Objective: Describe the incidence of parasitosis and its genotyping, dependent on socio-environmental factors as determinants of health in children from Tlaxcoapan, Hidalgo. Material and methods: An observational, descriptive, cross-sectional epidemiological study was conducted on 186 children under 5 years of age from the municipality of Tlaxcoapan, with parental consent. Stool samples were collected for a three-series coproparasitological examination through fresh slides, Faust, and Ziehl-Neelsen staining techniques. Socio-environmental factors and symptomatology were assessed through interviews. The cysts from samples that tested positive for Giardia intestinalis (G. intestinalis) were subjected to semi-nested PCR (polymerase chain reaction) of the glutamate dehydrogenase gene. Statistical analysis was performed using SPSS-24. Results: Out of 186 children, 46 (25%) tested positive for parasitic and/or commensal microorganisms in their coproparasitological examination, while 140 (75%) were uninfected. The method with the greatest specificity was the direct (66% positive diagnoses), followed by the Faust method (34%). Ziehl-Neelsen staining showed negative results for Microsporidium, Cryptosporidium and Cyclospora. Genotyping of G. intestinalis denotes two genotypes: AI, characteristic of animals and humans, and AII, primarily observed in humans. Conclusions: Parasitic infection affected 25% of the children studied. The socio-environmental factors with the highest risk were the lack of water purification and high coexistence with domestic animals. Genotyping of G. intestinalis revealed two genotypes, AI and AII. The AI genotype has zoonotic potential, highlighting its importance in public health.
