This article talks specificly about cats and internal parasites, including worms and protozoan problems. Uninvited Guests Discusses roundworms in kittens and explains that even healthy kittens could become infected. The article goes into details on the tapeworm lifecylce. A Nasty Nuisance Contains lots of information on what tapeworms actually are, problems with tapeworms, deadly varieties and treatment options. Ear Mites Ear mites can often be overlooked or dismissed as simply dirty ears.
Ear mites can show up as a brown build up on the inside of cats ears.
The cat often will spend a lot of time shaking their head or scratching their ears. Ear mites can dangerous and cause other problems if not treated. I have read stories of rescued cats have such serious eat mites infection that they have had to have their ear amputated. I have a cyper-friend whose lynx had a mild case of ear mites that went undetected. Treatment is relatively simply for us, but we were already treating for fleas and ringworms which may have helped us out.