Biomarker Profiling of Calprotectin and Lactoferrin in Children Under Five years with Protozoal Intestinal Infections in Kirkuk

Abstract Background & Aim: Intestinal protozoal infections are prevalent intestinal infection and common infectious disease causing many health problems and impaired growth and physical development. So, the present investigation was aimed to evaluate some inflammatory biomarkers among children under 5 years of age infected with intestinal protozoal infection. Materials and Methods: A 260 children under 5 years of age whom attended a governmental hospital were included in the study, after receiving an agreement from their parents before starting the study. Across sectional study was done on 260 children from period starting from 1/9/2024 till end of 1/2/2025 in Kirkuk city Iraq. Results: The results showed that the number of positive samples for parasitological detection assays was 160 samples, while the number of negative samples was 100 samples. The findings showed a relationship between age and the type of parasite, as it was found that the highest infections were with the E. histolytica parasite, especially in the age group (4-5) years, which showed significant (P≤0.05) differences with the rest of the parasite types in the different age groups. While regarding gender, there was no significant difference in the proportion of each parasite between males and females. Regarding residency, a significant (P≤0.05) difference was found (51.25%), with the most cases being rural disease, and the most prevalent parasite was E. histolytica, accounting for 51.25% of the total cases. The same was observed with respect to the type of water consumed, with the highest incidence of intestinal protozoal infection especially E. histolytica and C.parvum being found among patients who consumed tap water. A similar pattern was evident in relation to the type of nutrition, with the highest incidence of E. histolytica in the bulky food group. Finally, regarding hospitalization, the highest incidence was E. histolytica, which reached 35%, which showed significant (P≤0.05) differences for the rest of the detected parasite species. Among all single infections of intestinal protozoa, E. histolytica showed the highest calprotectin levels (6.7130 ± 2.91 ng/ml) and elevated morphonuclear (6.06 ± 3.0 cells/μL) and lymphocyte counts (4.3 ± 2.0), with reduced Hb (11.0 ± 1.6 g/dL). C. parvum showed lower levels of calprotectin (4.34 ± 1.31) but relatively high lactoferrin levels (4.68 ± 2.62) and reduced morphonuclear and lymphocyte counts. For Giardia lamblia infections presented the lowest inflammatory biomarker levels, especially calprotectin (4.38 ± 1.21) and lactoferrin (3.63 ± 0.91), showed that 112 patients with fever, 52 with bloody diarrhea, and 64 with dehydration had a positive calprotecrtin result, while 110 patients with fever, 44 with bloody diarrhea, and 70 with dehydration had a positive lactoferrin result. The patients with positive results for the fecal occult blood test showed significant differences (p<0.05) compared to those who showed negative results for the fecal occult blood test. Conclusion: This comparative analysis underscores the diagnostic utility of fecal biomarkers in children under 5 years the intestinal protozoal infections and highlights the distinct inflammatory profiles elicited by different protozoa. Future research should focus on integrating these biomarkers into routine screening to enhance early detection and optimize treatment approaches, especially in endemic areas.