Exotics Flashcards
Encephalitozoon cuniculi
Encephalitozoon cuniculi is a microsporidian parasite of rabbits that causes neurologic and renal disease. This parasite directly infects the lenses of rabbits and causes phacoclastic cataracts (meaning it can break through the lens capsule) and uveitis. (If you were able to identify this, congratulations; that is truly outstanding!) If you were not able to identify this as an Encephalitozoon cuniculi infection, it may still have been possible to reason through this question provided that you identified the white cataract and the signs of uveitis in the picture. If you observed those two things, you should realize that lens removal is the treatment for the cataract and steroids for the uveitis. You would then choose between albendazole and grid keratotomy. There is no corneal disease or ulceration in this rabbit’s eye, and that is what corneal debridement and grid keratotomy are used for. So remember on your exam, even if you are not sure exactly what the image is, you can often reason your way through the answer choices to make a good choice.
An adult male iguana, fed a poor diet high in protein and low in vitamins, presents with a history of lethargy, inappetance and abdominal straining with the voiding of small amounts of red-tinged urates. You palpate a firm mass in the caudal abdomen which is confirmed with radiographs. At this time what is your best diagnosis and therapeutic response?
Iguanas are predisposed to developing large cystic calculi if they are fed an imbalanced/improper diet. Radiographs contribute to the diagnosis, which show classic round cystic calculi within the bladder. If the calculi are large such that they will not pass, surgery may be indicated. In order to promote proper healing and to decrease the chance of calculi recurrence, a balanced diet appropriate for iguanas must be provided.
A 1-year old female guinea pig presents for respiratory distress and weight loss. The guinea pig is housed in a 4x6 foot enclosure lined with newspaper. The guinea pig shares a cage with a 2-year old female rabbit that appears healthy. What is the most likely etiology?
Many rabbits are inapparent carriers of Bordetella bronchiseptica. However, Bordetella causes primary respiratory disease in guinea pigs; therefore, guinea pigs and rabbits should not be housed together. Clinical signs of bordetella in guinea pigs include respiratory distress, weight loss, and sudden death. Pasteurella multocida causes respiratory disease (“snuffles”) in rabbits but not guinea pigs. Mycoplasma pulmonis and Sendai virus are part of a complex of organisms that cause respiratory disease in rats. Teflon toxicity causes respiratory disease in birds but has not been reported to affect guinea pigs.
A full spectrum source of ultraviolet light is required for reptiles for which of the following reasons?
The correct answer is conversion of inactive vitamin D to vitamin D3 in the skin. Animals housed outside with access to direct sunlight usually have adequate amounts of vitamin D3. Vitamin D3 is required for proper calcium absorption and metabolism. Imbalances in calcium, phosphorus, and vitamin D3 can lead to nutritional secondary hyperparathyroidism, fibrous osteodystrophy, osteomalacia, cystic calculi, bone deformities, and rickets. Deficiencies in vitamin D3 can be corrected with parenteral administration of vitamin D3 every 4 weeks. Overdoses of vitamin D3 can lead to soft tissue mineralization.
What is an all seed diet deficient in?
An all seed diet is deficient in vitamin A. Clinical signs include a blunted choanal papilla, rhinitis, sinusitis, and loss of skin and feather quality. Other causes of white plaques in the mouth include Candidiasis, trichomoniasis, capillaria, pox virus, and papillomatosis in birds.
Turtle presents with swollen eyes, ocular and nasal discharge. What is the most likely dx?
Def. of Vit a
What are the clinical signs of Hypervitamanous A?
Hypovitaminosis A most commonly affects box turtles that are fed imbalanced diets of fruit and insects that have little vitamin A. Clinical signs include edema of the eyelids, chronic respiratory disease, renal disease (due to the squamous metaplasia of renal tubules blocking collecting ducts), squamous metaplasia of epithelium, and secondary infections of the eyes, skin, and respiratory system. Treatment includes oral or parenteral vitamin A supplementation.
A boa constrictor presents with a history of regurgitation over the past two weeks and now an inability to right itself. What is your top differential as to the causative agent of the clinical signs?
