Sample Questions NAVLE DrPaMoEs Flashcards

1
Q

Which of the following statements is true about pinworm infections in mice?
There is no good treatment for pinworms in
mice
Infections always result in diarrhea
The worms inhabit the descending colon in mice
Heavy parasite loads may lead to rectal prolapse

A

Answer: Heavy parasite loads may lead to rectal prolapse

The correct answer is heavy parasite loads may lead to rectal prolapse. Pinworms (Syphacia obvelata and Aspicularis tetraptera) in mice inhabit the cecum. Most infections are subclinical and treatment involves administration of piperazine sulfate. Ivermectin may be used as well.

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2
Q

Most bladder stones in rabbits are primarily composed of?

  • Magnesium
  • Urate
  • Phosphorus
  • Cysteine
  • Calcium carbonate
A

Answer: Calcium carbonate

The correct answer is calcium carbonate, although there seem to be multiple causes of formation of cystic calculi. One major component is that rabbits will absorb calcium through their GI tract at a rate directly proportional to the amount of calcium in their diet regardless if they need it or not. Excess calcium is then excreted through the kidneys.

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3
Q

A 3 1/2 year old castrated male ferret presents for episodes of lethargy. He has also been intermittently dragging the pelvic limbs. Which of these choices is a likely cause of these signs in this ferret?
Insulinoma
Renal carcinoma
Adrenal tumor
Diabetes mellitus

A

Answer: Insulinoma

The correct answer is insulinoma. This condition is common in ferrets and would cause bouts of lethargy. Intermittent pelvic limb weakness is another manifestation of systemic weakness secondary to hypoglycemia. Renal carcinoma is not common in ferrets. Adrenal tumors and diabetes mellitus usually are accompanied by different clinical signs.

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4
Q

Which of the following diseases is not commonly associated with beak abnormalities?

  • Polyoma virus
  • Liver failure
  • Cnemidocoptes infestation
  • Psittacine beak and feather disease
A

Answer: Polyoma virus-

The correct answer is Polyoma virus. The virus usually results in lethargy, anorexia, depression, and death. The death may be acute in nature, and it is likely that there will be no beak abnormalities.

Whenever you observe beak abnormalities, you should rule out liver disease. Cnemidocoptes infestations lead to a honeycomb-like beak.

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5
Q

Broiler chickens often develop lesions that negatively impact welfare in which part of their bodies due to the rapid muscle growth that they experience?
Feet and legs
Reproductive organs
Comb
Breast muscle
Head

A

Answer: Feet and Legs

Rapid growth is associated with limb and foot
lesions in broilers.

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6
Q

A 20-year old mare is presented for a dermal nodule on her head. An aspirate of the mass reveals that it is a mast cell tumor. What is the prognosis for this horse?

  • Guarded, the tumors do not metastasize, but they are locally aggressive and are difficult to excise completely.
  • Grave, the tumor has already metastasized and the life expectancy of the horse is no longer than 1 month.
  • Good; the tumors are benign and excision is usually curative.
  • Poor, the tumors have often metastasized by the time they are diagnosed.
A

Answer: Good; the tumors are benign and excision is usually curative.

The correct answer is good; the tumors are benign and excision is usually curative. Mast cell tumors in horses are benign. They can occur anywhere on the horse, but are often found in the dermis or subcutis of the head or legs. The tumors may also invade underlying musculature, but are often walled off by aggregates of fibrous stroma.

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7
Q

A guinea pig presents to your emergency clinic for oral petechia and loose teeth. You also note a rough hair coat on physical exam. What nutritional disorder is common in guinea pigs and can lead to the signs described?

  • Hypovitaminosis D
  • Hypovitaminosis A
  • Hypocalcemia
  • Hypovitaminosis C
  • Hypervitaminosis A
A

Answer: Hypovitaminosis C

The correct answer is hypovitaminosis C. Guinea pigs are frequently deficient in vitamin C and can develop scurvy. Vitamin C is necessary for collagen synthesis, and deficiency leads to a rough hair coat, loose teeth, petechia, and lameness. It is treated with vitamin C injections, as multivitamins can lead to vitamin A and D toxicosis. Leafy green vegetables are good dietary sources of vitamin C.

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8
Q

An owner just arrived from a camping trip with his dog.
He is worried about his dog that seems to have undergone a change in behavior after being attacked by a wild animal. Additionally, the owner thinks that the dog’s voice has actually changed. What is your top differential?
Canine Distemper
Rabies
Botulism
Tetanus

A

Answer: Rabies

The correct answer is rabies. If it sounds like it could be rabies, diagnose it until proven otherwise.
The signs to focus on are attacked by a wild animal, a behavior change, and a voice change.
This should put rabies at the top of your list. This dog is exhibiting signs of the prodromal stage of rabies. Canine distemper is a potential differential, but you will most likely see other symptoms such as respiratory and Gl signs. Tetanus will manifest itself as rigidity and botulism as flaccid paralysis.
Remember that any animal with an acute behavioral change or flaccid paralysis is a rabies suspect.

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9
Q

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 are 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?
Trypanosoma evansi
Clostridium tetani
Methicillin-resistant Staphylococcus aureus
Rabies virus

A

Answer: Clostridium tetani

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.

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10
Q

A one year old rescued iguana presents for further evaluation as a result of poor growth. Survey radiographs show osteopenia and evidence of remodeling suggestive of a previous fracture. What is the most likely diagnosis?

  • Metabolic bone disease
  • Gout
  • Hypovitaminosis C
  • Primary hypoparathyroidism
A

Answer: Metabolic bone disease

The correct answer is metabolic bone disease.
Other things to look for are a pliable mandible and maxilla. Usually, you will see bowing of the long bones with rounding of the skull. The disease usually occurs as a result of secondary nutritional hyperparathyroidism or hypovitaminosis D.

Gout results from a primary overproduction of uric acid or an inability to excrete uric acid.

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11
Q

You and your hospital are interested in purchasing a $30,000 ultrasound machine. Which of the following factors will have the biggest influence on whether such a purchase will be profitable?

  • The interest rate on the loan for the purchase
  • Whether the machine is purchased vs. leased
  • Marketing and pricing
  • The cost of insuring the machine
A

Answer: Marketing and pricing

Determining whether to lease or purchase new equipment, current interest rates, and other costs are all very important considerations. However, the ability to make such a purchase profitable hinges on the ability to successfully market the product and services associated with it and the associated prices that will be charged.

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12
Q

A 2-year old MN DSH has recently been treated for a urethral obstruction. He went home last week from the hospital on an acidifying canned diet for this condition.
The owner reports he is passing urine in moderate amounts, but he is still straining frequently. You reexamine the cat and find that the bladder is empty on palpation and the wall feels a little thickened. You are confident that the cat has not re-blocked and the cat’s bloodwork shows normal electrolytes and renal values.
Which of the following medications may help the cat with this problem?

  • Amitriptyline
  • Phenoxybenzamine
  • Phenylpropanolamine
  • Methocarbamol
  • Prednisolone
A

Answer: Phenoxybenzamine

This cat is likely suffering from hypertonicity of urethral muscle, which was incited from the recent obstruction and urinary catheter. This can cause spasms, which makes urinating painful and not easily controlled. Phenoxybenzamine can be used in this case to reduce internal urethral sphincter tone such that the cat may urinate more easily.

