Prevalence and Determinant Factors of Intestinal Parasitic Infections and Undernutrition among Primary School Children in North-Central Ethiopia: A School-Based Cross-Sectional Study

**Background:** Intestinal parasitic infections (IPIs) and undernutrition are major public health problems in developing countries, particularly among school children, where they impair cognitive development, academic performance, and physical growth. Ethiopia bears a high burden of both conditions, but comprehensive local data from North-central Ethiopia were lacking. This study aimed to determine the prevalence and determinant factors of IPIs and undernutrition among primary school children in Dessie town.

**Methods:** A school-based cross-sectional study was conducted from February to March 2021 among 450 children (grades 1–8) selected via stratified random sampling from four government primary schools in Dessie town, North-central Ethiopia. Data on sociodemographics, hygiene practices, and nutrition were collected using pretested structured questionnaires administered to students and parents/guardians. Stool samples were collected up to three times at 24-hour intervals and examined using direct saline wet mount and formalin-ether concentration techniques. Height and weight were measured, and BMI was calculated. Nutritional status (underweight, stunting, wasting) was assessed using WHO AnthroPlus software based on z-scores < -2SD. Data were analyzed using SPSS version 26; binary logistic regression was used with P<0.05 considered significant.

**Key Results:** The overall prevalence of IPIs was 28.9% (130/450). Intestinal protozoa were detected in 19.1% and helminths in 9.8%. The most common parasites were Entamoeba histolytica/dispar (9.3%), Giardia intestinalis (7.6%), Enterobius vermicularis (2.9%), and Ascaris lumbricoides (2.7%). IPI prevalence was higher in males (16.5%) than females (12.4%). Factors significantly associated with IPIs included age 6–11 years (AOR=2.96; 95% CI: 1.19–7.4; P=0.02), maternal illiteracy (AOR=3.32; 95% CI: 1.43–7.71), eating raw/undercooked fruits and vegetables (AOR=4.02; 95% CI: 2.28–8.44), open field defecation (AOR=4.39; 95% CI: 2.28–8.44), untrimmed/dirty fingernails (AOR=2.45; 95% CI: 1.42–4.23), not washing hands after toilet (AOR=3.58; 95% CI: 1.64–7.82), and sickness in the past week (AOR=4.44; 95% CI: 2.61–7.55). The prevalence of underweight, stunting, and wasting was 22.4%, 26.2%, and 20.7%, respectively. IPIs were significantly associated with underweight (AOR=3.21; 95% CI: 1.81–6.21), stunting (AOR=3.75; 95% CI: 2.03–6.21), and wasting (AOR=3.61; 95% CI: 2.21–6.21). Male sex, larger family size (>8 members), lower meal frequency, and skipping breakfast were also significant predictors of undernutrition.

**Clinical Implications:** This study confirms that IPIs and undernutrition remain major health problems among school children in North-central Ethiopia, with over a quarter of children infected with intestinal parasites and more than one in five affected by each form of undernutrition. The strong association between IPIs and all three forms of undernutrition suggests a bidirectional relationship where parasites impair nutrient absorption and malnutrition weakens immune defenses. The findings highlight the need for integrated interventions including periodic deworming, improved water/sanitation/hygiene (WASH) infrastructure, maternal education, school feeding programs, and health education targeting children and families. The study provides baseline data for monitoring progress and designing targeted public health strategies in the region.