ICVA NAVLE Exam Questions

Correct answer: The same as a cat without FeLV exposure

The feline leukemia virus has a complex pathogenesis. We can see several states associated with infection.

1. Abortive infection occurs mostly via the oronasal route. Some immunocompetent cats mount sufficient cell-mediated and humoral immunity to prevent the development of viremia. These cats will have high detectable levels of neutralizing antibodies. Still, they will fail to detect positive viral RNA or proviral DNA in the blood. For several years, though not likely a lifetime, they will have protective immunity against reinfection. Their life expectancy is no different than a cat who has never had/been exposed to the virus. Further, they have no increased risk of cancer development. 
2. Regressive infection develops when animals mount a sufficient immune response, containing viremia before or just after it reaches the bone marrow. FeLV will spread via the lymphocytes and monocytes throughout the body. At this time, they will be shedding virus and they will be positive on an ELISA antigen test. Some cats may be asymptomatic, while others may show fever, enlarged lymph nodes, and lethargy. For the majority of patients, the viremia will last a few weeks as the virus travels to the thymus, spleen, salivary glands, and lymph nodes. Some of these cats will remain antigen positive. In contrast, others may never show positive on an antigen test, thus, complicating FeLV diagnosis. Some of these patients will develop high levels of viremia after replication in the bone marrow. Still, even some of these cats can clear the viremia in time. They will remain proviral DNA Positive because the DNA remains in the bone marrow. Still, they have a regressive (once called latent) form of the disease. Once this stage is reached, these cats will test negative on ELISA and IFA (antigen testing formats). Infection may reactivate with high-dose steroids or other immunosuppressive conditions, including during pregnancy, causing clinical disease in kittens. The closer to the viremic state a stressor occurs, the more likely the disease will reactivate. How often this type of infection can lead to active FeLV disease is unclear.
3. Progressive infection causes severe viral replication at the time of infection with mucosal and glandular viral shedding that will persist for life. These cats will have low levels of neutralizing antibodies. They often develop fatal FeLV-associated clinical disease. Most commonly, this is seen in young and immunosuppressed patients. 

Correct answer: Escherichia coli; failure of passive transfer

Neonatal septicemia in cattle is most commonly seen in the first two to seven days of life, though it can happen up to two to three weeks after birth. The intestinal mucosa becomes compromised by enteric bacterial colonization and subsequent infection or from another source where infection has arisen, such as a septic joint. However, these animals cannot fully protect themselves and become systemically sick because of a failure of passive transfer. Cattle require colostrum to obtain needed gammaglobulins, as they are born without them due to the complete separation of the maternal and fetal blood supplies. Thus, without this immune protection, they are highly susceptible to invasion by an array of organisms.

Neonatal septicemia, the third most common cause of calf deaths in the U.S., occurs most frequently in cattle with Failure of Passive Transfer (FPT). E. coli accounts for the majority of isolated bacteria. However, Salmonella spp., Campylobacter, Klebsiella, and others have also been identified in cases.

Signs of neonatal septicemia can include the loss or lack of a suckle reflex, fever (or low temp), scleral injection, depression, hypopyon, hyperesthesia, congested mucus membranes, increased capillary refill time, and signs of systemic illness. It is rapidly progressive and fatal without intervention. Animals will become tachycardic and eventually tachypneic. Hypotension and signs associated with decreased/poor cardiac output are likely. Some animals, when terminal, may develop diarrhea, but not all.  

Septic arthritis could provide a source leading to systemic sepsis. It may trigger infection, but FPT is the primary underlying cause, with E. coli as the most common species.

Meconium impaction may predispose to infection or illness. Still, it is unlikely to contribute to neonatal septicemia cases in the face of normal colostrum ingestion. 

