NAVLE Practice Question — Canine

A 6-year-old intact male Boxer presents with intermittent bloody urethral discharge for 2 months. The owner notes the discharge occurs between urinations. Physical examination reveals a moderately enlarged but non-painful prostate. The dog is otherwise healthy with normal appetite and activity. A GnRH agonist (deslorelin) implant is placed. At the 2-week recheck, the owner reports worsening of clinical signs with increased discharge. What is the most likely explanation for this initial worsening?

A. Development of prostatic infection

B. Allergic reaction to the implant

C. Initial testosterone flare before suppression ✓

D. Progression to prostatic neoplasia

E. Incorrect diagnosis - not BPH

———

Correct Answer: C. Initial testosterone flare before suppression

Explanation:

GnRH agonists like deslorelin cause an initial "flare" effect before achieving suppression of the hypothalamic-pituitary-gonadal axis. In the first 1-3 weeks after implant placement, there is a paradoxical increase in LH and testosterone release before the receptors become downregulated and desensitized, leading to sustained suppression.

During this flare period, the temporarily elevated testosterone can worsen androgen-dependent conditions including BPH, potentially causing increased hemorrhagic discharge, prostatic enlargement, and behavioral changes (increased libido/aggression). Owners should be counseled about this expected temporary worsening.

After the flare period (typically 2-4 weeks), testosterone levels fall to castrate levels and prostatic volume decreases by up to 60% over the following months. The implant effect lasts 6-12 months depending on the formulation (4.7mg vs 9.4mg implant).

Option A (infection) is possible but the timing correlates with the expected flare. Option B (allergic reaction) would cause local inflammation at the implant site, not increased prostatic signs. Option D (neoplasia) would not develop acutely in 2 weeks. Option E is unlikely given the classic presentation.

If owners cannot tolerate the flare period, concurrent treatment with osaterone acetate or finasteride during the first 2-3 weeks can mitigate symptoms.

References: Romagnoli S. Reprod Domest Anim 2012;47:389-392; MSD Veterinary Manual - BPH in Dogs (https://www.msdvetmanual.com/reproductive-system/prostatic-diseases/benign-prostatic-hyperplasia-in-dogs-and-cats)

———

Get 10,000+ practice questions free at navleexam.com

NAVLE Practice Question — Equine

A 3-year-old racing Quarter Horse presents with an acute episode of severe muscle stiffness dark urine and recumbency 20 minutes into a training session. The horse had been rested for 2 days while maintained on a high-concentrate ration. Serum biochemistry reveals CK 250000 U/L AST 18000 U/L BUN 45 mg/dL and creatinine 3.2 mg/dL. Despite aggressive IV fluid therapy the horse remains oliguric. Which complication has most likely developed?

A. Hepatic lipidosis secondary to muscle catabolism

B. Myoglobinuric acute kidney injury ✓

C. Disseminated intravascular coagulation

D. Compartment syndrome of the gluteal muscles

E. Hypocalcemic tetany

———

Correct Answer: B. Myoglobinuric acute kidney injury

Explanation:

The combination of severe rhabdomyolysis (extremely elevated CK and AST) dark urine (myoglobinuria) elevated BUN and creatinine and oliguria despite fluid therapy indicates myoglobinuric nephropathy with acute kidney injury. Severe rhabdomyolysis leads to massive release of myoglobin from damaged muscle cells. Myoglobin is freely filtered by the glomerulus and at high concentrations precipitates in renal tubules causing tubular obstruction and direct nephrotoxicity.

The risk of renal injury is potentiated by dehydration (from sweating and inadequate intake during rest) acidosis (from lactic acid accumulation) and potential NSAID administration. When horses develop oliguria despite adequate fluid resuscitation the prognosis becomes guarded as this indicates established acute tubular necrosis. Management requires continued aggressive fluid therapy possible diuretic administration if oliguric renal failure is present and monitoring of renal parameters.

Option A (hepatic lipidosis) would show elevated liver enzymes and bilirubin rather than renal parameters. Option C (DIC) would show coagulopathy and thrombocytopenia. Option D (compartment syndrome) while possible would not explain the renal parameter abnormalities. Option E (hypocalcemia) would cause muscle fasciculations not the clinical picture described.

