Also, dust MITES are MITES - wee tiny bugs. I would think you are very unlikely to find them in cat litter. There are all kinds of litter - ask at your local pet store!

The mites are more likely to live in house dust, etc. that has been there for a while. (No reflection on your housekeeping...dust normally lives about everywhere! )

Have a look here - and a warning, the picture on the right is magnified MANY MANY times!

http://en.wikipedia.org/wiki/House_dust_mite