lice,mites, and worms

Question
We have 7 guinea pigs that have a gotten lice. We keep our guineas with rabbits. The rabbits do not "appear" to have the lice (but they could have it too). We have bathed each guinea pig with Critter Oil and soap which has killed the living lice but not the eggs so we are repeating the process until all the lice are gone. I have 3 questions:
2. One guinea pig, who had the worst infestation, has lost TOO much weight but is active and eating. Could he have gotten some kind of internal parasite from the lice?
2. If he has a internal parasite can I deworm him with our cat dewormer "WRM Clear"by HomeoPet? I would use a small dose.
3. Where do these lice come from? We give our rabbits and guineas Timothy Hay. We also have ducks and chickens in our yard. Could the lice come from them or the hay? Thanks

Answer
Hello Anna

First off NEVER keep guinea pigs with rabbits they arent supposed to eat the same kind of food and rabbit food can contain things that harm the guinea pigs, also rabbits have strong hind legs and can crush a guinea pig if the stomp there feet when the guinea pigs near, rabbits dont get lice they get mites and fleas, I dont know if they could have gotten internal parasites from the lice but I have never heard of such a thing happening, if the hay or bedding has been around lice then it has lice on it and therefore will give the guinea pigs lice, never give anything thats not made for guinea pigs it will kill them call a vet if you think soemthings wrong.