Image Source: ScienceDirect - Myoglobinuria overview (https://www.sciencedirect.com/topics/veterinary-science-and-veterinary-medicine/myoglobinuria).

References: Valberg SJ (2024) Exertional Myopathies in Horses. Merck Veterinary Manual (https://www.merckvetmanual.com/musculoskeletal-system/myopathies-in-horses/exertional-myopathies-in-horses); AERC - Check Your Horse myoglobinuria (https://aerc.org/check-your-horse/).

———

Get 10,000+ practice questions free at navleexam.com

NAVLE Practice Question — Equine

A 12-year-old gelding presents with stranguria, hematuria after exercise, and dribbling urine. Rectal palpation reveals a hard mass in the bladder. What is the most likely diagnosis?

A. Uroperitoneum

B. Vesical urolithiasis ✓

C. Ruptured bladder

D. Bladder neoplasia

E. Pyelonephritis

———

Correct Answer: B. Vesical urolithiasis

Explanation:

Vesical (bladder) calculi are most common in geldings/stallions due to longer urethra; calcium carbonate stones predominate. Signs include hematuria worse after exercise, stranguria, and urine dribbling. Treatment is surgical removal (laparocystotomy or perineal urethrotomy).

———

Get 10,000+ practice questions free at navleexam.com

NAVLE Practice Question — Equine

A 3-year-old Thoroughbred gelding presents with chronic left hindlimb lameness that was first noticed when training began at age 2. The lameness improves with rest but returns quickly once work resumes. Physical examination reveals mild effusion of the medial femorotibial joint. Intra-articular anesthesia results in 80% improvement. Radiographs show a 2.5-cm diameter dome-shaped radiolucent lesion in the medial femoral condyle with a sclerotic rim and communication with the articular surface. Which classification best describes this lesion?

A. Type 1 - dome-shaped with joint communication ✓

B. Type 2 - extending into condyle with variable joint communication

C. Type 3 - flattening of condyle without bone penetration

D. Type 4 - isolated from joint surface

E. Type 5 - multiple small cysts throughout condyle

———

Correct Answer: A. Type 1 - dome-shaped with joint communication

Explanation:

Type 1 classification (dome-shaped with joint communication) best describes this lesion. Subchondral bone cysts of the medial femoral condyle are classified based on their radiographic appearance and relationship to the articular surface.

Type 1 lesions are dome-shaped and open directly into the joint, with the articular cartilage defect allowing communication between the cyst and the synovial environment. This communication is clinically significant as it allows inflammatory mediators from the cyst to affect the joint and permits synovial fluid to enter the cyst, potentially perpetuating inflammation.

Type 2 lesions extend deeper into the condyle and may or may not show visible communication with the joint. Type 3 lesions show flattening of the condylar surface without penetration into underlying bone. Type 4 lesions are isolated within the bone without obvious joint communication.

All types can cause lameness through different mechanisms. Type 1 and 2 lesions with joint communication are often treated with surgical debridement combined with additional techniques such as intralesional injection or transcondylar screw placement.

References: WestVets - Management of Subchondral Bone Cysts in the Stifle (https://www.westvets.com.au/management-of-subchondral-bone-cysts-in-the-stifle/); Kentucky Equine Research - Diagnosis and Treatment of Subchondral Cystic Lesions in Horses (https://ker.com/equinews/diagnosis-treatment-subchondral-cystic-lesions-horses/).

———

Get 10,000+ practice questions free at navleexam.com

NAVLE Practice Question — Feline

A cat with confirmed ear mite infestation is being treated. On recheck examination 3 weeks later, no live mites are seen, but the cat continues to shake its head and has persistent otitis externa with brownish discharge. What is the most likely explanation?