Methocarbamol is a muscle relaxant but would not directly help spasms of the urethra.
Prednisolone is not used to help reduce inflammation or spasms in the urethra and may predispose the cat to contracting a urinary infection, especially while his bladder and urethra are compromised.

Pheny|propanolamine is used to treat urinary incontinence from urethral hypotonicity most often in dogs and would be contraindicated in this case.

Amitriptyline is an anti-depressant medication that has been implicated as part of a treatment plan for cats with cystitis, although benefit has never been proven. Because cats with cystitis can flare up during times of stress, the amitriyptyline has been thought to help prevent this. This medication would not work to stop spasms in the urethra.

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13
Q

A 2-year old MN DSH has recently been treated for a urethral obstruction. He went home last week from the hospital on an acidifying canned diet for this condition.
The owner reports he is passing urine in moderate amounts, but he is still straining frequently. You reexamine the cat and find that the bladder is empty on palpation and the wall feels a little thickened. You are confident that the cat has not re-blocked and the cat’s bloodwork shows normal electrolytes and renal values.
Which of the following medications may help the cat with this problem?
Amitriptyline
Phenoxybenzamine
Phenylpropanolamine
Methocarbamol
Prednisolone

A

Answer: Phenoxybenzamine

This cat is likely suffering from hypertonicity of urethral muscle, which was incited from the recent obstruction and urinary catheter. This can cause spasms, which makes urinating painful and not easily controlled. Phenoxybenzamine can be used in this case to reduce internal urethral sphincter tone such that the cat may urinate more easily.
Methocarbamol is a muscle relaxant but would not directly help spasms of the urethra.
Prednisolone is not used to help reduce inflammation or spasms in the urethra and may predispose the cat to contracting a urinary infection, especially while his bladder and urethra are compromised.
Pheny|propanolamine is used to treat urinary incontinence from urethral hypotonicity most often in dogs and would be contraindicated in this case.
Amitriptyline is an anti-depressant medication that has been implicated as part of a treatment plan for cats with cystitis, although benefit has never been proven. Because cats with cystitis can flare up during times of stress, the amitriyptyline has been thought to help prevent this. This medication would not work to stop spasms in the urethra.

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14
Q

Which of the following is an appropriate objective in the repair of an articular fracture in a dog?

  • 6-8 weeks of strict post-operative rest
  • Early return to function
  • Avoid rigid fixation of the fracture
  • 50% or greater alignment
A

Answer: Early return to function

The correct answer is early return to function.

With articular fractures, the 3 major goals of the clinician are:
1) Rigid fixation of the fracture fragments; neglecting to do this will result in loose fracture fragments within the joints that will promote osteoarthritis.
2) Anatomic realignment (50% or even 75% is not adequate with articular fractures, in contrast to long bone fractures)
3) Early return to function. With long bone fractures, extended rest is recommended to promote stability and healing of the bone. The opposite is true in articular fractures where prolonged rest after repair will promote fibrosis, causing decreased range of motion in the joint.

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15
Q

An obese, sedentary, female Bichon Frise of 5 months of age walks into your clinic as a result of having mucus-laden diarrhea of one-week duration. You perform a gram stain of the feces and visualize “gull-shaped” gram-negative rods. What is the most likely diagnosis?

  • Salmonellosis
  • Cryptosporidium
  • Campylobacteriosis
  • Clostridioides difficile
A

Answer: Campylobacteriosis

The correct answer is Campylobacteriosis. This is a gram negative motile, thin, S-shaped or gull-shaped rod. It can occur singly, in pairs, or in chains. C. jejuni is most commonly isolated. You can also isolate this organism with fresh fecal swabs streaked onto Campylobacter blood agar plates, which grows in an oxygen-reduced atmosphere in 3-4 days.

Salmonella is a gram-negative bacillus. C. difficile is a gram-positive rod.

Cryptosporidium is a coccidian parasite. Fun Fact:
Kids with puppies are 16 times more likely to acquire Campylobacteriosis.

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16
Q

What is the duration of a mare’s estrous cycle?

  • 9-15 days
  • 19-26 days
  • 41-52 days
  • 27-37 days
  • 53-60 days
A

Answer: 19-26 days

The correct answer is 19-26 days. Estrus in a mare can last 2-10 days but, on average, is 6 days long.

The mare is a polyestrous animal from the beginning of spring through summer. The estrous cycle’s duration lasts 19-26 days.

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17
Q

A 6-year old West Highland White Terrier comes in to see you for the mucopurulent ocular discharge as seen in the photo below. A Schirmer tear test shows no tear production. What is the treatment of choice for chronic canine keratoconjunctivitis sicca?

A. Systemic cyclosporine and antibiotics
B. Systemic antibiotics and corticosteroids
C. Topical cyclosporine and systemic corticosteroids
D. Topical cyclosporine and a topical steroid

A

Answer: Topical cyclosporine and a topical corticosteroid

The correct answer is topical cyclosporine and a topical steroid. The treatment of KCS is aimed at reducing immune destruction of the lacrimal glands.

Topical cyclosporine (Optimmune) and a topical steroid (frequently in a triple antibiotic/steroid ointment) are the treatment of choice. You should be cautious using steroids in acute cases due to the risk of corneal ulceration.

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18
Q

Zoonotic diseases commonly carried by raccoons include rabies and

  • Toxocara
  • Baylisascaris
  • Echinococcus
  • Trichinella
A

Answer: Baylisascaris

The correct answer is Baylisascaris.

Baylisascaris procyonis is an ascarid parasite of raccoons that causes mild signs in raccoons but can undergo aberrant migration in humans and cause fatal central nervous system signs.

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19
Q

Which of the following can be treated with enalapril?

  • Acute renal failure
  • Hypotension
  • Protein-losing nephropathy
  • Protein losing enteropathy
A

Answer: Protein-losing nephropathy

Enalapril is an angiotensin-converting enzyme
(ACE) inhibitor used as a vasodilator, antihypertensive agent, and heart failure treatment. It works by preventing the conversion of angiotensin I to angiotensin Il, thus reducing aldosterone concentrations and causing diuresis.
Its dilatory effects on the efferent arterioles of glomeruli help to palliate protein losing nephropathies. It is often used in conjunction with diuretics.

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20
Q

A 3-year old indoor/outdoor domestic short hair cat presents with a history of lethargy and decreased appetite. T= 103.1 F/ 39.5 C, P= 200 bpm, R= 36. On exam you note a swelling over the bridge of the nose and on fundic exam see some dark circular lesions in the retinas. The disease you suspect in this cat may have been transmitted by which of the following?

  • Puncture wound from contaminated soil
  • Scratch from another cat
  • Ingestion of oocyts from raw meat
  • Inhalation of spores from pigeon droppings
A

Answer: Inhalation of spores from pigeon droppings

Cryptococcus is a genus of encapsulated yeast that is often associated with or found in pigeon droppings and eucalyptus trees. The spores are most often inhaled from the environment where these are present. Cats with cryptococcus will often develop a swelling over the bridge of the nose and lesions in the retinas.

Sporothrix is a fungus found in the soil (“rose grower’s disease”) and is introduced into the body via a puncture from a thorn or through an open wound or cut when exposed to contaminated soil.

