Avian

Question 1

Candidiasis

Dx?

Tx?

Answer 1

• Candida albicans is a common environmental fungus that can infect the digestive tracts of birds. It is a common cause of ‘sour crop’ or a crop infection (ingluvitis)
• Young birds are most commonly affected.
• Infection involves the crop mucosa, and secondary bacterial infection is common.
• Affected birds will be unthrifty, underweight, and may vomit.
• Crop stasis and malabsorption syndrome may be associated clinical findings.
• Diagnosis is by culture and identification of the yeast.
• Treatment options are nystatin, itraconazole, fluconazole, and vitamin A supplementation

Question 2

What is the only way Aspergillus can infect?

What is the disease caused by the nodules formed in the lung called?

Answer 2

• Inhalation of the fungal spores is the only route of transmission of Aspergillus.
• When the fungus is inhaled, it may cause nodules to form in the lungs, also known as granulomatous pneumonia.
• Inhalation of fungal spores can cause yellow to tan nodules in the lung

Question 3

Mycobacterium Avium

Answer 3

• Tuberculosis occurs worldwide in birds as a contagious, chronic, bacterial disease caused by members of the Mycobacterium avium complex
• Mycobacterium avium, is somewhat resistant to most of the antibiotic medications that are utilized when humans get tuberculosis, so multiple medications are often required over extended periods of time to eliminate the infection.
• Mycobacterium infections in birds can cause avian tuberculosis, a contagious and often fatal disease that can affect birds of any variety but is most prevalent in chickens and wild birds raised in captivity.

Signs of mycobacterium infection may include:

• Atrophy of sternal muscles
• Depression
• Diarrhea
• Distended abdomen
• Gradual wasting
• Increased urination
• Labored breathing
• Lameness or difficulty perching
• Lethargy
• Loss of appetite
• Poor feather conditions
• Weight loss

Question 4

What disease of pheasants is caused by an adenovirus that is closely related to hemorrhagic enteritis virus of turkeys?

Answer 4

• marble spleen disease
• Both Marble spleen and Hemorrhagic Enteritis are type 2 siadenoviruses.
• Avian influenza is an orthomyxovirus, avian encephalomyelitis is a picornavirus, infectious bursal disease is a birnavirus, and Newcastle is a paramyxovirus

Question 5

• A broiler flock has increased mortality and you conduct a necropsy to find three lesions: fibrinous pericarditis, perihepatitis and airsacculitis.

What infectious agent is usually the cause of this classic triad of lesions?

Answer 5

• Escherichia coli
• Large numbers of E.coli are often found in poultry houses due to fecal contamination.
• Poultry routinely exposed to large numbers of pathogenic E. coli become systemically infected when the bacteria gain access to the bloodstream via the respiratory tract or intestine.
• If the bird survives septicemia, they often develop subacute fibrinopurulent airsacculitis, pericarditis and perihepatitis as well as lymphocytic destruction of the bursa and thymus

Question 6

Which species of bird does iodine deficiency most commonly occur?

Answer 6

• BUDGIES (i.e. Budgerigars)
• Iodine deficiency in budgerigars causes goiter or thyroid hyperplasia.
• Clinical signs are usually respiratory-related due to pressure of the enlarged thyroid on the syrinx.
• Regurgitation may also occur due to blockage of the thoracic inlet.
• Treatment and prevention include iodized calcium blocks or specially-iodized seed mixes

Question 7

Pacheco’s Disease

What is it caused by?

Answer 7

Herpesvirus

• Pacheco’s disease is a highly acute and fatal disease of pet birds.
• Signs are nonspecific but include lethargy, anorexia, ruffled plumage, and irregular, yellowish diarrhea.
• Usually distinct changes in environment such as import, quarantine, or pet shop are part of the history in birds with Pacheco’s disease
• Many species of birds are susceptible.
• Cockatoos and Amazon parrots are very susceptible to the infection and usually die, whereas conures, such as the Nanday and Patagonian Conures seem to be resistant to the disease

Question 8

“Bluecomb”

(Transmissible Enteritis)

Answer 8

• This condition, caused by a coronavirus is known as bluecomb, transmissible enteritis, or coronaviral enteritis. Signs may be similar to Salmonella or hexamitiasis (a protozoan parasite)
• Dx: Direct fluorescent antibody for viral antigens in intestines
• Definitive diagnosis is based on demonstration of coronaviral antigens in the intestines or by electron microscopy to detect coronavirus particles in the intestinal contents. There is also a commercial ELISA that can detect some infections
• The disease is usually treated supportively with supplemental heat, nursing care, and antibiotics to prevent secondary bacterial infections.
• There is no vaccine available so control depends on thorough cleaning and disinfection of buildings and equipment.