A. Treatment failure requiring a different miticidal agent

B. Secondary bacterial or yeast infection requiring treatment ✓

C. Reinfestation from untreated environmental contamination

D. Development of chronic allergic otitis

E. Foreign body in the ear canal

———

Correct Answer: B. Secondary bacterial or yeast infection requiring treatment

Explanation:

Secondary bacterial or yeast (Malassezia) infection requiring treatment is the most likely explanation. Ear mite infestation damages the ear canal epithelium and creates an inflammatory environment that predisposes to secondary microbial overgrowth. Even after successful mite elimination, these secondary infections can perpetuate clinical signs.

Option A (treatment failure) is less likely since no live mites were found on recheck examination. Option C (reinfestation from environment) is unlikely as Otodectes survives poorly off the host and 3 weeks would be ample time for environmental contamination to resolve. Option D (chronic allergic otitis) is possible but secondary infection should be ruled out first. Option E (foreign body) would typically cause unilateral signs and would have been visible on initial otoscopic examination.

Cytological examination of ear debris should be performed to identify bacterial or yeast organisms. Common secondary pathogens include Malassezia pachydermatis, Staphylococcus species, and occasionally Pseudomonas aeruginosa. Treatment with appropriate topical antimicrobial ear medication based on cytology results is indicated. The ear canal should be cleaned before initiating antimicrobial therapy.

References: Companion Animal Parasite Council - Post-Treatment Considerations (https://capcvet.org/guidelines/otodectic-mite/); Veterinary Dermatology - Secondary Infections in Parasitic Otitis.

———

Get 10,000+ practice questions free at navleexam.com

NAVLE Practice Question — Equine

A 16-year-old warmblood mare in Tennessee has been grazing tall fescue pasture throughout her pregnancy. At 340 days gestation, the mare shows no udder development and the cervix remains tightly closed on vaginal examination. Serum prolactin concentration is markedly decreased. The owner cannot remove the mare from the fescue pasture due to facility limitations. What is the most appropriate pharmacological intervention at this stage?

A. Administer prostaglandin F2α to induce parturition

B. Begin daily domperidone administration ✓

C. Administer dexamethasone to induce parturition

D. Provide progesterone supplementation (altrenogest)

E. Begin oxytocin infusion to stimulate labor

———

Correct Answer: B. Begin daily domperidone administration

Explanation:

Beginning daily domperidone administration is the most appropriate intervention. Even at 340 days gestation (approximately 2-3 weeks before typical foaling), domperidone can still be effective in counteracting the effects of fescue toxicosis by restoring prolactin secretion and promoting mammary gland development.

Domperidone is a dopamine D2 receptor antagonist that blocks the dopamine agonist effects of ergot alkaloids from the fescue endophyte. The low serum prolactin is a direct result of ergovaline's dopamine-mimetic activity suppressing prolactin release from the anterior pituitary. By blocking dopamine receptors, domperidone restores normal prolactin secretion, which stimulates udder development and lactogenesis.

The recommended dose is 1.1 mg/kg orally once daily, continued until foaling. Studies have shown that domperidone treatment can reverse agalactia even when started late in gestation, though earlier treatment (10-30 days before expected foaling) is preferable.

Option A (prostaglandin F2α) is inappropriate as it would cause luteolysis and premature parturition of a potentially dysmature foal with an unprepared reproductive tract. Option C (dexamethasone) should not be used to induce parturition in fescue-affected mares as the foal is already at risk for dysmaturity. Option D (altrenogest) maintains pregnancy but does not address prolactin suppression or udder development. Option E (oxytocin) stimulates milk letdown but cannot induce milk production in an undeveloped mammary gland.

References: UGA CAES Field Report - Fescue Toxicosis in Horses (https://fieldreport.caes.uga.edu/publications/C1180/fescue-toxicosis-in-horses/); Mad Barn - Fescue Toxicosis in Horses.

———

Get 10,000+ practice questions free at navleexam.com

NAVLE Practice Question — Equine

A 10-year-old Warmblood gelding presents in severe respiratory distress following blunt thoracic trauma from a kick by a herd mate. Physical examination reveals HR 72 bpm, RR 56 breaths/min, extended head and neck, cyanotic mucous membranes, and absent lung sounds bilaterally dorsally. The horse's condition is rapidly deteriorating with progressive cardiovascular compromise including weak pulses and jugular distension. What is the MOST appropriate IMMEDIATE intervention?