Toxoplasmosis may be transmitted through ingestion of raw meat.

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21
Q

A 10-year old female spayed boxer presented for a mass on the left side of the neck. The mass was diagnosed as a mast cell tumor based on fine needle aspirate. Screening with thoracic radiographs, abdominal ultrasound and bloodwork was unremarkable. The owners elected for surgical removal and clean 3 cm margins were obtained in all directions. The mass was submitted for histopathology and was categorized as a grade 3 (or high grade) tumor. What is your recommendation to the owner?

  • Start a doxorubicin based chemotherapy protocol.
  • Start a tyrosine kinase inhibitor chemotherapy drug.
  • Monitor the surgical site for recurrence; abdominal ultrasounds every 3-4 months.
  • Radiation therapy for the surgical site and prescapular lymph node; abdominal ultrasounds every 3-4 months.
A

Answer: Start a tyrosine kinase inhibitor chemotherapy

Under the Patnaik grading system, grade 3 tumors are highly metastatic.

Mast cell tumors are highly responsive to radiation therapy, but with clean excision and wide surgical margins, local recurrence is unlikely. Metastasis is the primary concern and a wait and monitor approach is not advised.

Even with no evidence of metastasis at the time of surgery, chemotherapy should be initiated as soon as possible.

Common protocols include single agent or alternating vinblastine and lomustine. Tyrosine kinase inhibitors, such as toceranib (Palladia) and masitinib (Kinavet, which is no longer available), target c-kit, a stem cell factor receptor involved in mast cell proliferation and differentiation.

Palladia and Kinavet are FDA approved for treatment of high-grade canine cutaneous mast cell tumors.

22
Q

Ensuring that animals have a place to go so that they are no longer being viewed by humans is a strategy employed by which types of facilities to help promote good animal behavior?

Zoos

Poultry farms
Veterinary schools
Feedlots
Research laboratories

A

Answer: Zoos

Providing proper areas for seclusion and rest away from visitors can reduce the incidence of stereotypies in zoo animals.

23
Q

Which of the following is a common cause for diarrhea in growing and finishing pigs?
Isospora suis
Clostridium perfringens type C
E. coli
Rotavirus
Salmonella

A

Answer: Salmonella.

The correct answer is Salmonella. Salmonellosis occurs most commonly in grower and finisher pigs. Adults and nursing or weaning pigs are uncommonly affected by Salmonellosis. E. coli, Clostridium perfringens type C, Isospora suis, and rotavirus infections all commonly cause diarrhea in young nursing piglets, but uncommonly in growers and finishers.

24
Q

What is the cause of grass tetany in goats?
Magnesium deficiency
Mycotoxins
Copper deficiency
Calcium deficiency
Magnesium toxicity

A

Anewer: Magnesium deficiency.

The correct answer is magnesium deficiency. Magnesium is important for nervous system function and many enzymatic reactions. The skeletal reserves of magnesium are much smaller than the calcium reserve.
Magnesium deficiency leads to grass tetany. Magnesium toxicity is rare. Grass tetany usually occurs in lactating animals in the early spring on pastures that are well-fertilized with nitrogen and potassium, because high levels of these inhibit magnesium absorption from the GI tract. Copper deficiency causes enzootic ataxia. If you chose mycotoxins, you were probably thinking of grass staggers, which is a different disease.

25
Q

A 3-day-old Suffolk male lamb presents in sternal recumbency with increasing abdominal distension and mild colic (see image). The lamb was bright and alert for the first 2 days of life but has since stopped suckling its dam. Clinical examination reveals that the lamb has no anus. What should you recommend?
Surgical correction is frequently succesful
Medical management with antibiotics and analgesics are necessary until the problem resolves
There is no effective treatment and the lamb should be euthanized
This is normal in lambs and will resolve within 1-2 weeks

A

Answer: Surgical correction is frequently succesful

Atresia of the colon, rectum and anus can all occur congenitally. Often, the clinical sign first noted is progressive abdominal distension. In this case, atresia ani was detected on clinical exam but atresia of the colon or rectum may require radiography to diagnose. Surgical establishment of anal patency can be performed for atresia ani whereas a permanent colostomy may be required for atresia of the colon and rectum.
If surgical correction is attempted, the animal should probably be neutered because of the potential genetic basis for this condition. To perform the surgical correction, a slight bulge in the skin may be present where the anus should be located in lambs or ultrasound can be used to detect the fluid filled rectum. After surgical preparation and local anesthetic injection, an incision to remove the skin over the rectum should be made.
Post-surgically, antibiotics and either mineral oil, DSS, or stool softeners should be given as needed. If possible, twice daily insertion of a thermometer to prevent stricture is preferred.

26
Q

A mare in the last trimester of pregnancy shows signs of colic. She has become anorexic and has been frequently attempting to urinate. Speculum exam is within normal limits. On rectal palpation, you note the broad ligament pulled tight over the uterus from right to left. What is your diagnosis?

  • Ruptured prepubic tendon
  • Normal parturition
  • Breech malpositioning of the fetus
  • Uterine torsion
A

Answer: Uterine torsion.

The correct answer is uterine torsion. These are the typical clinical signs seen in uterine torsions (colic and frequent urination in a late-term mare) and the key finding is the rectal palpation of the tight broad ligament coursing over the uterus. Speculum exam is not diagnostic in horses because torsions typically do not involve the cervix as they do in cows. Medical treatment may be attempted by placing the mare under short-acting anesthesia and rolling her (plank-in-the-flank), or surgical correction may be necessary.

27
Q

A 3-year-old Standardbred gelding presents with epiphora, blepharospasm, and severe pain of the right eye (see image). There are numerous treatment options. Which medication would be contraindicated for this case?

Serum
Neomycin and polymyxin B and dexamethasone (Neo-Poly-Dex)
EDTA
Tobramycin
Tropicamide
Banamine

A

Answer: Neomycin and polymyxin B and dexamethasone (Neo-Poly-Dex)

The correct answer is Neo-Poly-Dex. This is an illustration of a melting ulcer. Any corneal ulcer, whether it is superficial or deep, can be perpetuated by steroid use such as the dexamethasone in this medication.

Steroids increase protease activity causing the “melting” pathology, whereas, one of the primary goals in managing corneal ulcers is to decrease protease activity by using EDTA and serum.

Aggressive topical antibiotic use is also essential. Tobramycin, gentamicin, and neomycin-polymyxin B-bacitracin, among others are appropriate. Intravenous banamine is the drug of choice for ocular pain and inflammation in horses.

Tropicamide is used for its mydriatic and cycloplegic effect because all animals with corneal ulcers have uveitis.

Atropine is an alternative to tropicamide. It is important to note, even though atropine has a longer duration of action than tropicamide, atropine must be used with extreme caution in horses as it may potentiate colic.

28
Q

Which of these is not indicated as the initial treatment of a suspected Streptococcus equi ssp. equi infection, causing mandibular and retropharyngeal lymph node abscessation in a 2-year-old horse?
Lancing the abscess ventrally
Aspirating the lymph nodes for culture and cytology
Systemic penicilin
Isolating the horse

A

Answer: Systemic Penicilin.

