bpatters, do you know anyone whose guinea pig has had mites who has bathed them and observed their guinea pig going wild? I've heard people say this but got the feeling it was "conventional wisdom" and do not have confidence it was an observed behavior. I actually don't know about how the mites would react. Since they live in tunnels under the skin, there are likely pockets of air present in the tunnels. I don't know what their breathing structure is.
If I can get some scientific info, I might add something to the mite page.
I also imagine there are some guinea pig that hate baths.
I'm going to make this temporarily a sticky in case we can get some rescuers or other people who have handled many guinea pigs who can comment.
I had assumed it was more or less because 1: if you treated with invermectin topically, you didn't want to wash it out and 2: most piggies find baths stressful and since they're already infested with mites, you didn't want to add further stress which could potentially lead to more health problems, be it an increase in the mite infestation or something else. I never heard of baths making mites crazy and causing the cavy to become itchier so that was surprising to hear (and now wish there was more info on though I guess then this thread wouldn't likely have been posted then)
I remember reading (a few years ago) an article about treating a guinea pig with mites with some type of medicated bath but I can't remember what they used exactly. I think they did 2 or 3 baths spaced maybe a few days apart and the medication they used for the bath began with an f? It is an old article (I can't remember the year but I believe the treatment occurred in the late 80s or early 90s) and I know treatment/general consensus on care have changed since then but it may be worth looking for just in case. I'll have to go digging and see if I can find it again (unless you or someone else have seen it already?)
I looked but couldn't find anything about mites and water though I wonder if maybe bathing a guinea pig increases itching not so much through the affects of water but because the mites are reacting to an increase in the guinea pig's stress (perhaps some hormonal changes that occur during stress is what drives the mites crazy)...
I'm not sure what mites feed on exactly or how they process information/the world around them but that might be handy to know in trying to figure out the link between bathing guinea pigs and mites
Humans can get scabies (mites). I went looking to see if there were any comments regarding bathing and could find nothing.
I did notice that very few scabies mites would be on a human. Also discovered another human condition where there are thousands of mites ("crusted scabies") and a person is very contagious by contact. Regular scabies doesn't seem to be quite as contagious but still is, most frequently with close personal contact.
Some links I found on human mites:
"A scabies infestation should be handled as a medical problem and is readily diagnosed and treated by most physicians. (Confirmation requires isolating the mites in a skin scraping.) The first step to control a scabies infestation usually involves softening the skin with soap and water to make sure the pesticide treatments can penetrate well. An evening bath followed by overnight treatment works best. A total body (neck- down) application of topical pesticide medication should remain for 8-12 hours before showering in the morning. Commonly used products include lindane (Kwell (tm)), permethrin (Elimite (tm)) and crotamiton (Eurax (tm)). Follow directions on the product package carefully. "