Gastrointestinal disorders due to parasites – a narrative review of the literature

Abstrakt

Intestinal parasites constitute a significant public health problem, particularly in developing countries. It is estimated that over 1.5 bln people worldwide are infected with intestinal parasites. These pathogens fall into 2 main groups: protozoa (e.g., Giardia duodenalis, Entamoeba histolytica, Cryptosporidium) and helminths – multicellular worms, which include roundworms (e.g., roundworm, pinworm, hookworm), tapeworms (Taenia spp., Diphyllobothrium latum), and flukes (Schistosoma spp.).
Parasites cause illnesses with diverse clinical presentations, ranging from asymptomatic carriage to acute and chronic diarrhea, abdominal pain, malnutrition, and anemia. Some, such as E. histolytica, lead to invasive amoebiasis, while T. solium leads to neurocysticercosis, which contributes to epilepsy. Others, such as Giardia, disrupt intestinal absorption, leading to wasting, especially in children.
Diagnosis is primarily based on stool examination (microscopy, antigen testing, PCR). Treatment depends on the parasite – metronidazole, albendazole, praziquantel, and ivermectin are used, among others. Increasing attention is being paid to supporting treatment with probiotics and zinc supplementation, which improve therapeutic outcomes, especially in protozoal infections.
The pathogenesis of infections includes mechanical intestinal damage, bleeding, nutrient utilization by parasites, and the induction of inflammatory responses and microbiome dysbiosis. Parasites lead to serious health consequences, particularly in children (deficiencies, impaired growth and development).
Prevention relies on improved sanitation, access to clean water, health education, cooking meat, mass deworming in endemic areas, and basic personal hygiene. Effective vaccines do not exist, although research is ongoing.