A parasitic disease is defined as any disease resulting from the presence of any life cycle stage of parasite. Cheyletiella are mites that live on the skin, causing irritation, dandruff, and itchiness. A distinguishing feature of this mite species are the large, claw-like mouth parts. These mites can be found quite commonly on cats, dogs, rabbits, and other species. Though humans are not a natural host for this parasite, Cheyletiella mites can happily live on humans for a while, causing an itchy rash.
Cheyletiella parasitovorax, also known as walking dandruff, is a mild dermatitis caused by fur mites in rabbits. It’s often referred to as walking dandruff as the mite can sometimes be seen moving under the dandruff scales. It is primarily transmitted by direct contact between infested and non-infested rabbits. The mites can survive in the environment for several days, so spread may also occur through contaminated hay or bedding. The presence of fur mites is not always easy to determine. When present, Cheyletiella parasitovorax is most likely to be found on the dorsum and neck of the rabbit.
Signs and symptoms include thinning of the hair over the shoulders and back, red oily hairless patches over the back and head, dandruff, and mild-to-moderate pruritus. Rabbits may not show any signs of infestation. Though sometimes Cheyletiella mites can be seen moving about on the skin, in many cases they can be quite difficult to find . Diagnosis is made by identification of the mite. This may be possible with the naked eye or using a magnifying glass in heavier infestations. In other cases it may be necessary to examine hair or skin scrapings under a microscope.
Examining dandruff, hairs or scrapings of the skin under the microscope can positively identify the mites or eggs. By combing the coat of an infested rabbit over a piece of black paper and observing the paper for “moving dandruff is another way a diagnosis is made. There are several different treatments available. The veterinarian usually determines which one is best for the rabbit. Most commonly treatment involves a course of either injections or spot on treatments. Dips in lime sulfur and injections of ivermectin have been used to treat an infestation with these mites.
The rabbit should be re-examined at the end of the course of treatment to ensure that the infestation has cleared completely. It is just as important to ensure that the environment is properly treated, in order to avoid re-infestation. This is done by removing all hay, bedding, and toys. Once removed disinfect them thoroughly, then use an insecticidal fog or spray that is effective against Cheyletiella. Some veterinarians recommend preventative treatment with kitten-strength Revolution for rabbits who are particularly prone to mite infestations.
Dosage amount and frequency will be determined by the size of the rabbit, along with its medical history. There is no vaccine available to prevent this disease. Cheyletiella is considered to be a possible zoonotic infection. Most people are exposed through handling of infested pets. Infection is typically transient and self-limiting in people because constant contact with infected animals is needed to maintain infection with humans. Occasionally humans exposed to this parasite will develop mild skin lesions.
These may be itchy and can form open sores in very severe cases. Anyone handling diseased rabbits should thoroughly wash their hands and use appropriate caution to prevent from being infected. Cheyletiella parasitovorax isn’t a reportable disease. I would educate clients about Cheyletiella by use of posters, charts and pictures. I would also send home brochures and websites for them to read over. These materials would describe the cause, symptoms, diagnosis, treatment, and prevention of Cheyletiella.