Lately, I have been wondering how safe it is for humans to be breathing in cat litter. I have read about pregnant women staying away. What about people with immune difficiencies? Could breathing that in have an affect on the immune system? I am asking because I have had mono for the past 14 months, almost as long as I have had my cat! I would never want to get rid of my cat but is there something I can do or do I even have to worry?