The correct answer is inclusion body disease. The exact cause of inclusion body disease is not known, but a retrovirus is strongly suspected. Additionally, it seems as though the snake mite, Ophionyssus natricus is associated with the transmission. Dysecdysis is the term for abnormal shedding. A ruptured urinary bladder is impossible as snakes don’t have bladders.
Which of these is the primary means of heat dissipation for a rabbit?
The correct answer is through the ears. Rabbits can only sweat through glands around their lips. They also are unable to dissipate heat efficiently via panting or salivation. Their ears are large, thin-skinned, highly vascularized structures with heat sensing organs and a counter-current heat exchange system. At high temperatures, the blood vessels dilate, increasing ear blood flow and dissipating heat. Because this is their primary means of dissipating heat, rabbits are unable to tolerate very hot ambient temperatures.
Septicemic cutaneous ulcerative disease (SCUD) in turtles is most commonly caused by which pathogen?
The correct answer is Citrobacter freundii. SCUD in turtles causes pitted scutes that slough with underlying purulent exudate. Petechia on the skin and liver necrosis also commonly occur. Prevention is aimed at good husbandry, and chloramphenicol is the treatment of choice.
A proliferative honeycomb beak (as seen in the image below) along with scaly crusty lesions on the legs and feet of a bird can be a sign of
The correct answer is Cnemidocoptes pilae. Cnemidocoptes pilae, is also known as “scaly face” or “scaly leg.” This mite can be treated with topical or oral ivermectin. It is more common in birds that are immunocompromised, and beak deformity may be permanent even after the mite is cleared.
Avian pox can cause skin lesions, diptheric membranes, or septicemia. Mycobacterium avium causes granulomatous disease throughout the liver and GI tract. Chlamydophila psittaci is the causative agent of psittacosis, and causes lethargy, respiratory, and GI signs.
An 8-month old iguana presents for further evaluation of a lack of thriving. On physical exam, a pliable mandible and maxilla are palpated. What is your diagnosis?
The correct answer is metabolic bone disease. Usually, you will see bowing of the long bones with rounding of the skull in addition to the clinical findings mentioned. The disease usually occurs as a result of secondary nutritional hyperparathyroidism. When there is inadequate calcium absorbed from the diet, the parathyroid glands become hyperactive, causing release of calcium stores in the bones, leading to fibrous and pliable bones. Adequate nutrition is key to preventing this disease.
A pet rabbit presents to you for mild dermatitis. On physical exam, you note a scaly dermatosis with areas of thinning on the dorsum. What is the most likely etiology?
The correct answer is Cheyletiella. This is the fur mite of rabbits and typically causes clinical signs as described in this question.
A 7-year old cockatoo presents to you for evaluation of the skin. The owner reports the skin lesions seem to have started shortly after an incident when the bird was “mouthed” by the family dog but did not appear to be significantly injured at the time. On your examination, you note the skin lesions shown in the photo. You perform a biopsy and culture of the region which confirms Staphylococcal dermatitis. Which of the following antibiotics is useful against Staphylococcus when administered orally (including in water or food) in birds?
Amoxicillin is effective against Gram-positive bacteria, especially Staphylococcus. It is absorbed orally and can be administered in water to birds with susceptible bacterial infections.
Metronidazole is useful in birds against anaerobic infections such as Clostridium and some motile protozoa such as Trichomonas, Giardia and Cochlosoma.
Ketoconazole is an antifungal sometimes used for Candida infections. Terbinafine is an antifungal used to treat Aspergillus and dermatophytes.
Gentamicin is toxic to birds.
Oxytetracycline is poorly absorbed orally and is given intramuscularly although it can cause irritation/necrosis at injection sites.
A mouse presents for patchy alopecia on the head. You suspect a dermatophyte infection in the mouse. What is the most common dermatophyte responsible for ringworm in mice and rats?
The correct answer is Trichophyton mentagrophytes. Microsporum gypseum can occasionally cause dermatophytosis in mice but less frequently than T. mentagrophytes. Approximately 98% of the cases of ringworm in cats are caused by M. canis. In dogs, most cases (approximately 70%) are caused by M. canis followed by M. gypseum and T. mentagrophytes. M. nanum typically affects pigs. T. verrucosum typically affects cattle and horses.