Question 9

Avian Malaria

Answer 9

• Avian malaria is a vector-transmitted disease caused by protozoa in the genera Plasmodium and Haemoproteus; these parasites reproduce asexually within bird hosts and both asexually and sexually within their insect vectors, which include mosquitoes (Culicidae), biting midges (Ceratopogonidae), and louse flies (Hippoboscidae)
• The plasmodium trophozoite is a stage of the parasite that is seen as a large vacuole displacing the nucleus on microscopic examination of red blood cells in infected birds

Question 10

Organophosphate Poisoning

Answer 10

• Organophosphates are toxic to many species of birds and mammals including pets, farm animals, and wildlife species.
• Although the targets are insects, non-target animals can ingest the products from open bait containers or indirectly become exposed by consuming poisoned insects or plant material
• deformities are associated with organophosphate insecticides, particularly parathion, which can cause several vertebral and long bone abnormalities as well as generalized stunting of embryonic development.

Question 11

Chlamydiosis

Answer 11

• Chlamydiosis is caused by Chlamydophila psittaci.
• It is a reportable and zoonotic disease.
• Clinical signs include weight loss, anorexia, lime-green urates, and respiratory signs due to air sacculitis.
• White blood cell counts are often very high with this disease (often 2-10 times normal).
• Lesions include hepatomegaly, splenomegaly, air sac changes and fibrinous pericarditis.
• Transmission occurs by inhalation of nasal exudates or fecal dust.
• Treatment is with tetracyclines

Question 12

Histomonas meleagridis

(chickens v. turkeys)

Answer 12

• This protozoan parasite, also called blackhead or infectious enterohepatitis, is fatal to turkeys but less pathogenic to chickens.
• It causes extensive necrosis of the liver and cecum.
• For this reason, chickens and turkeys should not be housed together and turkeys should not be housed in areas where chickens were previously housed

Question 13

You are working as a relief veterinarian at an exotic animal practice, and a toucan is brought in for evaluation due to a history of poor feathering and an overgrown beak.

Blood work shows elevated liver enzymes and bile acids. What disease common for this species must you rule out?

Answer 13

• hemochromatosis
• Hemochromatosis or iron storage disease is one of the most common causes of toucan mortality in captivity.
• The liver may show areas of necrosis and degenerative processes.
• Etiological factors are the excessive dietary iron and high rates of iron absorption and retention in susceptible bird species
• Given the clinical signs, blood work results, and species, it is very important to consider hemochromatosis, as both toucans and mynah birds seem susceptible

Question 15

Sternostoma tracheacolum

Answer 15

• air sac mite.
• It is contagious and often causes dyspnea and respiratory distress in certain finch species.
• It can sometimes be visualized within the trachea of these tiny birds by wetting the feathers of the neck and placing a small, bright light source across the trachea.
• Sternostoma tracheacolum was found to be ovoviviparous, laying eggs in the lung of the host. Larvae hatch shortly after oviposition and moult without feeding.
• Gravid females tend to occupy the airsacs, the syrinx and trachea of the host while adult non-gravid, non-gorged females are more commonly found in the upper respiratory system, particularly the buccal and nasal cavities