Correct answer: Intralipids

Most patients with marijuana intoxication require no treatment — simply rest, minimal stimulation, and supportive care. They need to be removed from exposure and not reintroduced into it. Depending on the severity and degree of debilitation, they may require heat support, IV Fluid therapy, or even nutritional support (though most of these patients, if they are in control of the respiratory system, will eat). Seizure activity, if it develops, can be controlled with benzodiazepines. With marijuana products, intralipids usually aren’t required. However, in severe life-threatening intoxications, we can use intralipids (a fat sponge, so to speak), which can help absorb/bind the THC and improve outcomes. However, intralipids are not without risks and should only be used in life-threatening intoxications. 

Correct answer: Vesicular stomatitis; prohibit new animals from entering the premises and instruct humans in contact with the animals to wear proper protective clothing

Vesicular stomatitis viruses are zoonotic, with the potential to cause flu-like signs in people, including headache, weakness, and muscle pain. Signs last 3-5 days, and most reported human cases occur in laboratory workers working very closely with the organism and lesions. Humans rarely get actual vesicles and encephalitis.

Rhabdoviridae family viruses, genus Veisiculovirus, cause vesicular stomatitis. New Jersey and Indiana are two serotypes of concern in the Western hemisphere. We do see it occasionally in the U.S., primarily in the West. Transmission occurs through direct contact or via blood-feeding insects. The primary vector in the U.S. is the black fly (Simulidae), while in endemic areas, the sand flies (Lutzomyia) generally transmit the disease. The disease incubates for 2-8 days and then leads to a fever, though this usually has resolved by the time outward clinical signs are evident. Pigs, goats, sheep, cattle, camelid species, and horses are all susceptible, though clinical signs vary slightly from one species to another. Oral vesicles, ulcers, erosions, and further lesions on the tongue, teats, and coronary bands may occur. Cattle may develop secondary mastitis. However, the disease is generally self-limiting and resolves without intervention in 10-14 days.

Treatment is supportive, including softening food, managing any secondary bacterial infections associated with lesions, and addressing management concerns. This includes proper quarantine of new animals entering the herd, and insect control measures, including providing proper shelters and insect repellents in areas where black flies typically feed, e.g., the inner surface of the pinna.

All affected animals should be isolated, and animal movement should be prevented until all issues are resolved.

Veterinarians are required to report this disease. While it is self-limiting and not a cause for depopulation or other extreme measures, because of its similarity to other conditions which cause vesicles, such as foot and mouth disease, it is paramount to ensure reporting occurs promptly and diagnosis is confirmed. Education of owners must include prevention measures and biosecurity protocols.

Foot and mouth disease, a reportable disease because of how contagious it is and with concerns about bioterrorism applications, is an aphthovirus from the Picornaviridae family. Generally, this affects those with cloven hoofs — it doesn't affect horses, dogs, or cats. Clinical signs may include fever, and vesicles on the teats, feet, muzzles, and mouth. Direct contact, as well as aerosolization, transmit this highly contagious disease. While not zoonotic, like vesicular stomatitis, it is generally fatal, though eradicated in North America and Western Europe.

Correct answer: Tobramycin

No medications are actually labeled for use for the treatment of otitis media. Care must be used when the tympanum cannot be seen and/or is opaque, suggestive of a middle ear infection, or CT confirms this. Deafness may result from various medications.

The safest infusion medications for the ear would be aqueous solutions of ciprofloxacin, marbofloxacin, or enrofloxacin (fluoroquinolones). Additionally, aqueous gentamicin, an aminoglycoside, is considered safe. However, others, like tobramycin, have been associated with severe hearing loss. Further, the semisynthetic penicillin, ticarcillin, has caused deafness. The antifungals are generally safe and include miconazole, nystatin, clotrimazole, and tolnaftate. However, short-term deafness has been seen with clotrimazole or miconazole that resolves with cessation of the medication.

Often, when the eardrum is either absent or not visible (due to stenosis or severe debris), starting with an aqueous solution mixed with a fluoroquinolone +/- a steroid +/- an antifungal mixed in gets therapy going. A different formulation may be feasible once the eardrum is readily visible and the ear begins to heal.

