FIV infected Kitten

[HillegondH]

I have been researching the net for information on FIV in kittens and hope to get more info here. My daughter came home two weeks ago with a little freal kitten appr. 5 weeks old. We already hav a 3 year old cat and had not planned on another cat, but ofcourse everybody in the family fell in love with this little thing. Yesterday we were told she tested positive for FIV, which realy upset everybody, but we have decided to keep her and deal with things as they come. Now I read that when a little kitten tests positive, you need to keep testing it until at least 6 month of age because it might be mothers anti-bodies, passed through mothers milk that might make the test come back positive. Is there anybody in this forum that indeed had that happen, meaning that at first the test came back positive but later negative? I know we are grasping at straws, but hope helps. We are also trying to decide whether to keep the two cats separate for ever or introduce them anyhow, I will talk to the vet to have the older one tested too now and if that comes back negative, to have him vacinated, but wonder whether that would be sufficient protection. Any advise??