Question 16

Haemoproteus

Answer 16

• Haemoproteus spp is the most common blood parasite in birds, especially nondomestic birds.
• Birds are usually asymptomatic; however, Haemoproteus infection may be more often significant than previously thought - Anemia, anorexia, weight loss, and depression have been reported.
• Rarely fatal disease occurs. Clinical disease is usually attributed to anemia, presence of megaloschizonts in the musculature, or host-cell destruction.
• Diagnosis of Haemoproteus infection is made by microscopic examination of a peripheral blood smear. Haemoproteus gametocytes partially encircle the nucleus of erythrocytes forming a “halter-shaped” appearance.
• Haemoproteus gametocytes often occupy over one-half of the erythrocyte cytoplasm with little displacement of the host cell nucleus as seen here
• The haemoproteus life cycle involves a blood sucking insect for transmission (mosquitos, lice, and culicoides).
• The infection often does not cause clinical signs but may cause an enlarged gizzard, spleen, liver, or kidney.
• Treatment of choice is the antimalarial drug, chloroquine.

Question 17

The fused lumbosacral region in birds is known as the ___________

Answer 17

Synsacrum

Question 18

3 strains/groups of Newcastle Disease

Answer 18

Newcastle disease is caused by an RNA virus (paramyxovirus-1).

The disease is categorized into 3 groups:

1) Velogenic straina: highly virulent and easily transmitted
2) Mesogenic straina: moderately virulent
3) Lentogenic straina: low virulence

Clinical signs include diarrhea, swelling of the head and neck, gasping, coughing, sneezing, drooping wings, dragging legs, circling, torticollis, paralysis, and clonic spasms.

Diagnosis is based on rapidly spreading respiratory and neurologic disease, in addition to isolation of the organism.

Prevention is via vaccination.

Newcastle disease has the potential of causing a transitory conjunctivitis in humans with very high levels of exposure to the virus.

Question 19

A well-known bird breeder calls to let you know she is bringing in a parrot on emergency with a “tear in the rhamphotheca and a lacerated choana”.

What anatomic structures should you be prepared to examine?

Answer 19

• The beak and the open slit located on the roof of the oral cavity
• The boney beak, bill or rostrum of a bird is covered with a thin horny sheath of keratin that is technically known as the rhamphotheca.
• The choana is the passageway for air from the nasal respiratory system into the oral cavity and is a single slit-like structure on the roof of the mouth in birds

Question 20

When placing an intraosseous catheter in a bird, which bones would be the most appropriate to use?

Answer 20

ULNA or TIBIOTARSUS

• Intraosseous catheters can be placed in birds in either the ulna or the tibiotarsus.
• Birds have pneumatized bones, and these must be avoided with IO catheters, since administration of fluids into a pneumatic bone would drown the bird.

Question 21

Treatment for Chronic Egg Laying

Answer 21

Leuprolide acetate (Lupron)

• Leuprolide acetate is a gonadotropin releasing hormone (GNRH) analog and will shut down the production of reproductive hormones in birds, thus, will often stop ovulation in the laying hen.
• Female birds are capable of producing eggs (infertile) without the presence of a male, just as chickens do.

Question 22

A primarily seed diet in birds can lead to?

Answer 22

• Calcium deficiency
• Birds on all seed diets often have problems with calcium and phosphorus metabolism. Inadequacies in these minerals result in osteoporosis, acute hypocalcemia (weakness, tremors, seizures), rickets and splayleg in young birds, and egg binding
• With seeds as a primary diet, many reproductively active females do not maintain adequate calcium levels to be able to lay eggs normally.
• This leads to weakened contractions of the reproductive tract and an inability to pass eggs through the oviduct.
• Initial therapy should consist of fluid support and calcium prior to attempt to reduce the prolapse
• can see Vitamin A deficiency with seed diets as well –> would see squamous metaplasia affecting the oral mucosa, respiratory and renal systems

Question 23

proventricular dilatation syndrome

Answer 23

• Proventricular dilatation disease is a condition affecting the nerves supplying the gastrointestinal tract of birds, mainly the proventriculus or true stomach.
• Nerves supplying other organs may also be affected, and in some cases, encephalitis (inflammation of the brain) may occur.

Question 24

Allopurinol

Answer 24

• In birds, allopurinol decreases plasma uric acid (PUA) levels
• may be effective in the treatment of gout
• may see spindle shaped crystals in synovial joints or on viscera

Question 25

Which antimicrobial is toxic to birds?

