crotch rot

村上春樹の "Hear The Wind Sing" を読み始めました。
I came across a copy of Hartfield’s long-out-of-print first book during my last summer vacation of junior high, a time marked in my memory by a terrible case of crotch rot. The uncle who gave me the book died in agony three years later of intestinal cancer. The last time I saw him, the doctors had hacked him up so badly that he bristled with plastic tubes ferrying fluids in and out of both ends of his body. He was shrunken and his skin had turned reddish brown, so that he resembled a crafty old monkey.
小説というより随筆の様な文章です。ところで "crotch rot" とはかなり恐ろしい病気に思えますが実際はどうでしょうか？　辞書を見ます。
医学辞書によると "crotch rot" は医学用語では "tinea cru´ris" にあたる様だ。
・Miller-Keane Encyclopedia and Dictionary of Medicine, Nursing, and Allied Health: tinea cru´ris: ringworm of the groin area, starting in the perineal folds and extending onto the inner surface of the thighs; it is more common in males and is caused by Epidermophyton floccosum or species of Trichophyton; called also eczema marginatum, epidermophytosis cruris, and jock itch.
スラングでは性病の意味で使うこともある様だが、中三の少年なのでこの意味ではないでしょう。
・A Dictinary of Slang: General term for a sexual infection of the genitals, or venereal disease.
いわゆる「いんきんたむし」の事でしょうね。