Jordan at Macvaysia has been wondering whether the English word cooties, which he defines as “an imaginary affliction, used by kids in the west as an excuse for shunning and/or teasing other kids,” might come from Malay kudis ‘scabies’ (Indonesian Wikipedia) rather than, as dictionary etymologies suggest, Malay kutu ‘louse.’ I have no idea whether this is plausible, but I figure someone out there might.
Update (July 2009). It looks as if the true etymology is less exotic; it’s simply an extension of coot (there was a proverbial phrase “as lousy as a coot”). See these American Dialect Society listserv postings: 1, 2, 3, 4; Jonathan Lighter’s summary from the last:
What I think happened:
“lousy as a coot” > “cooty” (adj.) = “lousy, as is a coot” > “coot”
(back-formation) and “cootie” (through mishearing and in other cases as a