Questions about "slightly positive" FeLV kitten

My other sister (not Megan & Blackbear) is fostering a kitten that tested FeLV+ at 5 weeks and "slightly positive" at 8 weeks. The kitten will be tested again in another 1-2 weeks. My sister volunteers at a shelter where a large litter was left on the doorstep. Out of 9 kittens, four tested positive at 5 weeks and were put into foster care in sets of two. The other kitten my sister had tested negative at 8 weeks so he went back to the shelter for more socializing and adoption. The other 5 negative kittens were kept in isolation and tested negative again at 8 weeks.

Does anyone who has fostered FeLV+ kittens know the likelihood that this kitten will become negative - or will convert to positive? If she was positive earlier and is now only slightly positive, isn't that a good sign that she is headed toward negative?

My sister is wondering about how possible/impossible it is to introduce this kitten to her other cats who are FeLV negative.

Any words of wisdom, links to websites or on line support group(s) would be appreciated. My sister has fostered a lot of animals and her 3 cats and 2 dogs are all rescues, so she is pretty knowledgeable - just has never dealt with this before. I know this kitten is pulling at her heartstrings.

Thanks.

 

Merck Veterinary Manual FeLV