The correct answer is systemic penicillin. Streptococcus equi ssp. equi is the agent causing strangles in horses.
When they have lymph node abscessation, antibiotics are contraindicated because they will prolong the course of the disease but will not eliminate it. Because this disease is spread by direct contact, isolation of the horse is important. To obtain a definitive diagnosis, the lymph nodes could be aspirated. The treatment is to lance abscesses ventrally and dispose of all the material from the abscess to prevent spread of the organism.

29
Q

Calculate the extracellular volume of a 450kg horse.
45L
300L
270L
180L
90L

A

Answer: 90L

The correct answer is 9OL. Total body water is 60% of body weight. Extracellular fluid is approximately 1/3 of total body water, therefore
450kg x .6 = 270L total body water
270L x .33 = 89.1L ECF.
ECF is composed of plasma, interstitial fluid and transcellular lymph such as CSF and synovial fluid.

30
Q

A 9-year old racing Thoroughbred presents with clinical signs of lethargy, symmetric hind-limb ataxia, a hypotonic tail, urine dribbling, and a history of a fever. On physical examination, the horse’s vital parameters are within normal limits but you do observe urine dribbling and ataxia. Upon rectal palpation the urinary bladder is enlarged and when pressure is placed on the bladder, urine is expressed from the urethra. The CBC and biochemistry profile are relatively normal and you decide to collect cerebrospinal fluid (CSF) from the lumbosacral space. Results of CSF analysis yields the following:
Color Xanthochromic
Total Protein 196 mg/dL (reference interval 50-80 mg/dL)
Total Nucleated Cell Count 6 cells/mcL (ref interval less than 5 cells mcL)
Cytology Occasional macrophages and lymphocytes observed
Based on the information provided, what is the most likely diagnosis and diagnostic test?

West Nile Encephalitis (WNV); Serum Immunoglobulin M (IgM) capture ELISA
Verminous encephalitis (Micronema deletrix); Culture of CSF
Equine Protozoal Myelitis (EPM); Western Blot of CSF
Cervical Vertebral Malformation (CVM); myelography of the cervical spine
Equine Herpes Virus (EHV) Myeloencephalitis; Virus isolation of buffy coat, nasal swab, and/or CSF

A

Answer: Equine Herpes Virus (EHV) Myeloencephalitis: Virus isolation of Buffy coat,nasal swab, and/or CSF

The correct answer is Equine Herpes Virus Myeloencephalitis. Clinical signs that are common with EHV myeloencephalitis include bladder paralysis with urine dribbling, fecal retention, and hindlimb ataxia. The xanthochromic CS with the high protein and normal cell count (albuminocytologic dissociation) is also very suggestive of EHV myeloencephalitis. Virus isolation can be attempted on buffy coat samples, nasal swabs,
and/or CSF in an attempt to identify the virus.

31
Q

Which of the following is a characteristic often associated with bovine pyometra?

  • Diarrhea
  • Marked abdominal pain
  • Polyuria/polydipsia
  • High fever
  • Inappetence
  • Few if any overt signs
A

Answer: Few if any overt signs

Unlike the bitch, who shows overt signs, including polydypsia, polyuria, inappetence, and sometimes high fever and diarrhea, the cow shows very few external signs of pyometra.

Cows localize the problem to the uterine lumen.

Diagnosis in cows is obtained by transrectal palpation or transrectal ultrasonography.

32
Q

A beef cattle farmer from California has had recurrent problems with roundworm infestations of Ostertagia ostertagi. The fall rains are approaching and, historically, this has been a time when he has had large numbers of cattle become ill. You randomly select 10 animals to perform a fecal egg count on and do not find elevated egg levels.

What do you suspect is occurring and what will you recommend?

The cattle are suffering from type I ostertagiasis; treat with fenbendazole
The cattle are suffering from type Ill ostertagiasis; treat with fenbendazole
The cattle are suffering from type I ostertagiasis; treat with levamisole
The cattle are suffering from type ll ostertagiasis:; treat with ivermectin
The cattle are unlikely to have an outbreak this year; no treatment is needed

A

Answer: The cattle are suffering from type II ostertagiasis:; treat with ivermectin

Outbreaks in autumn into winter in climates like California with hot dry summers and cool wet fall and winter are associated with type Il ostertagiasis in the cool season. In this manifestation of disease, fecal egg counts are low and there are thousands of inhibited early fourth-stage larvae ready to exit the abomasal glands. Once a full blown type Il infection occurs, many larvae emerge, causing dysfunction of the abomasum and possibly leading to severe albumin loss, diarrhea, and even death.
In contrast, type I ostertagiasis in California climates occurs in winter and spring following rapid infection with large numbers of L3 larvae from heavily contaminated pastures (or on irrigated summer pasture). Egg counts in this scenario tend to be much higher and clinical disease is most common in younger animals after weaning.
However, in older animals, after invading the abomasal mucosa, many of the larvae have inhibited or delayed development at the L4 stage and wait for favorable climate conditions to emerge and cause type Il disease.
In climates with rainy summers and freezing winters the emergence will often be in spring. So climate affects the time that Type Il is seen.
As for treatment, benzimadazoles (i.e. fenbendazole) and ivermectin are generally more effective than levamisole but all are treatment options.

33
Q

Several lambs in a hobby flock are reported to be acting sick and not eating. On examination of the affected lambs, you note low grade fevers and lesions around the gums, and in some cases, the proliferative lesions seen in the photo. Several ewes also have similar lesions on their teats. Your diagnosis is

Bovine papular stomatitis
Contagious ecthyma
Foot and Mouth disease
Pseudocowpox
Bluetongue

A

Answer: Contagious ecthyma

Also known as orf and soremouth, CE is mainly a disease of sheep and goats. It also affects humans, as do the other two parapox viruses, bovine papular stomatitis and pseudocowpox, which are found in cattle. CE is rarely fatal but causes lesions in mouths of lambs/kids and sometimes on the teats of the mothers, making nursing a problem.
The virus remains in the scabs that fall off.

34
Q

Several lambs in a hobby flock are reported to be acting sick and not eating. On examination of the affected lambs, you note low grade fevers and lesions around the gums, and in some cases, the proliferative lesions seen in the photo. Several ewes also have similar lesions on their teats. Your diagnosis is

Bovine papular stomatitis
Contagious ecthyma
Foot and Mouth disease
Pseudocowpox
Bluetongue

A

Answer: Contagious ecthyma

Also known as orf and soremouth, CE is mainly a disease of sheep and goats. It also affects humans, as do the other two parapox viruses, bovine papular stomatitis and pseudocowpox, which are found in cattle. CE is rarely fatal but causes lesions in mouths of lambs/kids and sometimes on the teats of the mothers, making nursing a problem.
The virus remains in the scabs that fall off.

35
Q

What is the most common cause of infectious abortion in sheep in North America?
Leptospira
Bluetongue virus
Campylobacter
Brucella
Coxiella

A

Answer: Campylobacter

Campylobacter infection (or vibriosis) is the most significant cause of abortion in sheep in North America. C. jejuni is the most common and C. fetus is the other main cause of abortion. Other common causes are Toxoplasma and Chlamydia psittaci. Bluetongue is much less common.
Brucella ovis rarely causes abortion in sheep although it does cause epididymitis. Sheep are not very susceptible to abortion from leptospirosis. Q fever, or Coxiella burnetii, is an uncommon cause of abortion and is more of concern due to zoonotic
potential.

