Avian and Exotic Animal Dermatology

CHAPTER | 15 Avian and Exotic Animal Dermatology





Parasitic



Acariasis



Features


Common mites of avian and exotic animal pet species are generally species specific (Table 15-1). Fur mites generally cause dandruff and patchy alopecia with little associated pruritus. The rabbit fur mite (Cheyletiella parasitovorax) is considered zoonotic, causing mild hyperemia and pruritus in humans. The ear mite, Otodectes cynotis, is commonly found in ferrets and can spread between cats and ferrets; therefore it is important to treat all susceptible pets in the household. The presence of black earwax in ferrets does not necessarily denote ear mite infestation. The rabbit ear mite, Psoroptes cuniculi, can cause such an accumulation of dry crusts that an upright ear can be weighted down into the lop-ear position. Demodex spp. are commonly demonstrated in hamsters greater than 2 years of age with concomitant Cushing’s disease. Hamsters are generally exposed to the mites when young but do not exhibit clinical signs until immunocompromised. Rabbits and guinea pigs with intense pruritus should be checked for their respective mites because this would be the most common differential. Birds, typically budgerigars and canaries, infected with Knemidokoptes generally show pitting of the beak and facial skin (budgerigars), or pitting of the skin of the legs (canaries). Snake mites (Oophyionysus spp.) can be found anywhere on the snake’s body, but typically they can be found around the eye or between the cleft of skin under the chin. Severe infestations in snakes can cause significant anemia. African hedgehogs kept as pets in the United States can present with Chorioptes spp. mites, resulting in quill loss and skin crusting and flaking.


TABLE 15-1 Common Mites of Avian and Exotic Animal Pets





























































































Mite Characteristics
Fur Mites
Mouse
Myobia musculi Found over head, neck, and shoulder area
Radfordia affinis  
Myocoptes musculinus Found over entire body
Rat
Radfordia ensifera  
Rabbit
Cheyletiella parasitovorax “Walking dandruff mite,” zoonotic
Listrophus gibbus  
Ear Mites
Rat
Notoedres muris  
Rabbit
Psoroptes cuniculi Dry crusts in ear canal and pinna
Ferret
Otodectes cynotis Dark, waxy discharge in ears
Hamster
Notoedres notedres Found over ears, nose, feet, and anus
Skin
Hamster Common secondary to Cushing’s disease
Demodex criceti Found in epidermis
Demodex aurati Found deep (hair follicles, sebaceous glands)
Guinea Pig
Trixacarus caviae Marked purities: neck, shoulder, inguinal
Chirodiscoides caviae Nonpruritic: lumbar, lateral rear limbs
Rabbit
Sarcoptes scabiei Intense pruritus, self-mutilation
Budgerigars and Canaries
Knemidokoptes pili “Scaly leg and face mite,” pitting beak, skin
Snake
Ophionyssus natricis Check crypts around eye and cleft under chin
Hedgehog
Chorioptes spp. Quill loss; skin crusting and flaking




Treatment and Prognosis


In general, the treatment for mites in most species is ivermectin at 0.2 mg/kg PO, SC, or preferably topically repeated in 10 to 14 days, with some important exceptions: never use ivermectin in turtles or tortoises—it can cause paralysis, coma, death as a result of their permeable blood-brain barrier; never inject ivermectin into birds, especially small birds, as the propylene glycol base can cause an anaphylactic reaction and death.

















Pediculosis







Subcutaneous Parasites







Myiasis, Flea or Tick Infestation






Bacterial



Rabbit Syphilis (Treponema cuniculi)




Top Differentials


Differentials include acariasis (see Figure 15-3) and papillomavirus, (see Figure 15-45), which typically involve other areas of the body than the mucocutaneous junctions.





Ulcerative Pododermatitis—rabbit (sore hock), bird (bumblefoot)






Treatment and Prognosis





Birds


Birds with mild pododermatitis may improve with husbandry changes such as a wider perch, a perch with varying diameters, a padded perch, improved diet with less fat or fewer calories or with needed vitamin A, and, most important, increased exercise. If infection is present, then surgery or long-term antibiotics based on culture (both aerobic and anaerobic) and bandaging may be necessary. A variety of bandages have been described, such as “ball,” where the foot is bandaged into a ball; “snowshoe,” where the bandage is flat-bottomed to disperse the weight over a larger surface area; or a bandage that puts no weight on the bottom of the foot because a U-shaped bar is strapped to the leg. The prognosis is guarded to grave for moderate and severe pododermatitis, respectively.








Mycobacteriosis—bird







Bacterial Dermatitis—bird, ferret






Treatment and Prognosis


Clean and débride the wound; this is sometimes repeated over the course of days. Primary closure is performed once infection is controlled. Birds’ heterophils lack myeloperoxidase, an enzyme that liquefies pus; therefore do not place drains in the wound. Contaminated wounds are treated as in other animals. Antibiotic is based on culture.












Sepsis in Reptiles versus Shedding





Sep 10, 2016 | Posted by in SMALL ANIMAL | Comments Off on Avian and Exotic Animal Dermatology
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