Correct answer: Defensive body position

Technically, all of the answers above can be considered normal cat behaviors. They may occur when stressed or frightened and do not always mean the cat is being aggressive. They may be behaviors that have been reinforced without owners even realizing it. However, a cat simply taking a defensive body posture doesn't mean that the cat is about to be or being aggressive. It is a natural self-defense behavior and response.

Aggressive behaviors can occur as a response to fear, misdirected or inappropriate play aggression, petting-induced or handling-associated aggression, redirected aggression, and aggression secondary to underlying medical conditions, including pain.

Animals that do show signs of aggression may hiss, bite, scratch, or attack. 

Correct answer: Heart

The clinical signs above, the presence of green urates, non-pathognomonic findings on necropsy, and the species should give you clinical suspicion for an infectious cause. You suspect Pacheco's disease, which is a psittacine alpha herpesvirus. In New World species such as this macaw, we can see viral hepatitis. In animals who do not succumb to disease, they will develop internal papillomatosis, most commonly seen in macaws, Amazon parrots, hawk-headed parrots, and conures. Birds can be asymptomatic carriers, shedding virus to those who are uninfected. For birds that are then stressed, as is commonly seen with other species and herpesviruses (cats, people), the disease can flare up.

Transmission occurs by the fecal-oral route, aerosol, or direct contact. Outcomes vary with the virus genotype, the bird's overall health status, and the species infected.

Once infected, even if clinical signs resolve, birds will be forever carriers and persistently yet intermittently shed for life.

Clinical signs include sudden death with normal body condition, bright yellow urates, and minimal feces. However, this can be preceded by green urates, lethargy, weakness, depression, regurgitation, or diarrhea.

For the birds the owner has at home, a DNA probe combining both oral and cloacal swabs can be used. Bloodwork may show leukopenia and elevated AST.

Intranuclear inclusions are histologically evident in the pancreas, spleen, liver, and intestinal epithelium, not the heart.

Treatment consists of supportive care. Acyclovir has been used as well, but each time a bird is handled and stressed, this increases the risk of transmission. An inactivated vaccine or autogenous vaccine can be used.

If birds develop papillomatosis, these lesions predominate in the oral and cloacal mucosa, but may be internal as well (GI tract, bursa, or conjunctiva). Sometimes owners fear a cloacal prolapse when part of the papilloma is peaking out of the vent. Treatment at this stage is supportive, and if lesions are bleeding/ulcerative, treating any secondary infections that arise may be needed.

Correct answer: All antibiotics are extra-label use in camelids

You will need to discuss the use of medications with your client. Explain that the FDA has not yet approved medications for use in the species but permits extra-label use when appropriate to treat infections and other disease states. These medications cannot be used to enhance performance or for weight gain for any species.

Amoxicillin is not approved in camelids, sheep, or goats and is used off-label in these species. Penicillin G (procaine) and Tilmicosin are approved for use in sheep by prescription only. 

Correct answer: Molecular detection of the viral spike (S1) gene

IBV is a worldwide avian coronaviral disease, with chickens as the primary host, though the disease has been seen in peafowl and pheasants. It is transmitted via inhalation and direct contact, and morbidity in birds is usually 100%. Various strains lead to different clinical pictures, including decreased egg yields, poor egg quality, upper respiratory tract disease, andacute nephritis. Respiratory lesions are not granulomatous but may contain serous, caseous, or catarrhal exudates when advanced and are foamy within the air sacs, then develop cloudiness as the disease progresses. 

The preferred diagnostic test molecularly detects the viral spike (S1) gene. Once the S1 gene is identified, a lab can further perform sequence analysis to define the serotype. This is time-consuming and costly. 

Less expensive methods of identification, without identifying the serovar-specific strain, include Reverse Transcriptase Polymerase Chain Reaction (RT-PCR), assessment of rising antibody titers against IBV preclinical to convalescent sera, or virus isolation in embryonated eggs.

If you are collecting samples from a large flock, be sure to collect samples from animals with and without clinical signs. Signs generally develop three to five days post-infection, when peak titer is no longer evident. 