36
Q

What is the most common bacterial cause of infectious pneumonia in sheep and goats?
Pasteurella pneumoniae
Histophilus somni
Mannheimia hemolytica
Mycoplasma bovis

A

Answer: Mannheimia hemolytica

The correct answer is Mannheimia hemolytica, formerly called Pasteurella hemolytica.
Mannheimia pneumonia is the most common infectious bacterial disease of sheep and goats.
Most cases are caused by M. hemolytica type A. A variety of predisposing factors are suspected.
Clinical signs include fever, depression, mucopurulent nasal discharge, coughing, pulmonary crackles and wheezes, and tachypnea.
Necropsy lesions are fibrinopurulent pleuropneumonia.
Pasteurella multocida is also a cause of pneumonia in sheep and goats. P pneumoniae is a made up name.

37
Q

Which of these is not a clinical sign of bluetongue in sheep?
Lameness
Seizures
Profuse nasal discharge
Edema of the muzzle and face
Teratogenesis

A

Answer: Seizures

The answer is seizures. Clinical signs of bluetongue result from generalized vasculitis and generally include fever, edema, nasal discharge, crusting around the nose, hyperemic mucous membranes, oral ulcers, pulmonary edema, lameness (from coronitis and myositis), diarrhea, leukopenia, and teratogenesis. Cyanosis of the tongue is how the disease got its name.

38
Q

When working to control porcine reproductive and respiratory syndrome (PRRS) virus in a herd, what is the proper order for the different steps needed to achieve this goal?
Homogenize -> Close - Diagnose
Diagnose - Close -> Homogenize
Homogenize - Diagnose -> Close
Diagnose -> Homogenize -> Close
Close - Diagnose -> Homogenize
Close -> Homogenize -> Diagnose

A

Answer: Diagnose - Close -> Homogenize

The correct answer is Diagnose -> Close →>
Homogenize. The first part in any control program is to have the correct diagnosis. Once the correct diagnosis is confirmed then the next step is to close the herd to new introductions. By closing the herd we minimize the introduction of new susceptible animals which can then be exposed to the virus. This is like adding new wood to a fire. The final stage is to homogenize the herd. Here the goal is to get all animals on the farm to be exposed to the virus at the same time. The PRRS virus does not appear to move very quickly within a herd (low contagiousness). By having a homogenous population we prevent having susceptible animals left in the population and thus the virus is likely to die out on its own (no new hosts available).

39
Q

When working to control porcine reproductive and respiratory syndrome (PRRS) virus in a herd, what is the proper order for the different steps needed to achieve this goal?
Homogenize -> Close - Diagnose
Diagnose - Close -> Homogenize
Homogenize - Diagnose -> Close
Diagnose -> Homogenize -> Close
Close - Diagnose -> Homogenize
Close -> Homogenize -> Diagnose

A

Answer: Diagnose - Close -> Homogenize

The correct answer is Diagnose -> Close →>
Homogenize. The first part in any control program is to have the correct diagnosis. Once the correct diagnosis is confirmed then the next step is to close the herd to new introductions. By closing the herd we minimize the introduction of new susceptible animals which can then be exposed to the virus. This is like adding new wood to a fire. The final stage is to homogenize the herd. Here the goal is to get all animals on the farm to be exposed to the virus at the same time. The PRRS virus does not appear to move very quickly within a herd (low contagiousness). By having a homogenous population we prevent having susceptible animals left in the population and thus the virus is likely to die out on its own (no new hosts available).

40
Q

You are called out to a dairy herd that has recently been experiencing reproductive problems. The cows were all acquired 1 year ago from an unknown source and have no known vaccinations or tattoos. The dairyman reports that several cows have had late abortions (6-7 months gestation) and weak or stillborn calves in the past year and he’s never had this problem before. Several of the cows that had abortions developed placental retention and/or metritis. None of the younger pre-pubescent heifers are displaying any clinical signs. You perform a necropsy on two recently aborted fetuses and find lung consolidation in one but no other obvious abnormalities.
Which of the following should you recommend?
Serologic testing for Neospora
Test for Trichomoniasis
Test for Campylobacter fetus subsp venerealis

Serologic testing for Brucellosis

Serologic testing for Brucellosis

A

Answer: Serologic testing for Brucellosis

You should be most suspicious of Brucellosis based on the assortment of signs (abortions, retained placenta, metritis and lack of signs in younger animals), the timing of abortions (last half of pregnancy), and the relatively normal appearance of the examined fetuses. Plus the cattle are not tattooed as they should be if they were given calfhood brucella vaccine. Tritrichomonas fetus abortions usually occur in the first half of gestation but do have placentitis and pneumonia in the fetus as does Brucella. Campylobacter fetus subsp venerealis usually causes early embryonic death.
Neospora abortions are usually mid gestation and cause necrosis of the cotyledons, with fetal lesions including myocarditis, hepatitis, myositis and encephalitis.

41
Q

A dog presents with acute onset vomiting, hemorrhagic diarrhea and fever. On fecal examination, you find many large fluke eggs. You question the owner and discover that the dog was recently in Oregon on a boating trip. What agent is most likely causing the clinical signs in this dog?

A. Rickettsia rickettsii
B. Nanophyetus salmincola
C. Oxytrema silicula
D. Neorickettsia helminthoeca

A

Answer: Neorickettsia helminthoeca

The correct answer is Neorickettsia helminthoeca.

This rickettsial organism is the causative agent of salmon poisoning. It is carried in the fluke, Nanophyetus salmincola, which requires the snail, Oxytrema silicula in its life cycle. The snail is what confines occurrence of salmon poisoning to the northwest coast.

42
Q

What tumor type is a cat predisposed to developing at vaccination sites?
A. Fibrosarcoma
B. Lymphoma
C. Melanoma
D. Squamous cell carcinoma

A

Answer: Fibrosarcoma

The correct answer is fibrosarcoma. Vaccine-associated fibrosarcomas are very well documented in cats.

43
Q

A 4-year old male Thoroughbred horse presents to you for colic. During your work up, you note a painful enlargement at the root of the mesentery on rectal palpation. You suspect that the cause of the horse’s colic are adults from the egg shown in the picture below. Which of the following drugs effectively kills the adult organisms that can cause this condition?
A. Piperonyl butoxide
B. Metronidazole
C. Rifampin
D. Praziquantel
E. Ivermectin

A

Answer: Ivermectin

Colic with an associated painful mass at the root of the mesenery is suspicious for verminous arteritis caused by damage to the cranial mesenteric artery and its branches by Strongylus vulgaris. The strongyle egg shown in the picture confirms the cause in this question. A number of anthelmintics are effective including benzimidazoles, pyrantel and ivermectin.
Praziquantel is effective against tapeworms. Rifampin and metronidazole are antibacterial drugs. Piperonyl butoxide is a pesticide synergist used in insecticide mixtures in horses.

44
Q

A man presents his middle aged female spayed indoor/outdoor cat for having difficulty breathing. Her gums are pink but she has moderate tachypnea and temperature is 104.1 F (40.1 C). The lung sounds are quiet. You perform a thoracocentesis and retrieve a pleural effusion that is white with a yellow tinge. It has a foul odor when you empty the syringe. What treatment do you advise?