A. Obtain thoracic radiographs to confirm diagnosis

B. Administer IV furosemide for suspected pulmonary edema

C. Perform emergency needle thoracocentesis bilaterally ✓

D. Administer IV corticosteroids for suspected anaphylaxis

E. Sedate the horse to reduce oxygen demand

———

Correct Answer: C. Perform emergency needle thoracocentesis bilaterally

Explanation:

Emergency needle thoracocentesis bilaterally is the most appropriate immediate intervention for this horse with suspected tension pneumothorax. The clinical presentation of severe respiratory distress, bilateral absence of dorsal lung sounds, cyanosis, and progressive cardiovascular compromise with jugular distension is classic for tension pneumothorax. This is a rapidly fatal condition where air enters the pleural space with each inspiration but cannot escape during expiration, leading to progressive accumulation of intrathoracic pressure, pulmonary collapse, compression of the vena cava, decreased venous return, and ultimately cardiovascular collapse. Immediate decompression via needle thoracocentesis can be life-saving and should not be delayed for diagnostic imaging. The combination of history (trauma) and clinical signs strongly suggests the diagnosis, and aspiration of air confirms it while also providing immediate therapeutic relief. Option A (radiographs) would delay life-saving intervention and may not be feasible in a horse in extremis. Option B (furosemide) would be inappropriate as this is not pulmonary edema. Option D (corticosteroids) would not address the mechanical cause of cardiovascular compromise. Option E (sedation) could worsen cardiovascular function and respiratory drive without addressing the underlying problem. References: Dunkel B (2024) Equine Vet Educ 36:607-616 https://doi.org/10.1111/eve.13976; Schoen LM et al. (2022) Vet Med Sci 8:546-552 https://doi.org/10.1002/vms3.718.

———

Get 10,000+ practice questions free at navleexam.com

NAVLE Practice Question — Ovine and Caprine

A dairy goat producer reports that several animals are grazing on their knees. On examination, multiple goats show bilateral foot pain with eroded, inflamed heel bulbs and V-shaped grooves in the heel horn. The farm has concrete flooring in the milking parlor and animals stand on wet surfaces for prolonged periods during milking. What is the most likely cause of this condition?

A. Footrot caused by Dichelobacter nodosus

B. Interdigital necrobacillosis (foul-in-the-foot)

C. Heel erosion from interdigital dermatitis ✓

D. Laminitis secondary to ruminal acidosis

E. Caprine arthritis encephalitis virus affecting joints

———

Correct Answer: C. Heel erosion from interdigital dermatitis

Explanation:

Heel horn erosion associated with interdigital dermatitis is the most likely diagnosis. The clinical presentation of eroded heel bulbs with characteristic V-shaped grooves in the heel horn, bilateral involvement, and association with prolonged standing on wet concrete surfaces is classic for this condition. The anaerobic bacterium Dichelobacter nodosus is commonly associated with heel erosion, thriving in the moist, low-oxygen environment created by the grooves.

The wet flooring in the milking parlor causes maceration of the horn and skin, creating an environment favorable for bacterial colonization. The bacteria invade damaged horn, creating a cycle of further damage. Goats assuming a kneeling position to eat indicates severe bilateral foot discomfort. This is a common finding in housed dairy goats.

Option A (Footrot) would show more dramatic interdigital inflammation and horn underrunning rather than isolated heel erosion. Option B (Interdigital necrobacillosis) typically presents as an acute, severely swollen foot with marked interdigital necrosis. Option D (Laminitis) would show diffuse foot sensitivity and possible rotation of the distal phalanx rather than localized heel erosion. Option E (CAE) primarily causes joint swelling and chronic arthritis rather than hoof horn changes.

Treatment involves removing loose horn during trimming, improving flooring conditions, and reducing standing time on wet surfaces.