Correct answer: Phosphate-restricted diet

The best way at this stage to address phosphorus is by restricting intestinal phosphate absorption. This is most easily done via phosphate-restricted diets, which is accomplished by feeding a lower-protein, low-phosphorus diet. The IRIS staging helps provide target-specific phosphorus levels to shoot for and ways to control it. But be mindful that the body may take time to adjust total phosphorus levels because of whole-body phosphate retention. It may take two to four weeks for plasma phosphate concentrations to truly reflect the disease state. If cats at this stage of the disease won't take to the renal diets (low phosphate foods), a phosphate binder may need to be started sooner rather than later. 

Correct answer: Laryngospasm

A protective reflex, laryngospasm, occurs, causing the laryngeal cartilages to rapidly close, spasm, and flutter. It can be triggered by irritants such as anesthetic gasses or positive continuous airway pressure. We commonly see it in veterinary medicine when trying to plate an endotracheal tube in cats more commonly than dogs. It can occur if the patient isn’t fully anesthetized while trying to intubate and or you are forcing intubation. Brachycephalic dogs may be at increased risk.

Conversely, reverse sneezing is paroxysmal sneezing that occurs as a forceful, inspiratory airflow. It is most commonly in response to allergic or mechanical irritation to the nasopharynx or posterior nasal cavity. When occurring, animals hold their heads normally or have them thrust back some. It sounds like the dog is inhaling a sneeze, hence the name. It can last seconds to minutes. Basically, it is a spasm. The dog may extend the neck and expand the chest to inhale harder.

Causes include anything irritating the throat, though no obvious inciting cause is often readily evident. Things like excitement (especially in brachycephalic breeds), drinking (especially too fast), eating, leash pulling, pollen, and foreign bodies that get caught in the throat, like grass awns, grass, or related items. Further, irritants like household chemicals (think bleach), perfumes, some viruses, and even simple post-nasal drip from an upper respiratory or lower respiratory tract infection. Brachycephalic breeds or others with elongated soft palates may inadvertently trap it in the throat and trigger an episode.

Usually, it is a minor issue, though scary for dogs and pet owners. If it becomes a chronic problem, there could be something stuck in the nasal passage or a mass or other problem, and scoping may be warranted.

Cats rarely develop this condition. However,  a consideration to think of if a cat presents with this would be feline asthma. That “sneeze” may really be a cough that the owner misinterprets as a sneeze/reverse sneeze or truly is a reverse sneeze. 

Correct answer: Once the object has been snared, pull out against undue resistance

For foreign body removal, each patient is different, and each procedure is different. However, a few basic principles should always be followed regardless of the patient:

1. Ensure you re-radiograph before inducing to ensure the foreign material hasn’t moved aborad. It is now out of reach of the scope or hasn’t caused perforation or other abnormalities. 
2. Don’t just grab and pull. Often, the object needs to be repositioned, permitting the forceps to get the best grasp on it. Further, one may need to reposition it to ensure it is easily removable through the sphincters. 
3. Select appropriate instruments. Use retrieval forceps that permit the firmest grasp. 
4. Once an object has been snared, do NOT pull against undue resistance. We expect high resistance associated with the lower esophageal high-pressure zone, in the gastric cardia, at the base of the heart, the cricopharyngeal area, and the thoracic inlet. If too much resistance is appreciated, stop, reorient the object if needed, and begin again. You may even need to release it and re-grab or use hoods or overtubes to assist. 
5. Overtubes can be used when sharp or irregular edges are present or to help you dilate the lower esophageal sphincter.

Correct answer: Are soil magnesium levels low in the area?

Remember, these are nursing calves, though they are being bottle-fed. These neurological signs and related issues suggest a toxin, like an insecticide or salt toxicity. Salt intoxication manifests when there is limited access to fresh water either because of overcrowding, weather issues, mechanical issues, or the freshwater available is brackish. Salt lick blocks can contribute. Softened water can be higher in salt and shouldn't be used to mix milk replacers until checked to ensure that concentrations fall below 100 ppm. Dehydration and hot weather can also increase the risk of intoxication.

