Ascaris infection and macronutrients: targeting the dynamic interactions between parasite, gut microbes and immune responses by dietary and community-based interventions

• Applicants: Professorin Dr. Susanne Hartmann; Dr. Sebastian Rausch; Professor Dr. Jürgen Zentek
• Subject Area: Parasitology and Biology of Tropical Infectious Disease Pathogens
• Term: since 2025
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 501641046

Infections with the roundworm Ascaris, account for the majority of parasitic worm infections with a quarter of the world’s population at risk of infection. Children are particularly vulnerable to Ascaris infections and are often afflicted by multiple coinfections. Moreover, Ascaris co-exist with undernutrition in children living in poverty. Both helminth infections and malnutrition are associated with reduced physical and cognitive development and are often accompanied by micronutrient deficiencies (iron, zinc, vitamin A). However, micronutrient supplementation resulted in rather limited effects and studies on the effects of macronutrient supplementation (protein, dietary fibre) are scarce. In contrast, our preliminary data from pigs experimentally infected with Ascaris suum clearly show that the supplementation of dietary fibres result in stronger Th2 immune responses and impaired parasite development. Furthermore, protein malnourishment was shown to compromise anti-nematode immune responses in several experimental nematode infection models and our preliminary field study performed in an Ascaris endemicity region in western Kenya showed that children had limited access to dietary protein. Therefore, the proposed project aims to determine the health benefits of a combined protein- fibre supplementation in school-going children in an Ascaris endemic region in Kenya. Nutritional bars with a high content of protein/fibre will be provided daily during 4 intervention phases, each covering 4 weeks and followed by 3 intervention-free months. Hence, the influence on the child’s health, infection status and immune reactivity will be disaggregated over a period of 16 months. As our earlier work showed that Ascaris infection alters the composition of the gut microbiota, we will further investigate the impact of the diet on the Ascaris-microbe interactions. Ascaris infections represent a high socioeconomic burden in communities living in poverty. By capturing the sociocultural aspect and targeting education on the links between diet, gut health, and worm infections, our project integrates social and behavioural change communication to achieve sustainable control of STH infections via a community participating approach. Ascaris infections are also highly prevalent in pigs, offering an excellent model that enables to study the impact of dietary interventions and the mechanisms underlying the interactions between parasite, immune responses and gut microbes at the site of infection. Thus, the key goals of our study are to evaluate the benefits of high protein and dietary fibre supplementation in school children in terms of (i) Ascaris infection rates and intensity, (ii) anti-parasite immune responses, iii) composition and metabolic profile of the gut microbiome and (iv) community nutritional behaviour. In parallel, the pig will be used as a model to study the underlying mechanisms directly at the site of infection.

• DFG Programme: Research Grants
• International Connection: Kenya
• International Co-Applicants: Doris Njomo, Ph.D.; Dr. Maurice Odiere