My version is the same as Alison's until the first line that ends with vista (but I learned vistey not vista).
FLEA
Each line is echoed back to the leader.
Flea (Flea) Flea fly (Flea fly) Flea fly flo (Flea fly flo) Vistey (Vistey)
Cumala, cumala, cumala vistey
Oh no no no not the vistey
Vistey ( and then it really changes!)
Eeney meney dis a leenee, ooh ahh ahh meleenee Otchicotchee oochirachee, ooh ahh ooh. Ish bibili oaten doten, why not in doten toten, bo bo ski doten toten hey don areema!
This was always a camp song that was lots of fun because you got faster each time until everyone just collapsed in laughter. I've heard other versions but this is the only one I've ever been able to learn.