In the interest of accuracy, allow me to expand on what I wrote earlier about pyrethrin, and correct a couple of mistakes or bad choices of wording: -------------------------- Pyrethrin is generally considered safe, when used as directed, for use on pets. It is frequently recommended by veterinarians for use on ferrets. Marshall flea and tick products for ferrets contain a pyrethrin derivative called resmethrin. Pyrethrin has been used many thousands of times, at least, on ferrets with good results. From here on, by "pyrethrin" I mean either plain pyrethrin or resmethrin. It is probably better to avoid other forms of pyrethrin. Cats are known to have reactions to permethrin and possibly ferrets as well. Definitely stay away from any product containing additives or "synergistic compounds", such as piperonyl butoxide, sesamex, piperonyl cyclonene, carbamates, carbamyls. It is likely that additives are actually responsible for many of the health problems that have been attributed to pyrethrin. In the words of one source, these additives "potentiate mammalian toxicity". In other words, they may make the product more poisonous to insects but then they are more poisonous to mammals, too. It may be that ferrets in general are more sensitive to pyrethrin than some other animals are. There is some evidence for this. But it must be pointed out that even if so, pyrethrin is still less toxic than most alternatives you are likely to find.* The choice is yours. There are in fact reports of ferret illness and death from the use of pyrethrin. At the same time, it is not clear that it was pyrethrin itself that was the culprit in most of these cases; it may have been from additives. Further, it has been in common use for a long time, and reported problems have been rare. **IF** you decide to use pyrethrin, I recommend the following precautions, which I will explain more fully than last time: (1) Use plain pyrethrin or resmethrin. Avoid other pyrethrin derivatives. In particular, never use permethrin on your ferret. And "synergistic" additives are definitely out. See the list I gave above and if any of those things are on the label, don't use it. Obviously not all chemicals can be listed here; use your judgment. (2) Pyrethrin should be used outside if possible, for several good reasons. First, pyrethrin is not just an insecticide, it also repels the pests. Fleas, ticks, bedbugs, and mites generally prefer to bite your pets because they have fur and a higher body temperature than humans. But if they are repelled from your animals, they will bite the next best thing: you. Taking things outside gives them an opportunity to just leave instead. Especially if you spray and then leave the area for a while. Second, using insecticides inside can cause concentrations that are not intended or according to directions. Always use insecticide with caution, and use only in well-ventilated areas. If for some reason you feel you need to apply a pyrethrin-based product to your general household or any large part of it, you should open windows for ventilation and go elsewhere for a few hours, to give it time to work and then break down. Best to err on the side of caution. Third, light and oxygen cause pyrethrin to break down faster. Pyrethrin kills pests quickly, but it also breaks down very quickly. These are both good things. It will generally break down in air and be rendered non-toxic (even to insects) within about 4 hours. Taking things outside into the sunlight and the breeze will speed up the breakdown process, as well as giving the vermin a chance to exit to somewhere besides your own pants. So take the items outside, including your pets, and spray them there. (For a ferret, maybe find a way to confine it outside like one of those portable play-area fence things.) Then walk away and leave them be for a while. Earlier I wrote 15 minutes but a half hour would probably be even better. This is not enough time for all the pyrethrin to break down, but it helps, and it is enough time for it to do whatever work it is going to do. Bedding and other such materials should then be laundered with warm or hot water and detergent. I mentioned mattresses last time, but I could have been clearer: since you can't launder these items, after treatment with pyrethrin you should leave them out in the air and sun for a good couple of hours. But keep in mind that if you leave them out long enough for the pyrethrin to degrade completely, the pests might well just crawl back to where they were before. So while you might take them inside, open a window and you probably don't want to cover them or use them for several hours afterward. (3) PLEASE follow the directions. Any household chemical is usually safe if used as directed, but many can be hazardous if they are not. (4) One application of pyrethrin is usually not enough to get rid of a severe pest problem. It kills the adults, but not eggs. It generally has to be done again after a couple of weeks. There are products that claim to kill the eggs, too... but those are the very additives I was warning against. I do not claim that pyrethrin is safe for your ferret. You must decide that on your own. There have been reported cases of problems, and it is possible that pyrethrin was indeed the cause; that is impossible for me to say. All I can say is that it has been used a lot, for a long time, and that the vast majority of the time it has been safe and effective. -------------------------- * This added later: I was referring to alternatives you can find on the shelf, but it appears this has changed. While looking up this information I ran across some other, newer products that are reportedly safer for ferrets, but they haven't been around nearly as long so one must be cautious about such conclusions. One of the newer products is "fipronil", which is sold under the brand names Frontline®, Frontline Plus®, and Top Spot®. Another of the newer products deemed to be "safer" is Advantage®. Advantage works differently from the others. For general advice about treatment and control, please see here: <http://www.merckvetmanual.com/mvm/index.jsp?cfile=htm/bc/71600.htm#aTreatment%20and%20Control> Note: that page is aimed mainly at treatment of cats and dogs, but in the ferret section of the manual it states that ferret treatment should be the same as for a cat. For symptoms of insecticide poisoning, please see here: <http://www.merckvetmanual.com/mvm/index.jsp?cfile=htm/bc/211604.htm> However, it should be noted that contrary to that entry, permethrin appears to be less safe in cats and ferrets than pyrethrin. There may be more authoritative texts for ferrets than the Merck Veterinary Manual, but they tend to be expensive and their content is not available online. Lonny Eachus ============ [Posted in FML 7194]