Differentials for these animals include carbamate or organophosphate toxicity. Thus, knowing if these products were used near/around the calves is important. Other causes may include polioencephalomalacia, lead poisoning, rabies, or staggers (hypomagnesemic tetany). Animals not on pasture and with properly formulated milk shouldn't have issues with low magnesium levels. Whether the pasture has magnesium is irrelevant since they are currently bottle-fed, and their nutrition source is milk.

Correct answer: Atropine (+/- Pralidoxime chloride (2-PAM))

Based on clinical signs, you presume the toxin to be either an organophosphate or a carbamate product. Ideally, 2-PAM and atropine would be administered in the face of organophosphate intoxication. However, since we do not yet know if it is an organophosphate or carbamate product, we will start with atropine. Both of these are commonly used as pesticides and insecticides. They work by binding irreversibly (organophosphates) or reversibly (carbamates) to acetylcholinesterase within the muscles and tissues of the nervous system. This allows acetylcholine to build up, causing continuous stimulation (cholinergic). As a result, it causes overstimulation of various synapses, including the central, nicotinic, and muscarinic, accounting for the wide array of clinical signs.

The parasympathetic signs we see are based on the acronym SLUDGE. This refers to Salivation, Lacrimation, Urination, Defecation (diarrhea), GI distress, and Emesis that occur as a result. These are reversible with atropine sulfate (controlling the parasympathetic side effects). Titration and dosing should occur until the pupils are sufficiently dilated, salivation stops, and the patient is more with it. This medication doesn’t address those side effects related to the cholinergic nicotinic impact, such as muscle tremors/fasciculations or paralysis.

Glycopyrrolate is also an anticholinergic/antimuscarinic-like atropine. However, it doesn’t cross the blood-brain barrier and has a slower onset of action than atropine, though it does last longer. It is an alternative if atropine is not available, but generally, protocols against these toxins utilize atropine over glycopyrrolate.

2-PAM is an antidote for organophosphate toxicity, acting as a cholinesterase reactivator. It must be administered within 24–36 hours to be effective. It is not recommended for carbamate poisonings, so you may want to withhold it until the owner contacts the company to determine the product used. That being said, sometimes products can be a mixture of organophosphates and carbamates, and so, if the owner will not be able to get a hold of the company for 24+ hours, then it may be reasonable to presume that it includes an organophosphate and give the medication since delay can worsen prognosis.

Activated charcoal is being used less in less by ASPCA poison control. Depending on the degree of exposure and route (topical, dermal vs. oral ingestion), this may depend on additional therapies recommended for this patient. Removing them from the source is important. But activated charcoal will not address any of the potentially life-threatening issues. It will not treat any of the clinical signs. It can be considered once the pet is stable, not vomiting, and alert enough. Contact poison control if in doubt. Since we know this patient’s exposure was within a short time frame, it may be warranted once stable.

Correct answer: What happens immediately after the behavior ceases?

The ABCs of behavior refer to the antecedents, behaviors, and consequences.

Antecedents may be environmental triggers or owner-initiated behaviors that trigger the event. 

1. Was there suddenly a loud crashing sound? 
2. Does it only happen at night when the owner is getting ready for bed? 
3. Was the animal sleeping right before the behavior started or pacing? Was it vocalizing? 
4. Was the animal just fighting with another pet in the house?

"B" refers to what the behavior itself is, and "C" refers to what happens directly after the behavior ceases, and what consequences if any occur as a result of the behavior (i.e., does the owner give the cat love and affection or scream and yell at it?).

Correct answer: Right oculomotor nerve (III)

Pupillary constriction occurs via the oculomotor nerve (III). Since the PLR is missing on the right eye but present when light is shone into the right eye on the left (indirect PLR), and directly, with light directly into the left eye, the lesion appears to be affecting the third cranial nerve on the right, the oculomotor nerve.

Cranial nerve II (optic nerve) is the afferent arm for the PLR and vision, which results in sensory transmission to the brain. Alternatively, cranial nerve III, or the oculomotor nerve, makes up the efferent arm of the PLR while also innervating many of the periocular muscles. Recall that afferent neurons carry information toward the CNS, while efferents carry info to the periphery (away from the CNS).

