I dunno... I got sick a lot as a kid, and I didn't do anything much with other kids till I was about 9 (when I started private school). I'd far rather have gotten it out of the way when I didn't want to actually play with my friends; I once faked not being sick, in order to go to school where all the other kids were! This sort of backfired when I felt awful at lunch and my mom had to come get me...

Of course, some of my getting-sick episodes were probably due to the histoplasmosis. It might be a good idea to make sure that there aren't a lot of blackbirds or bats or the like in the area of the preschool; the symptom of "mysterious fever" is one that the initial histo infection can cause.