Field observations on the longevity of Trichuris suis ova.
D000818:Animals; D004739:England; D005243:Feces / Q000469:parasitology; D012987:Soil; D013552:Swine; D013553:Swine Diseases / Q000469:parasitology*; D014257:Trichuriasis / Q000469:parasitology / Q000662:veterinary*; D014258:Trichuris / Q000254:growth & development*
D012987:Soil