I don't worry about them getting parasites from raw. It may happen, but animals can pick up parasites just as easily, if not more so, from other animals, either by direct contact or by covering the same ground infected animals have covered, especially if they've left a stool sample that they just have to check out. This includes those regular vet visits, by the way.
Basically, most of the more basic herbal anti-parsitic, vermicidal treatments we can take, they can take. Not all though. For example, avoid garlic, their systems really can't handle it that well and in some cases it can be poisonous to them, but Black-Walnut hulls, etc. (like in Clarkia ,) are tolerable. Just remember to let the alcohol evaporate first if giving a tincture! You can just add the drops to a bit of boiling water, then let cool. Just a few tablespoons of water is all you need, then you can either pour it over a favorite food or give by oral syringe. (Instructions on oral syringes here and the link immediately below it.)
[Standard disclaimers: Animals are not people and need to have the dosages cut down accordingly from our doses. Then cut it in half or more. Ask a good holistic vet first about the ingredients and dosages, can find many online if there isn't one local.]
In the meantime, cats and dogs' digestive systems are much different from ours. They've evolved (or been created, take your pick) to hunt and eat meat raw. They don't cook it over a nice warm fire first. =) What do zoo keepers, magicians, and circus performers feed their tigers and lions? Raw meat. What do rescue workers and the like feed wolves? Raw meat. Fluffy and Fido are much more closely related to their wild cousins than they are to us.
Raw is actually a very healthy Diet for them. It can become a rather expensive diet, hence the compromise of supplementing with a really good prepared food. Still, at least mostly raw is a better choice for them. Sorry, but if they advertise on TV, it's not a healthy prepared food. I gathered up some good links about diet in the post "Re: Kitty has colitis" just a little further down, so I won't repeat them all here. In that post, check out Shirley's Wellness Cafe. Losts of good, detailed information of feeding raw can be found there.