  • Drain the effusion via thoracocentesis and start furosemide for congestive heart failure
  • Culture the fluid and start antibiotics, the fluid will resorb after the infection is treated
  • Drain the fluid via thoracocentesis, start a low fat diet and benzopyrone (Rutin)
  • Place a chest tube to drain and lavage chest and administer IV antibiotics
  • Euthanasia due to the cat likely having FIP and the prognosis is grave
A

Answer: Place a chest tube to drain and lavage chest and administer IV antibiotics

Explanation
This cat has pyothorax which is an accumulation of pus within the pleural cavity. In cats, the most common cause is a bite wound that introduces bacteria into the chest cavity. It can also be seen with migrating foreign body, or extension of pneumonia into the pleural space. At minimum, hospitalization with chest tube, drainage and lavage of the pleural space, and antibiotics are needed. Sometimes surgical exploration is required

While this cat could have FIP, the foul odor and presence of bacteria indicate a suppurative infection which is not typical for FIP.

Congestive heart failure can present as pleural effusion in cats, but fever and this type of effusion are not typical of heart failure.

Culturing the fluid is important. However, the fluid will not resorb and the fluid must be removed and the pleural space lavaged.

A low fat diet and Rutin are treatments for pleural effusion caused by chylothorax which is an accumulation of lymphatic fluid within the pleural space.

45
Q

A nine-year-old Quarterhorse mare is presented with a right hind limb lameness. She tends to drag the right toe, and has a stabbing gait in that limb (adducts hindlimb, then suddenly abducts it just before the hoof hits the ground). Hock flexion of the right hind significantly exacerbates the lameness for 5-6 strides. A radiograph of the hock is taken, shown below. What is the common name for this problem?

  • Osselets
  • Bone spavin
  • Tarsal hydrathrosis
  • Splints
  • Ringbone
A

Answer: Bone spavin.

This is bone spavin, an osteoarthritis/degenerative joint disease of the distal hock joints, usually affecting the distal intertarsal and tarsometatarsal articulations. The number one hock problem (tarsus) in horses.

If the horse is lame due to bone spavin, it tends to drag toe or have “stabbing” gait in the affected hindlimb. Occasionally you may see thickening of the soft tissues over distal hock joints. The problem can be unilateral or bilateral with various degrees of lameness.

Typical Tx: intra-articular steroids and hyaluronic acid, phenylbutazone as needed, continue with work. Over time distal hock joints are likely to ankylose (fuse) on their own and lameness ends. Additional treatments include shockwave, bisphosphonates, alcohol arthrodesis, cunean tenectomy or neurectomy.

Tarsal hydrarthrosis (bog spavin) is a chronic synovitis of the tarsocrural joint - look for swelling and distention of the joint capsule.

Link: Synovitis / Capsulitis of the Tarsocrural Joint in Horses
https://www.merckvetmanual.com/musculoskeletal-system/lameness-in-horses/synovitis-capsulitis-of-the-tarsocrural-joint-in-horses

46
Q

You are asked to perform a necropsy on a 17-year old Standardbred mare on a large horse ranch. Although not related to the cause of death, you notice the parasite shown in the image within the stomach. You tell the owner that this parasite is also responsible for the eggs that he sees seasonally on the hair of the front legs of his horses. The owner asks what should be done about this. You discuss the importance of promptly cleaning up feces and transporting feces away. In addition, which of the following is the most appropriate recommendation for ongoing control of this parasite?

  • Administer Ivermectin twice annually, once in the early summer and again in the fall
  • Administer Ivermectin twice annually, once in the early spring and again in the winter
  • Administer Fenbendazole twice annually, once in the early summer and again in late summer
  • Administer fenbendazole twice annually, once in the early spring and again in the fall
  • There is no need to treat these parasites because they are not associated with disease in horses
A

Answer: Administer Ivermectin twice annually, once in the early summer and again in the fall

This case describes the appearance of the horse bot fly, Gasterophilus spp. Gasterophilus is frequently asymptomatic but treatment is recommended because bots can cause gastritis and frequently are a source of annoyance and stress to horses. In addition, the larval instars can cause stomatitis, and colic.

The key to answering this question regarding optimal treatment and management is an understanding of the Gasterophilus life cycle. Gasterophilus undergoes complete metamorphosis, including three larval instars and only one generation is produced per year. The general cycle typically begins with the female ovipositing 150-1,000 eggs on a horse during the early summer months directly on single hairs of the horse’s front legs (especially around the cannon bone area) as well as the abdomen, flanks, and shoulders. The eggs are approximately 1-2mm long and are pale to grayish yellow attached near the tip of the hair.

The eggs develop into first instar larvae within five days and they are stimulated to emerge by the horse licking or biting at the fully developed eggs. The larvae then crawl to the mouth or are ingested and subsequently bury themselves in the tongue or gingiva and remain for approximately 28 days. The larvae molt to the second stage and move into the stomach. The second and later third stage larvae typically attach to the lining of the stomach in the non-glandular portion near the junction of the esophageal and cardiac regions where they remain immobile for the following 9 to 12 months.

The third instar larvae are relatively large, between 1-2cm long with a rounded body, narrow, hooked mouthparts, and spines. The hooked mouthparts enable the larvae to securely attach to the lining of the stomach and intestinal tract. After the third instar larvae have matured, they detach from the gastrointestinal tract and pass from the horse’s body in the feces. The larvae burrow into the soil or dried manure where they pupate and remain for the next one to two months. This stage of the life cycle occurs between late winter and early spring.

Based on this life cycle, the recommended management protocol is typically to treat with an avermectin to control adults and all larval stages by administering in the early summer, shortly after any eggs are seen and again in the fall at the end of the botfly season. Such a control program will substantially reduce fly numbers.

47
Q

Cytological evaluation of a blood smear from a sick horse reveals the following (see below). Which constellation of signs would you expect in a typical acute case of a horse with this disease?

  • Nystagmus, head tilt, strabismus
  • Limb edema, ventricular arrhythmias, ataxia
  • Fever, petechiations, hemolytic anemia
  • Weight loss, partial anorexia, poor performance
  • Elevated serum liver enzymes, hyperammonemia, head-pressing
A

Answer: Fever, petechiations, hemolytic anemia

This cytology shows Babesia caballi, one of the causative agents of equine piroplasmosis (the other is Theileria equi - looks like a maltese cross under the microscope) and acute disease is characterized by fever, petechiations, and signs consistent with hemolytic anemia.

Piroplasmosis is characterized by hemolytic anemia and is spread primarily by ixodid ticks or blood contamination. It is endemic in tropical, subtropical, and some temperate regions.

It is REPORTABLE in the USA.

Clinical infection can be acute, chronic, or inapparent, depending on strain, the horse’s health, and geographic region.

Acute clinical signs include those described here along with lethargy, anorexia, pale or icteric mucous membranes, and with worsening disease - tachycardia, tachypnea, weakness, and hemoglobinuria. Weight loss, poor performance, and partial anorexia can be seen along with mild anemia in horses with chronic piroplasmosis.

Dx: Demonstrate intra-erythrocytic organisms on blood smear and/or serology.

Rx: Imidocarb dipropionate and supportive care. There is a different duration of Tx depending on whether in endemic or nonendemic region (because trying to treat clinical signs in endemic region vs. clear disease in nonendemic region).