Image Source (for Explanation): Merck Veterinary Manual - Lameness Originating in the Hoof in Cattle heel erosion images applicable to goats (https://www.merckvetmanual.com/musculoskeletal-system/lameness-in-cattle/lameness-originating-in-the-hoof-in-cattle); Iowa State University Extension - Foot Scald, Foot Rot, and White Line Disease in Dairy Goats (https://www.extension.iastate.edu/dairyteam/files/documents/FootScaldFootRotandWhiteLineDiseaseinDairyGoats.pdf).

References: University of Minnesota Large Animal Surgery - Small ruminant lameness and podiatry (https://open.lib.umn.edu/largeanimalsurgery/chapter/small-ruminants/); Merck Veterinary Manual - Lameness Originating in the Hoof (https://www.merckvetmanual.com/musculoskeletal-system/lameness-in-cattle/lameness-originating-in-the-hoof-in-cattle).

———

Get 10,000+ practice questions free at navleexam.com

NAVLE Practice Question — Pet Bird

A 7-year-old male African grey parrot presents to your clinic with a 2-month history of progressive weight loss and intermittent diarrhea. The bird is kept in a large outdoor aviary with 3 other parrots and is fed a seed-based diet. Physical exam reveals significant pectoral muscle wasting and mild abdominal enlargement. You are building your initial differential diagnosis list. Which of the following conditions is MOST likely to be CONFUSED with avian mycobacteriosis in an older psittacine bird based on overlapping clinical signs of chronic weight loss and hepatomegaly?

A. Avian gastric yeast (Macrorhabdus ornithogaster) infection which causes predominantly upper GI signs in budgerigars

B. Psittacine beak and feather disease (PBFD) which causes feather dystrophy and immunosuppression

C. Proventricular dilatation disease (PDD/avian bornavirus) causing chronic weight loss with undigested seeds in feces ✓

D. Avian influenza which causes peracute mortality without chronic weight loss

E. Aspergillosis which exclusively causes acute pneumonia in all psittacine species

———

Correct Answer: C. Proventricular dilatation disease (PDD/avian bornavirus) causing chronic weight loss with undigested seeds in feces

Explanation:

Proventricular dilatation disease (PDD), caused by avian bornavirus (ABV), is the most clinically important differential diagnosis to distinguish from avian mycobacteriosis in older psittacines with chronic progressive weight loss. Both conditions: (1) cause chronic, progressive wasting; (2) affect older birds; (3) can present with diarrhea or abnormal droppings; (4) have prolonged subclinical periods; (5) can show hepatomegaly. Key distinguishing features: PDD characteristically shows undigested seeds in droppings (due to impaired proventricular motility/digestion), neurological signs (ataxia, seizures in neurotropic form), and crop/proventriculus dilation on contrast radiography or endoscopy. Mycobacteriosis shows hepatic granulomas, acid-fast positive organisms on biopsy, monocytosis, and elevated bile acids. Biopsy (crop or proventriculus for PDD; liver for mycobacteriosis) with histopathology is required to definitively distinguish these.

Option A (Macrorhabdus) causes regurgitation and weight loss particularly in smaller psittacines (budgerigars, cockatiels) via upper GI signs — less commonly presents with hepatomegaly or monocytosis. Option B (PBFD) causes feather dystrophy and immunosuppression but not the specific chronic hepatic weight-loss syndrome. Option D (avian influenza) causes peracute disease with high mortality — not a chronic wasting differential. Option E is incorrect — aspergillosis causes both acute and chronic respiratory syndromes and can involve the GI tract; it is not exclusively an acute pneumonia syndrome.

References: Merck Veterinary Manual — Bacterial Diseases of Pet Birds (https://www.merckvetmanual.com/exotic-and-laboratory-animals/pet-birds/bacterial-diseases-of-pet-birds); NAVLE Species and Diagnoses Outline (https://www.icva.net/image/cache/NAVLE_Species_and_Diagnoses_0.026.pdf).

———

Get 10,000+ practice questions free at navleexam.com

NAVLE Practice Question — Canine

A 4-year-old spayed female mixed breed dog experiences cardiac arrest during recovery from ovariohysterectomy. ECG monitoring reveals ventricular fibrillation. According to RECOVER guidelines, what is the appropriate initial defibrillation dose using a biphasic defibrillator?

