The reluctant schoolboy and the persistent bellyache.
D000005:Abdomen; D000293:Adolescent; D001835:Body Weight; D005872:Giardia; D005873:Giardiasis / Q000175:diagnosis* / Q000503:physiopathology; D006801:Humans; D008297:Male; D009325:Nausea / Q000209:etiology; D010146:Pain / Q000209:etiology