Protozoan InfectionsIntestinal Diseases, ParasiticHelminthsHelminthiasisGiardia lambliaYemenPrevalenceAmoebozoaEntamoeba histolyticaEntamoebiasisGiardiasisFecesEukaryotaCryptosporidiosisProtozoan Infections, AnimalProtozoan ProteinsDNA, ProtozoanCiliophoraGenes, ProtozoanRNA, ProtozoanGenome, ProtozoanCross-Sectional Studies