Impact of Malnutrition on the Course of Helminth Infection and the Associated Immune Response

Abstract Malnutrition and helminth infections are known to be associated conditions. Malnutrition, which refers to excesses, deficiencies, or imbalances in intake of energy and/or nutrients, affects millions of people worldwide and is the most common cause of immunodeficiency in the world. In helminth-infected individuals, malnutrition has been associated with an augmented morbidity rate, a higher parasitic load, and prolonged infections, and may also contribute to increased mortality. Helminth infections affect millions of people worldwide, particularly in non-industrialized countries, leading to chronic infections. This review focuses on the bidirectional relationships between macronutrient malnutrition and helminth infections. Relevant scientific articles published until May 2024 were retrieved from PubMed and Google Scholar. The data extracted were parameters of immunology, hematology, parasitology, disease, and nutrition. Malnutrition leads to alterations in the immune responses to helminth infections, including innate responses (Heligmosomoides polygyrus, hookworms, Trichinella spp., Trichuris spp.), T-cell–mediated responses (Ascaris spp., H. polygyrus, Trichuris spp.), and antibody responses (Ascaris spp., H. polygyrus, Schistosoma spp., Trichinella spp., Trichuris spp.), frequently resulting in increased parasite load and worm fecundity. However, in some cases malnutrition may have negative effects on the life cycle of helminths, including reductions in worm weight, egg production, worm size, and parasite fecundity. Malnutrition has a notorious influence on both host and parasite. The consequences for the host would be related to the severity and type of malnutrition condition, and the helminth involved.