HelminthiasisHelminthiasis, AnimalHelminthsNeglected DiseasesAscaris lumbricoidesAnthelminticsTrichurisAscariasisAncylostomatoideaMagicTrichuriasisSierra LeoneSoilIntestinal Diseases, ParasiticToilet FacilitiesHookworm InfectionsStrongyloides stercoralisDuddingtoniaNecator americanusSchistosomiasisCentral Nervous System HelminthiasisAncylostomaAlbendazolePraziquantelFecesParasite Egg CountHygienePrevalenceKiller Cells, NaturalNigeriaCross-Sectional Studies