From my cat rescue:
We have been asked to foster a 9 month old Maine Coon kitten for 6 weeks. The cat has tested negative for FELV/FIV, but they need to retest in 6 weeks. The reason for this is because of the area where the kitten came from. Some of the cats there tested positive, but not all. The kitten would have to be isolated, so someone who can either keep this kitten separate/not have any other cats/kittens. I know not many fosters don't have cats/kittens.