My little Inka also had fleas when she was found in the middle of a cornfield! The vet sprayed a stinky (yuck !!!)product all over her fur ; the same day I could already comb out dead fleas and eggs , and after 2 days , Inka was flea-free !!
btw. there was no danger for my other cat Maya , as I treat her regularly with "frontline" !

Tell us how it goes , hey