Unveiling the Role of Intestinal Parasitic Infections in Childhood Malnutrition in Assiut Governorate.

Intestinal parasitic infections (IPIs) are highly prevalent worldwide, particularly among children living in lowresource settings. (1) These infections pose a significant public health challenge due to their widespread distribution and their impact on vulnerable populations, especially preschool and school-aged children. (2) Common intestinal parasites include protozoa such as Giardia lamblia and Entamoeba histolytica, as well as helminths like Ascaris lumbricoides, Trichuris trichiura, and hookworms.(3) IPIs contribute to a range of health problems in children, including diarrhea, anemia, general weakness, and impaired physical development. These infections often cause malabsorption of nutrients and chronic blood loss, which can severely affect children's growth and overall health status. (2) Malnutrition has been defined by the World Health Organization as a major global health challenge with significant implications for morbidity and mortality worldwide.(4) It is characterized by conditions such as stunting, wasting, and underweight, all of which reflect inadequate nutrition and impaired growth. . (Yoseph \& Beyene, 2020).Malnutrition is influenced by multiple interconnected factors including socioeconomic status, inadequate feeding practices, lack of exclusive breastfeeding, recurrent infections, limited healthcare access, and poor environmental conditions such as unsafe water and sanitation. (5) Persistent and/or recurring IPIs are considered important contributors to adverse developmental outcomes depending on parasite species and infection dynamics.(6) They may contribute to malnutrition through both direct and indirect mechanisms. Directly, they can induce chronic subclinical systemic inflammation and modulate the host immune response to ensure persistence, resulting in adverse effects on growth.(7) For example, infection with Cryptosporidium spp.

has been linked to reduced length-for-age, mediated by increased systemic inflammation and decreased circulating IGF-1 concentrations.(8) Indirectly, they may promote environmental enteric dysfunction (EED), which is subclinical disorder of the small intestine that can contribute to malnutrition. It involves villous atrophy and crypt hyperplasia, reducing nutrient absorption, and infections such as G. lamblia may play a key role in its development.(6) Additionally IPIs may interact with the normal gut microbiota, with each influencing the other's pathogenic potential, and this interaction can contribute to malnutrition.(7) IPIs can reduce food intake by causing illness, abdominal discomfort, or altering appetite regulation.(8) They may affect neuroendocrine signals, modifying taste perception and satiety hormones, such as elevated leptin levels observed in children infected with E. histolytica, Strongyloides spp., and G. lamblia. Infections like Trichuris trichiura have also been linked to lower intake of protein, energy, iron and riboflavin.(6) While parasites like hookworm directly cause nutrient loss through blood and iron depletion, often resulting in anaemia. (1) Deficiencies in zinc, vitamin D and omega-3 fatty acids are common in children affected by malnutrition and parasitic infections. Zinc and vitamin D is essential for gut integrity, immune function, and growth, while omega-3 fatty acids support intestinal structure and have anti-inflammatory effects. Low levels of these nutrients may worsen intestinal dysfunction, including EED, and contribute to impaired growth.(9) In the light of the previously discussed mechanisms, a strong bidirectional relationship exists between parasitic infections and malnutrition, whereby each condition aggravates the other, forming a vicious cycle that increases the risk of stunting, poor growth, anaemia, and impaired immune function.(3)