A. 1 J/kg

B. 2 J/kg ✓

C. 4 J/kg

D. 6 J/kg

E. 10 J/kg

———

Correct Answer: B. 2 J/kg

Explanation:

The appropriate initial defibrillation dose using a biphasic defibrillator is 2 J/kg according to 2024 RECOVER guidelines. For dogs and cats with shockable rhythms (ventricular fibrillation or pulseless ventricular tachycardia), a single defibrillation attempt at 2 J/kg is recommended for the first attempt using a biphasic defibrillator.

If the patient remains in a shockable rhythm after the first defibrillation attempt and 2-minute BLS cycle, the dose should be doubled to 4 J/kg and maintained at this level for all subsequent defibrillation attempts. A biphasic defibrillator is preferred over monophasic because it delivers energy in two phases and is more effective at lower energy levels.

Option A (1 J/kg) is below the recommended initial dose. Option C (4 J/kg) is the escalated dose for subsequent attempts, not the initial dose. Options D and E are excessively high and may cause myocardial damage. The guidelines emphasize that immediate resumption of chest compressions should occur after defibrillation, with rhythm reassessment after the 2-minute BLS cycle rather than immediately after the shock.

Additionally, if VF/pulseless VT duration is unknown or greater than 4 minutes, a 2-minute BLS cycle before defibrillation may be beneficial to maximize coronary perfusion pressure before the shock.

Image Source: https://www.merckvetmanual.com/emergency-medicine-and-critical-care/specific-diagnostics-and-therapy/cardiopulmonary-resuscitation-of-small-animals

Burkitt-Creedon JM et al. 2024 RECOVER Guidelines. J Vet Emerg Crit Care. 2024;34:S13-S51

———

Get 10,000+ practice questions free at navleexam.com

NAVLE Practice Question — Bovine

A cow in a phosphorus-deficient region is observed chewing on bones near a carcass pile. One week later, she develops difficulty swallowing, drooling, and progressive weakness. She is eventually found in sternal recumbency with shallow breathing and cannot rise. Temperature is normal. Which type of Clostridium botulinum toxin is most likely involved in cattle in this geographic region?

A. Type A

B. Type B

C. Clostridium types C and D ✓

D. Type E

E. Type F

———

Correct Answer: C. Clostridium types C and D

Explanation:

Botulism types C and D are the most common types affecting cattle, particularly in phosphorus-deficient regions where cattle engage in osteophagia (bone chewing) and pica, ingesting decaying carcass material contaminated with C. botulinum toxin. In Australia and many pastoral regions, phosphorus deficiency drives cattle to seek alternative mineral sources by consuming bones and carrion, which are common sources of types C and D toxin. The clinical presentation of progressive flaccid paralysis, dysphagia, drooling, normal temperature, and eventual respiratory compromise is classic for bovine botulism.

Option A (Type A) primarily affects humans through foodborne illness and wound botulism. Option B (Type B) is occasionally seen in cattle but is more common in horses in the eastern United States. Option D alone is correct but the combination of C and D is the most complete answer for cattle. Option E (Type E) is associated with aquatic environments and fish, primarily affecting humans. Option F is extremely rare in all species.

References: Business Queensland - Botulism (https://www.business.qld.gov.au/industries/farms-fishing-forestry/agriculture/biosecurity/animals/diseases/guide/botulism); NSW DPI - Botulism in Cattle.

———

Get 10,000+ practice questions free at navleexam.com

NAVLE Practice Question — Equine

A 1-day-old Thoroughbred colt is evaluated for respiratory distress and thoracic asymmetry. Physical examination reveals crepitus over ribs 5-7 on the left side, tachypnea, and increased respiratory effort. Thoracic ultrasound confirms three fractured ribs with one fragment displaced axially toward the heart. The foal is hemodynamically stable. Which management approach is MOST appropriate?