Correct answer: 1% to as little as 0.1% of the number is needed to infect immunocompetent animals

There are no host-adapted Salmonella species identified in horses. However, salmonellosis in our equine patients is commonplace and the most common infectious cause of diarrhea in horses. It can be a serious disease with variable morbidity and high mortality rates that varies with each Salmonella species. Acutely infected animals shed large bacterial loads in the feces through diarrhea, though not all clinical forms will have diarrhea.

The most common form of salmonellosis in equines presents with acute colitis, colic, and profuse diarrhea. Often, rapidly, these horses become septic with a high risk of vascular leak syndrome, coagulopathies, and cardiovascular shock. Animals often have signs consistent with shock/sepsis, including elevated heart rates, commonly febrile, and may be obtunded. They are usually very dehydrated. Another syndrome may develop in the absence of diarrhea where animals are leukopenic, febrile, show signs of colic, and have significant gastric reflux secondary to proximal enteritis.

The infective dose required for immunocompromised horses is much lower than that for the competent horse, with ranges of 0.1–1% of the infective dose necessary to cause clinical disease. This means that isolation of affected horses is paramount as part of infection control and prevention protocols for any infected farm. 

Correct answer: The Fair Labor Standards Act

The Fair Labor Standards Act establishes set wages and overtime pay, administered by the Wage and Hour Division of the Department of Labor. Nonexempt employees must be paid at least minimum wage and anything considered overtime at a minimum of time and a half.

The Occupational and Safety and Health (OSH) Act refers to workplace safety in the majority of industries; compliance is required pertaining to various safety and health standards and helps to ensure protection from serious hazards.

Labor-Management Reporting and Disclosure Act (Landrum-Griffin Act) has to do with labor union protections.

Consumer Credit Protection Act provides help to protect an employee's wages from garnishment for debt to a certain degree per week. It applies to all workers exempt and nonexempt, and those with wages or salaries and other types of compensation, usually excluding tips.

Correct answer: Atelectasis from chronic asthma

This patient’s radiographs show chronic evidence of asthma. Atelectasis or lung collapse can occur due to asthma. The pulmonary pattern shown here is a diffuse, moderate broncho-interstitial pattern with suspected mucous plugs. The cat’s chronic cough has been causing more problems for the pet than the owners have appreciated.

There is no evidence of metastatic or nodular disease.

Common reasons for atelectasis in the cat include asthma or Pulmonary Thromboembolism (PTE). Atelectasis most commonly occurs in the right middle lung lobe. It happens due to the accumulation of mucus within the bronchus. Patients with pulmonary thromboembolism often have significant clinical signs, including dyspnea, tachypnea, and depression. It is unlikely to be an incidental finding, as atelectasis can be in asthmatic cats.

The pulmonary pattern here most closely resembles asthma or bronchitis (chronic in nature) though atypical pneumonia cannot fully be ruled out. Often, animals with PTE have normal radiographs or non-diagnostic changes. However, given the history of coughing for years, the lack of respiratory signs, and the presumptive mucus plugs, chronic asthma is the most likely cause. 

Correct answer: 2 mL/kg

Ethylene glycol intoxications are uncommon in livestock. However, it can be found in antifreeze, transmission/brake fluids, and de-icer products. The producer admits that a vehicle broke down and had to replace the brake fluid. They couldn’t get the vehicle moved for 48 hours because of a storm that came through, and they then had to use a de-icer to gain entry because everything had frozen solid. Though they hadn’t appreciated any chemical spills, you suspect that is what happened. The producer didn’t realize the product was toxic, providing a great opportunity for education and discussing farm security and management improvements.

Prognosis is better for animals who ruminate than those who do not; thus, a smaller dose is required to cause clinical disease for young calves not yet ruminating. They have a worse prognosis, even with treatment. For non-ruminating calves, the toxic dose is 2 mL/kg, while for adult cattle/ruminating animals, it is 5–10 mL/kg.