Occasionally veterinarians are consulted because of skin lesions in pet owners that are thought to be caused by the pet, even if the animal shows few or no problems.
Therefore the veterinary dermatologist should be familiar with the most common zoonotic skin diseases of small animals. The type and the distribution of the skin lesions in animals and in the owners can give important clues to the type of zoonosis and we illustrate here lesions and diseases caused by mites, flease and dermatophytes.
During the 5th Dermatology Congress in Vienna the delegates will have excellent opportunities to attend lectures and practical classes (wet labs) that cover these and other aspects of clinical dermatology and learn about relevant case studies.
EctoparasitesSarcoptes scabiei var. canis and Cheyletiella spp.
Sarcoptes scabiei var. canis mites are host specific and very contagious. Their main hosts are dogs and foxes. Mites are transmitted mostly by direct contact with an infested animal, but indirect transmission is also possible (through vectors or the environment).
Classical signs include a severe, non-seasonal pruritus with a typical distribution pattern (abdomen, ears, limbs). Pruritus occurs at night as well as during the day and worsens in a warmer environment.
Massive secondary changes (bacterial secondary infections, seborrhoea, alopecia, hyperpigmentation, lichenification etc.) following severe self-trauma and generalisation are commonly seen.
 Papular lesions on the human abdominal skin caused by Sarcoptes scabiei infestation.
Humans usually get infected by direct contact with the diseased animal, mostly dogs. Not all in-contact humans become infestated – only 20-30% of them are “attractive” for these mites. Thus, commonly only one person in the household shows the characteristic red itchy papules. They clear after a couple of days, but as long as the animal harbours sarcoptes mites new papules in the affected humans come up, clear again and so on.
|  | The skin lesions in humans are seen in non-protected body regions that come in contact with the animal, mostly on arms, legs or in the upper body. Especially children are commonly affected.
In areas where the fox population is getting larger, the number of foxes suffering from sarcoptic mange also increases, leading to a higher prevalence of sarcoptic mange in dogs, especially hunting dogs. In some regions, foxes have adapted to living close to homes. In this situation non-hunting dogs may also get sarcoptic mites from foxes and may infect their owners.
Cheyletiella are less host specific than sarcoptes mites. They are also very contagious and are transmitted by direct or indirect contact. Their main hosts are dogs, cats and small mammals. Classical signs are scaling and pruritus on the back, shoulders and on the outsides of the pinnae. The intensity of these signs varies from animal to animal, and asymptomatic carriers commonly occur.
 Scaling and inflammation at the skin surface in a dog with cheyletiellosis. Small white objects on the hairs are adult mites.
Most owners get infested through direct contact with an infestated animal. If the animal is an asymptomatic carrier, the skin lesions are only on the owners, especially in the beginning. The skin lesions in humans are essentially the same as described for sarcoptes mites.
 Papules caused by Cheyletiella bites in the neck.
Affected regions vary with the individual, depending on
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