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.
A newly acquired Cockatiel with an unknown history presents for increased respiratory effort. Which of the following is the least likely differential diagnosis for this bird?
The correct answer is Polyoma virus infection. The avian Polyoma virus causes delayed feathering, diarrhea, gastrointestinal stasis, ascites, and death. Respiratory difficulty is not a classic clinical sign for Polyoma virus. Mycoplasma infection, chlamydiosis, and Bordetella infection are all respiratory infections in birds that can cause head shaking, sneezing, and rhinitis.
A first-time rabbit owner brings in his one-year old doe for a routine physical examination. He wants his rabbit to live longer than him. Though you know this isn’t possible, you know that to increase her chances of a longer life, you recommend an ovariohysterectomy. What is your primary concern?
The correct answer is an increased risk for uterine adenocarcinoma. Though all the other choices are potential concerns, uterine adenocarcinoma affects greater than 55% of intact females at 3 years of age and older.
What renal diseases is most common in hamsters?
The correct answer is amyloidosis. There is no effective treatment. Hamsters can develop glomerulonephritis, pyelonephritis, or acute tubular nephrosis, but amyloidosis is far more common in older hamsters.
A dwarf rabbit presents for a right sided head tilt and history of circling to the right. Which of the following is a likely diagnosis?
The correct answer is Encephalitozoon cuniculi. There is a high prevalence of E. cuniculi although it only infrequently causes disease. Head tilt and torticollis are the common clinical signs. Treponema cuniculi is the causative agent for rabbit syphilis. Bordetella bronchiseptica is part of the normal flora of the rabbit respiratory tract and does not generally cause clinical signs. Myxomavirus can be a common cause of pneumonia.
An adult chameleon was purchased by an owner one year ago and presents to your clinic with signs of anorexia, decreased activity, and lameness of its left rear leg. The majority of the new owner’s chameleon’s diet is cat food with occasional insects. The chameleon’s enclosure is temperature-regulated and has multiple features on which to climb and hide. Given the history and clinical presentation, which of the following answers is the correct diagnosis?
The correct answer is articular gout. The key to this question is to note the feeding of cat food. Cat food is too high in protein for reptiles. Reptiles have an inability to process large amounts of protein, thus uric acid may subsequently deposit in the joints. Furthermore, chameleons are primarily insectivorous so the diet is inappropriate. Therefore, this is the most reasonable answer for this presentation in a captive chameleon on a sub-optimal diet. Cat food would not be expected to cause metabolic bone disease or hepatic lipidosis.
You are called out to examine a 4-year old dromedary who was castrated 10-days ago and is now not eating. The groin and prepucial area is extremely swollen. The camel is unable to stand and is drooling. His neck is extended and he appears to be unable to swallow. Which of the following is most likely responsible for these symptoms?
This camel is showing signs of tetanus. The organism was likely introduced into the body through the castration wound. It is recommended that camels are vaccinated against tetanus prior to castration. Reference: Trop Anim Health Prod. 2004 Apr;36(3):217-24.
While rabies may cause paralysis of the tongue and difficulty swallowing, the recent history of castration in this camel makes tetanus most likely.
Trypanosoma evansi is transmitted via biting flies and causes a slow wasting disease in camels.
A 6-year old Sun Conure presents for evaluation of a skin lesion. The owner reports that the bird is very sensitive on the wing near the lesion. On your exam, you note an oval swelling involving the feather follicle as seen in the image below. What is the best treatment for feather cysts?
Feather cysts are the avian equivalent of an ingrown hair. A growing feather is unable to protrude through the skin and curls within the follicle. Since feathers are much larger than hairs, cysts can be quite large and painful. They commonly are found in the primary feathers of the wing. The cysts contain keratinized feather material that can be expressed or excised but commonly recur. Treatment of choice is surgical removal of the involved feather follicle.
What type of urolith is common in ferrets?
The correct answer is struvite. A 2011 study showed that sterile struvite was the predominant mineral in uroliths in ferrets. The second most common is calcium oxalate. The other types of uroliths are relatively uncommon in ferrets.
What is the treatment for an insulinoma?
Medical management consists of prednisone and diazoxide alone or in combination. Dietary management with a high protein and low carbohydrate diet is also important. Surgical removal of the tumor is also an option in otherwise healthy ferrets.
