Maybe allergies ??? I've had a cat for 5 years before I had my first born and her daycare also had 2 cats ... My daugther was constantly sick during her first 2 years ... ear infections, colds and coughs ... She even was put on the pump at one point. The doctor did not say SHE WAS allergic and she was still too young to be tested but ... when I finaly said enough is enough and got the cat out ... her health improved drasticaly. She is no longer in daycare obvioulsy. So, my advice to you is let the familiy know you now have a cat and with flu and cold season ...make sure the symptoms are not mistakenly diagnosed.

And as far as preventive measure, all my animals no matter how nice they are, I keep them away from the children during daycare hours ... We never know right.