Limb edema, ventricular arrhythmias, and ataxia (the latter two uncommonly) can be seen with Anaplasma phagocytophila infections in horses, along with fever, petechiations, icterus, and depression.

Link: Equine Granulocytic Anaplasmosis
https://www.merckvetmanual.com/generalized-conditions/equine-granulocytic-anaplasmosis/equine-granulocytic-anaplasmosis?redirectid=31747

Key Information on Equine Granulocytic Anaplasmosis

Etiology and Transmission

•	Causative Agent: Anaplasma phagocytophilum.
•	Vector: Ixodes ticks (e.g., I. pacificus, I. scapularis).
•	Transmission: Tick bites; seasonal occurrence.

Clinical Signs

•	Fever: Up to 107°–108°F.
•	Symptoms: Depression, limb edema, ataxia, anorexia, icterus, petechiation.
•	Blood Abnormalities: Leukocytopenia, pancytopenia, thrombocytopenia, cytoplasmic inclusion bodies in neutrophils.

Diagnosis

•	Tests: PCR, serology, blood smear (Giemsa or Wright-Leishman stain).
•	Differential Diagnoses: Viral encephalitis, equine infectious anemia, liver disease.

Treatment and Control

•	Antibiotics: Oxytetracycline.
•	Supportive Care: Corticosteroids, fluid therapy, pain management.
•	Prevention: Tick control; no vaccine available.
48
Q

A two-day-old calf has a GGT level of 500 times the adult upper reference range. Which one of the following choices is the most likely interpretation?

  • Due to colostrum absorption
  • Suggestive of a congenital liver shunt
  • Associated with neonatal cholestasis
  • Caused bu traumatic placental detachment
  • Related to bone development
A

Answer: Due to colostrum absorption.

Very high GGT levels are seen with colostrum absorption.

In newborn calves, lambs, and pups, an increase in GGT up to a 1000 times is normal when they receive high levels of colostrum from the dam. In calves it takes four to six weeks for these GGT levels to return to the normal adult reference range.

High levels of GGT are produced in the mammary epithelium during lactation. When evaluating bloodwork, make sure to utilize reference ranges specific for the age of the patient.

Link: Enzyme Activity in Hepatic Disease in Small Animals
https://www.merckvetmanual.com/digestive-system/laboratory-analyses-and-imaging-in-hepatic-disease-in-small-animals/enzyme-activity-in-hepatic-disease-in-small-animals?redirectid=5286?ruleredirectid=30#v3267944

Link: Diagnosis of Hepatic Disease in Large Animals
https://www.merckvetmanual.com/digestive-system/hepatic-disease-in-large-animals/overview-of-hepatic-disease-in-large-animals#v3265330

Enzyme Activity in Hepatic Disease in Small Animals

Key Enzymes

1.	Aminotransferases (ALT, AST):
•	ALT (Alanine Aminotransferase):
•	High concentrations in the liver.
•	Increased levels indicate hepatocellular necrosis.
•	Sensitive for liver injury but not specific.
•	AST (Aspartate Aminotransferase):
•	Present in liver, muscle, and other tissues.
•	Increased levels can indicate liver or muscle damage.
2.	Alkaline Phosphatase (ALP):
•	Elevated in cholestatic disorders and bone growth.
•	Low specificity in dogs due to multiple isoenzymes (L-ALP, G-ALP).
3.	Gamma-Glutamyl Transferase (GGT):
•	Primarily from the liver.
•	Elevated in biliary disease and some neoplasms.
•	High specificity but lower sensitivity compared to ALP.

Diagnostic Considerations

•	Magnitude and Pattern of Enzyme Changes:
•	Mild, moderate, marked increases.
•	Hepatocellular vs. cholestatic patterns.
•	Sequential Measurements:
•	Rate of change helps predict disease activity.
•	Persistent vs. cyclic changes.

Conditions and Findings

•	Acute Hepatic Necrosis:
•	Sharp increase in ALT and AST.
•	ALP increase occurs later.
•	Chronic Hepatitis:
•	Cyclic elevations in ALT.
•	ALP may increase due to ductal response.
•	Toxin-Induced Hepatopathy:
•	Specific toxins can blunt enzyme activity.
•	Examples include aflatoxicosis, microcystin.

Treatment Implications

•	Glucocorticoids and Anticonvulsants:
•	Can induce ALP and GGT.
•	Monitor enzyme levels during therapy.
•	Colostrum Ingestion in Neonates:
•	Transient increase in ALP and GGT.

Clinical Utility

•	Interpretation:
•	Use enzyme levels alongside clinical signs and other diagnostic tests.
•	Differentiates between hepatic and extrahepatic causes.
•	Specificity and Sensitivity:
•	ALT: Highly sensitive for liver injury.
•	ALP: Sensitive but not specific.
•	GGT: Specific but less sensitive.
49
Q

A female veterinarian is pregnant and her physician tests her serologically for toxoplasmosis. IgM is negative. IgG is positive. What is the most appropriate interpretation?

  • Mother is safe, baby at risk
  • Both mother and baby at risk
  • Mother at risk, baby is safe
  • Need to re-check in 2 weeks for rising titers
  • Both mother and baby are safe
A

Answer: Both mother and baby are safe.

The toxoplasmosis organism causes birth defects in a developing fetus if a mother is infected for the first time in her life while pregnant (ie: IgM positive while pregnant).

Toxoplasmosis is not generally dangerous to immune-competent people and a positive IgG result suggests a previous infection.

There are challenges to toxoplasmosis testing in pregnant women (false positives).

If a pregnant woman is IgM positive, confirmatory tests must be done.

Click here for more on pregnancy and toxoplasmosis.
https://www.cdc.gov/parasites/toxoplasmosis/gen_info/pregnant.html

Link: Toxoplasmosis in Animals
https://www.merckvetmanual.com/generalized-conditions/toxoplasmosis/toxoplasmosis-in-animals?autoredirectid=14229

Link: Toxoplasmosis Diagnosis
https://www.cdc.gov/parasites/toxoplasmosis/diagnosis.html

Link: Toxoplasmosis
https://www.cdc.gov/dpdx/toxoplasmosis/index.html

Toxoplasmosis in Animals

Definitions and Terminology

•	Toxoplasmosis: A zoonotic parasitic disease caused by the protozoan Toxoplasma gondii.
•	Intermediate Host: Animals (including humans) that harbor the asexual stages of the parasite.
•	Definitive Host: Cats, which harbor the sexual stages of the parasite in their intestines and shed oocysts in their feces.

Causative Agent

•	Toxoplasma gondii: An obligate intracellular protozoan parasite with a complex life cycle involving both sexual and asexual stages.

Life Cycle

1.	Definitive Host (Cat):
•	Ingests tissue cysts from infected prey or raw meat.
•	Parasite undergoes sexual reproduction in the intestines, producing oocysts shed in feces.
•	Oocysts become infective in the environment within 1-5 days.
2.	Intermediate Host (Various Animals and Humans):
•	Ingests infective oocysts from contaminated food, water, or soil.
•	Parasite invades host cells, forming tissue cysts primarily in muscles and the central nervous system.
•	Tissue cysts remain dormant but can reactivate if the host’s immune system is compromised.

