Lice--Where do they come from?! Eek!

Question
Sandra,

Thank you in advance for your insight.  You do wonderful work, as so many vets are ignorant in regard to rats, rodents, and exotics in general.  I am in vet school, and I hope to be an exception.  :)

I used to work for an exotics vet, so I know rats can be treated with Revolution.  Is is true, though, that rats can have subclinical lice all of the time?  Do they come from bedding?  They are species specific, right?  Are they transferable to guinea pigs?

A history:  Gertrude is a rat that I rescued about two years ago.  She has had a persistent head-tilt since adoption, but otherwise checked out okay by my vet.  She is very slow in her movements, and has recently been separated from her cage mate of those two years due to a few random attacks, most recently resulting in a severe abscess.  That finally healed two days ago.  This morning, as I was holding her, she seemed to have "dandruff" (brown speckles), which I did not see yesterday.  This evening, I held her under better light, and she was teeming with lice!  Should I take her into the vet again, or just treat with Revolution, bathe, and repeat in two weeks or so?  Obviously, I'll be disinfecting her cage as well.  I am worried about where these little guys came from . . . I use a paper-type litter, but I've recently started giving her a little Timothy hay.  Could that be the culprit?

Thanks again!  

Siri

Answer
Hi Siri


Yes, it is true that ectoparasites are subclinical all the time. Its not uncommon to see a heavy infestation of lice or mites when a rat is ailing and their immune system is weakened. They are species specific and sometimes host specific. Cavy can get them too, btw, but usually not transferred from the rat to the piggie.

Just recently, my boy, Smudge, who has been sick with heart disease for several months, out of the blue, was loaded with them. I picked him up during one of his panic attacks he has when he gets overly excited and when he calmed down, I put him back in his little ball he stays in (he is also totally blind) and I felt like something was crawling on me.  I grabbed my magnifying glass and zoomed in on these little slivers that were moving on my shirt and chest. Ewww...that just freaked me out.  My poor rat, basically he is terminal and now he has lice. It hit me that he has them probably due to his immune system and so I pulled out some notes on my computer and sure enough this was one of the causes that will "awaken" the critters.  
Its not uncommon after, for example, you euthanize a rat that had been pretty sick and much to his owners horror you find parasites just covering the poor animal. The owner swears they were not there before.

However, they can also come in from outside sources. Bedding of any kind, from aspen (which I use) to the timothy hay too. By the way, I dont suggest using timothy hay for one reason: They have been known to poke rats in the eyes and cause infection if not damage to the eye leading to enucleation!  I use it for my bunny but I break it up into small pieces so there are no big long pieces that can poke him.

What you can do is start freezing any new bedding/litter that you bring in, and this includes their food if you dont make your own rat chow.

I love revolution and used it right away on my sick boy, although I thought I killed him for a second, because he went nuts on me after I put the drop between his shoulder blades and I had to calm him down for a good bit. Luckily he isnt hypoxic but he has these strange episodes where he will just come flying out of the safety of his ferret ball, run around the cage freaking and goes back inside and calms down. He has fast respirations and uses all of his muscles to breathe and no medication is helping so its just a day by  day thing that I start out by deciding if I am going to bring him in to put him down or let him go longer.  He eats like a champ (baby food and dried oatmeal if you call that eating) and he sleeps all curled up in a ball when he rests so he does get comfortable, but I question the quality of his life. I hate this part of rat owning I know that much.  At least I was able to make him comfortable though and his lice are gone.

So that said, hope this helped you today and thanks for the kind words. Thats awesome your a vet student. That was my dream, unrealized of course, and so I wish you the best of luck.  Have you thought about a specialty in exotics?  With the new specialty now, "exotic companion mammal veterinary medicine"  now being offered, I am so excited that our small mammals will FINALLY have vets for their very own. Now, to get the vets to go that route and put that extra effort into it is another story. I was talking with a vet the other day who told me that many vets dont go into exotics fearing that there is no money in it since many small mammal owners do not seek medical attention for their small pets. I told her I can think of several thousand across the United States that can only DREAM of having a good vet for their rat or hamster or ferret!!