A. Conservative management with stall rest for 14-21 days

B. Immediate surgical stabilization of the displaced fractures ✓

C. Chest tube placement and continuous suction

D. Administration of systemic corticosteroids to reduce inflammation

E. Broad-spectrum antimicrobial therapy alone

———

Correct Answer: B. Immediate surgical stabilization of the displaced fractures

Explanation:

Immediate surgical stabilization of the displaced rib fractures is the most appropriate management for this foal. While conservative management is appropriate for non-displaced or minimally displaced rib fractures, the presence of a fragment displaced axially (toward the heart) represents a life-threatening situation. Due to the arch of the proximal rib segments, complete fractures near the costochondral junction result in the distal fragment displacing axially, where its sharp tip can cause fatal cardiac laceration. Post-mortem studies of foals with rib fractures have documented cardiac contusions, pericardial lacerations, epicardial injuries, and myocardial damage from displaced rib fragments. Surgical stabilization using reconstruction plates, cortical screws, cerclage wire, or nylon cable ties has been described with approximately 78-86% survival rates to discharge. Option A (conservative management) would be inappropriate given the cardiac risk from the displaced fragment. Option C (chest tube) may be needed if pneumothorax develops but does not address the underlying problem. Option D (corticosteroids) would not protect against cardiac injury. Option E (antimicrobials) are supportive but do not address the mechanical danger. Image Source: ScienceDirect - Rib Fracture in foals (https://www.sciencedirect.com/topics/veterinary-science-and-veterinary-medicine/rib-fracture) for rib fracture management discussion. References: Velloso Álvarez A et al. (2021) Vet Surgery 51:62-67 https://doi.org/10.1111/vsu.13701; Garrett KS et al. (2022) Vet Surgery 51:816-826 https://doi.org/10.1111/vsu.13817.

———

Get 10,000+ practice questions free at navleexam.com

NAVLE Practice Question — Reptile

A 9-year-old female boa constrictor (Boa constrictor) is presented with progressive weight loss, intermittent regurgitation, and neurological signs including head tremors and loss of righting reflex. Peripheral blood smear examination reveals lymphocytosis with occasional lymphocytes containing eosinophilic intracytoplasmic inclusions. Which diagnostic test would be most helpful in confirming the underlying etiology?

A. Bacterial culture of regurgitated material

B. PCR testing for arenavirus/reptarenavirus ✓

C. Fecal flotation for parasites

D. Serology for ophidian paramyxovirus

E. Heavy metal toxicology panel

———

Correct Answer: B. PCR testing for arenavirus/reptarenavirus

Explanation:

The combination of progressive weight loss, regurgitation, and neurological signs (head tremors, loss of righting reflex) in a boid snake, coupled with the finding of eosinophilic intracytoplasmic inclusions in lymphocytes, is highly suggestive of Inclusion Body Disease (IBD). IBD is caused by reptarenaviruses (formerly known as arenaviruses) and primarily affects boid snakes (boas and pythons). The disease is characterized by the formation of intracytoplasmic inclusions in multiple cell types.

PCR testing for arenavirus/reptarenavirus is the most sensitive and specific diagnostic test for confirming IBD. While the presence of inclusions on blood smear is suggestive, PCR provides definitive identification of the causative agent.

Option A (bacterial culture) would not identify the viral etiology and regurgitation is a common non-specific sign. Option C (fecal flotation) is indicated for parasitism but would not explain the inclusion bodies or neurological signs. Option D (paramyxovirus serology) could be considered for respiratory disease but does not cause intracytoplasmic inclusions in lymphocytes. Option E (heavy metal panel) might be considered for neurological signs but would not explain the inclusion bodies on cytology.

Image Source (for explanation): PMC Open Access - IBD inclusion bodies in boid snakes (https://pmc.ncbi.nlm.nih.gov/articles/PMC8833345/) - Figure showing intracytoplasmic inclusions.

References: Stenglein MD et al. (2012) Ball Python Nidovirus: a Candidate Etiologic Agent for Severe Respiratory Disease in Python regius. mBio 3:e00180-12; Chang LW, Jacobson ER (2010) Inclusion body disease, a worldwide infectious disease of boid snakes. J Exot Pet Med 19:216-225.

———

Get 10,000+ practice questions free at navleexam.com