With the exception of two people here ... one who is in fact a vet (but did not respond in this post) and the other who is a vet technician with just as much knowledge, the mission statement of this board is such that the administrator, moderators and members will not and cannot diagnose illness, only advise.
To answer your original question ... ZERO is the percentage of sevin dust you can use to dust your cats with to kill fleas. Just to reiterate in case you didn't catch that ... ZILCH, NADA, NOTHING ... ZERO PERCENT. I seriously doubt that you would want to be doused with a toxic pesticide if you developed a case of fleas yourself. However, if you don't mind the risk of serious complications or even death, then knock yourself out, to each his own.
Oh and as much as we people here suck, we can go on with the proper knowledge that our cats are well cared for and can only pray that a Higher Power will look out for yours.
seven dust
Re: seven dust
Now I'm worried about her cat! 