complex was the most frequently detected (38.6%), but sensitivity analyses suggest that 70 to 80% may be non-pathogenic E. dispar. The HDS showed modest screening performance (AUC = 0.63; sensitivity: 67.2%, specificity: 61.4%) with a strong graded association with IPI positivity: compared with HDS = 0, adjusted odds ratios increased from 1.45 (95% CI: 1.08 to 1.95) for HDS = 1 to 2.89 (95% CI: 2.01 to 4.15) for HDS = 3 (p for trend less than 0.001). Additional factors statistically associated with IPI included anemia (AOR = 2.35), animals in the home (AOR = 1.89), irregular nail trimming (AOR = 1.82), and always washing hands before eating (compared to rarely), which was associated with 37% lower odds of IPI (AOR = 0.63, 95% CI: 0.45 to 0.87).

INTERPRETATION: The HDS showed a graded association with IPI prevalence (AUC = 0.63), indicating modest discriminative ability suitable for risk stratification rather than diagnosis. Species-stratified analyses excluding Entamoeba cases (29.4% of positives) attenuated the HDS-pathogen association, with the AOR for HDS = 3 decreasing from 2.95 to 2.18 and HDS = 1 losing significance. These findings suggest partial influence of non-pathogenic carriage. The HDS may support resource allocation but should not replace diagnostic testing. Molecular confirmation (PCR) and external validation in other conflict-affected settings are needed before broader implementation.