Articles Index/Cheyletiella Mite
Created 09/21/98


The Cheyletiella mite afflicts dogs of any age but, at least in Norfolks, is most often associated with puppies. Symptoms are itching, scratching, and the appearance of white, scaly dandruff, usually appearing in the area from the top of the head, down the back, to the base of the tail. The condition is frequently referred to as "walking dandruff," as the mite is large enough to be seen with a magnifying glass and may be observed as tiny white specs moving through the fur.

Diagnosis is generally confirmed by microscopic examination of skin scrapings or hair combings. The mite has four pairs of legs bearing combs instead of claws and distinctive accessory mouth parts with the appearance of a "Viking helmet." There are three common varieties distinguished by distinctively shaped sense organs: Cheyletiella yasguri, Cheyletiella blakei, & Cheyletiella parasitovorax, respectively associated primarily with dogs, cats, and rabbits. Mites, like spiders, are members of the arachnid family.

The Norfolk community has been aware of Cheyletiellosis for years and it has been addressed in both editions of Joan Read's The Norfolk Terrier. Unfortunately, there seems to be a lot of misunderstanding about this matter.

Many Norfolk litters have this mite. But Cheyletiella is not nearly so severe as either Demodex or Sarcoptes. Thankfully, treatment is usually simple: Shampoo two or three times at about seven-to-ten-day intervals with a canine product that contains pyrethrins or carbaryl.

How Serious Is It?

From where I sit, it appears that all too often, when a puppy is diagnosed with this mite by a vet, the puppy owner is given the impression that it is a far more serious problem than we in the breed have found it to be. One of the last conversations that I had with Joan Read before her death was about this very matter, wherein someone had called her for advice after being scared out of her wits by her vet -- to the extent that the buyer could not be pacified and the breeder had to retrieve the puppy. I have wondered why this is so and have conducted some, admittedly informal, research.

First, my vet has shared with me excerpts from four veterinary texts. Understandably, they all present Cheyletiellosis under the general heading of parasitic diseases of the skin. In two, Cheyletiellosis is immediately followed by Demodicosis and in the third it is immediately preceded by, and accompanied with, discussion of Sarcoptes. In the fourth, I don't know what precedes it and an article about lice follows.

Second, limited inquiry suggests that, while Cheyletiellosis is not just a Norfolk problem, it is not equally common in all breeds. I believe that, while most veterinarians can readily and properly diagnose this mite, they may be relying on veterinary texts rather than their personal experience in the perspective they offer about the infestation. The Textbook of Veterinary Internal Medicine, 4th edition, Ettinger & Feldman, states:

 "It is commonly believed that this disease is easy to treat and that many owners eliminate infestations on their pets by using flea shampoos or sprays. My experience, especially during the past several years, has been strikingly different."

The opinion expressed in the above quote is contrary to the experience of many Norfolk breeders.

Third, I have looked into the life stages of this mite. It is a surface-dwelling parasite that is spread by direct contact and has egg, larva, nymph, and adult stages, completing the cycle in three weeks, typically on one host. The adult female is believed to live up to ten days free from the host.

Persistent Pest

There is little discussion in the literature as to how long the mite can survive in the environment. Anecdotal experience is that puppies can turn up with an infestation at two to three weeks even though the whelping area is apparently "clean" and the breeder has not whelped a litter in months. I found one report from Korea of a Whippet that was hospitalized for multiple fractures and that apparently developed Cheyletiellosis after two months of hospitalization. No infestation had been apparent when the dog was admitted and the conclusion was that immunosuppression due to extensive use of prednisolone may have initiated the outbreak.

This supports my belief that Cheyletiella may be present, in some stage, on the dogs all the time and, like Demodex, only takes hold when the system is stressed or affected by hormones, drugs, or other circumstance.


Shampooing of the pregnant bitch two to three weeks before whelping tends to reduce the incidence and severity of any outbreak. As puppies under six weeks should not be exposed to insecticides, shampooing at two to three weeks before whelping provides time for any residual chemicals on the bitch to dissipate. Additionally, the bitch's teats and underside may be cleaned with rubbing alcohol as a further precaution. (A shampoo manufacturer advised me that, while there has been no specific testing with pregnant bitches, pyrethrins are generally considered to be safe as they stay on the skin and fur and are not absorbed into the dog's system.) As always, consult with your own veterinarian regarding the care and treatment of your dog.

The question can be asked whether it is "normal" to have this mite in Norfolks. Some breeders report that they never had the mite until another "line" was introduced or that they have more than one breed and only certain of their breeds seem to be disposed toward this mite. This suggests that the mite may not be "normal" and perhaps research should be encouraged in this area. But Cheyletiella is much the same as round worms or ear mites. None is "normal." We do not get alarmed by them; rather we do our best to eliminate them from the dog and the environment.

In conclusion, we should all inform ourselves about this mite and breeders should be up front with their clients about the presence of Cheyletiella in our breed.

Ed Plummer
ANTIC, September, 1998

Cheyletiella Mite

Demodectic Mite

Sarcoptic Mite

Demodectic and Sarcoptic Mites require much stronger magnification to view than Cheyletiella.



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