15 letters · 22 points in Scrabble
noun an infestation with or a resulting infection caused by a parasite of the genus Schistosoma; common in the tropics and Far East; symptoms depend on the part of the body infected
originFrom schistosome + -iasis. From scientific name Schistosoma + Ancient Greek -σις (-sis, nouns of action).
Etymology from Wiktionary, CC BY-SA 3.0