Pathophysiology

•	Acute Infection:
•	Tachyzoites rapidly multiply and spread throughout the body, causing cell lysis and tissue necrosis.
•	Immune response limits the spread, converting tachyzoites into bradyzoites within tissue cysts.
•	Chronic Infection:
•	Tissue cysts persist for the life of the host, typically without causing disease unless reactivation occurs.
•	Immunosuppression can lead to reactivation and severe disease.

Clinical Changes and Symptoms

•	Cats (Definitive Host):
•	Often asymptomatic.
•	Kittens and immunocompromised cats may show fever, lethargy, anorexia, pneumonia, hepatitis, and neurologic signs.
•	Dogs and Other Intermediate Hosts:
•	General Signs: Fever, lethargy, anorexia, weight loss.
•	Respiratory: Pneumonia, cough, dyspnea.
•	Neurologic: Ataxia, seizures, paralysis, tremors.
•	Ocular: Uveitis, chorioretinitis.
•	Musculoskeletal: Myositis, lameness.
•	Gastrointestinal: Vomiting, diarrhea, abdominal pain.

Diagnosis

1.	Clinical Examination:
•	History and Physical Exam: Assessing clinical signs and potential exposure risk.
2.	Laboratory Tests:
•	Serology: Detection of antibodies against T. gondii (IgM, IgG).
•	IgM: Indicates recent or acute infection.
•	IgG: Indicates chronic or past exposure.
•	PCR: Detection of T. gondii DNA in blood, CSF, or tissue samples.
•	Histopathology: Identification of tachyzoites or tissue cysts in biopsy samples.
3.	Imaging:
•	Radiography and Ultrasound: To identify organ involvement (e.g., pneumonia, hepatitis).

Management Strategies

1.	Antiprotozoal Therapy:
•	Clindamycin: 10-12 mg/kg orally every 12 hours for 2-4 weeks.
•	Pyrimethamine and Sulfadiazine: Combination therapy to inhibit folic acid synthesis in the parasite.
•	Pyrimethamine: 1 mg/kg orally once daily.
•	Sulfadiazine: 30 mg/kg orally every 12 hours.
•	Trimethoprim-Sulfamethoxazole: Alternative treatment.
•	Dosage: 15 mg/kg orally every 12 hours.
2.	Supportive Care:
•	Fluid Therapy: To maintain hydration and support systemic health.
•	Nutritional Support: Ensuring adequate nutrition during recovery.
•	Anti-inflammatory Drugs: To reduce inflammation and manage pain.
3.	Preventive Measures:
•	Environmental Management: Regular cleaning of litter boxes, preventing hunting, and feeding commercial diets to cats.
•	Hygiene: Proper handling and cooking of meat, washing hands after handling soil or raw meat.

Prognosis

•	Dependent on Severity and Timeliness of Treatment: Early diagnosis and appropriate therapy improve outcomes.
•	Chronic Infections: May require long-term management, especially in immunocompromised animals.

Zoonotic Potential

•	Human Infection: Risk from ingesting undercooked meat, contaminated food or water, or handling cat litter.
•	Pregnant Women and Immunocompromised Individuals: High risk for severe disease, including congenital infection.

Summary for Veterinary Professionals

•	Toxoplasmosis is caused by the protozoan Toxoplasma gondii, affecting a wide range of animals, with cats as the definitive host.
•	Clinical signs vary by species and may include respiratory, neurologic, ocular, musculoskeletal, and gastrointestinal symptoms.
•	Diagnosis involves serology, PCR, and histopathology, with imaging used to assess organ involvement.
•	Management includes antiprotozoal therapy (clindamycin, pyrimethamine-sulfadiazine) and supportive care.
•	Prognosis varies with the severity of the infection and timeliness of treatment.
•	Preventive measures focus on environmental management and hygiene to reduce exposure risk.
50
Q

A herd of pigs is presented for various reasons; some pigs have been found suddenly dead with no other apparent clinical signs. Some animals are febrile, lethargic, unable to rise, and have multifocal diamond-shaped skin lesions over their bodies. Some animals have swollen, painful hocks and carpi. What is the most likely causative agent/diagnosis?

  • Erysipelothrix rhusiopathiae
  • Lawsonia intracellularis
  • E. coli
  • Swine pox
  • Mycoplasma hyosynoviae
A

Answer: Erysipelothrix rhusiopathiae

Explanation
The correct answer is Erysipelothrix rhusiopathiae. There are 3 forms of erysipelas. In the peracute form, pigs are found suddenly dead with no other clinical signs. In the acute form, the pigs become lethargic, painful in their joints, anorexic, and develop diamond-shaped skin lesions. In the chronic form, the arthritis progresses to the vertebral joints and the limb joints may fuse. All three forms of the disease can appear in a herd, particularly if there is noncompliance of vaccination of the herd and if treatment is delayed. The diamond-shaped skin lesions are pathognomonic for the disease.

***PowerLecture: Multisystemic Diseases

51
Q

A 12-year old cat with an unkempt haircoat and palpable thyroid slip presents with a history of weight loss. Appetite has been normal to increased. Bloodwork is unremarkable and total T4 level is 3.8 ug/dL (normal 0.8-4.0). Although the value is within the reference range, you still suspect hyperthyroidism. Which other test could best support the diagnosis?

  • Blood pressure if hypertension is present
  • Serum thyroglobulin antibodies
  • Ultrasound of the thyroid gland
  • Free T4 by equilibrium dialysis
  • Chest radiographs showing a valentine shaped heart, or evidence of HCM
A

Answer: Free T4 by equilibrium dialysis

Explanation
An elevated free T4 by equilibrium dialysis is a way to support the diagnosis of occult hyperthyroidism. In a small subset of cats, the free T4 is elevated due to non-thyroidal illness. Therefore, hyperthyroidism should not be diagnosed on a free T4 measurement alone. Most older cats have a thyroid level that is in the lower end of the normal range. The T4 in this cat is in the high end of the normal range. In combination with the exam findings and clinical signs, this raises suspicion for hyperthyroidism.

Many hyperthyroid cats have hypertension so this is a test that should be checked. However, many older cats also have hypertension that do not have hyperthyroidism so this would not confirm the diagnosis. The same applies with appearance of the heart on radiographs. Many hyperthyroid cats will have thickening of the ventricles and an enlarged heart on radiographs, but this radiographic finding would also be seen in cats with hypertrophic cardiomyopathy (HCM) as well as with other cardiomyopathies.

Ultrasound of the thyroid gland would not be of much benefit. It may show that the gland is enlarged but would not confirm that it is overproductive. Serum thyroglobulin antibodies are used to aid in the diagnosis of hypothyroidism, which is rare in cats.

52
Q

A premature foal presents for examination. Physical examination is unremarkable, but the owner wishes to rule out an angular limb deformity prior to selling the foal. What diagnostic test would provide the most information about whether the foal will develop an angular limb deformity?

  • Full body bone scan
  • Radiographs of the long bones of the limbs
  • Carpal and tarsal radiographs
  • Ultrasound of the flexor tendons
  • Nerve blocks
A

Answer: Carpal and tarsal radiographs

Explanation
The correct answer is carpal and tarsal radiographs. In a young foal that was born prematurely, palpation alone is insufficient to detect angular limb deformities. The carpus and tarsus are the common sites for such deformity to occur, and radiographs will provide the best information about the bony conformation.