Answer 25

**Gentimycin** **note:** _Oxytetracycline_ is poorly absorbed orally and is given intramuscularly although it can cause irritation/necrosis at injection sites

Question 26

Cnemidocoptes pilae

Answer 26

* **Cnemidocoptes pilae**, is also known as "scaly face" or "scaly leg." * This mite can be treated with topical or oral ivermectin. * It is more common in birds that are immunocompromised, and beak deformity may be permanent even after the mite is cleared.

Question 27

**Psittacine beak and feather disease (PBFD)**

Answer 27

* **Psittacine beak and feather disease (PBFD)** is a viral disease affecting all Old World and New World parrots. * The causative virus–beak and feather disease virus (BFDV)—belongs to the taxonomic genus Circovirus, family Circoviridae * show abnormally coloured and stunted feathers * **Powder loss in cockatoos (**there is usually a loss of powder down, with resulting shiny black beak in those birds whose beaks are usually dusty grey) is a common finding with this disease that you should be aware of. The beak and nails will also be affected. On physical exam, you can also expect feather dystrophy

Question 28

Anthracosis

Answer 28

* **Anthracosis** is a lung disease associated with inhalation of coal dust and carbon particles * there is no need to treat this! just a random finding * appearance of black spots on the air sacs and lungs in a bird are known as anthracosis. * This is considered a routine non-pathologic finding provided there are no other signs of inflammation in those areas and no treatment or management change is needed in birds.

Question 29

**Candida (Candida albicans), hypovitaminosis A, and trichomoniasis (Trichomonas gallinae)** result in what lesion in the mouth of a bird?

Answer 29

**_raised plaques_**. * Hypovitaminosis A causes **squamous metaplasia**. * Candidiasis causes **thickening of crop mucosa.** * Trichomoniasis causes **white caseous lesions in the oral mucosa**.

Question 30

Glipizide

Answer 30

* Diabetes Mellitus type 2 medication * glipizide, has proved to be a more effective treatment for diabetes in birds than injectable insulin, in many cases

Question 31

Preen Gland Birds

Answer 31

* **The uropygial gland**, informally known as the **preen gland or the oil gland**, is a bilobed sebaceous gland possessed by the majority of birds. * It is located dorsally at the base of the tail (between the fourth caudal vertebra and the pygostyle) and is greatly variable in both shape and size * In many species of birds, when present, it provides a **source of oil and nutrients for the bird's feathers.** * Interestingly, not all birds have a uropygial gland. Those without a preen gland include Amazon parrots and several macaw species such as Blue Hyacinth

Question 32

Pecten in Birds

Answer 32

* the "pecten" is present in all birds. * It is a highly vascularized intraocular organ and is believed to nourish the retina and control the pH of the vitreous body * The pecten or pecten oculi is a **comb-like structure of blood vessels belonging to the choroid in the eye of a bird**. * It is a non-sensory, pigmented structure that projects into the vitreous humor from the point where the optic nerve enters the eyeball. * It is present in **all birds and some reptiles.**

Question 33

An adult rabbit presents to you for chronic mucopurulent nasal discharge and sneezing. Which of these agents is likely responsible for the rabbit's clinical signs?

Answer 33

**​Pasteurella Multocida** * **"snuffles"** * This is a common cause of infectious disease in rabbits * The upper respiratory syndrome is the most common presentation for Pasteurella in rabbits, but it can affect many other systems and can cause enzootic pneumonia, otitis media/interna, conjunctivitis, meningitis, encephalitis, reproductive tract infections, abscesses, and septicemia

Question 34

Cutaneous xanthomatosis

Answer 34

* **cutaneous xanthomatosis** is a unique condition of birds caused by excessive accumulation of lipids in the skin. * It is a macrophagic inflammatory response, with **multinucleated giant cells and cholesterol crystals observed cytologically**. * A xanthoma is a benign growth and is most prevalent in cockatiels, budgies and cockatoos. * They are typically non-aggressive, but at times can become locally invasive causing irritation and self-mutilation of the site. * The etiology is unknown but a high fat diet and inactivity may contribute

Question 35

What is the appropriate medication for the treatment of **Psittacosis (Chlamydophila psittaci)**?

Answer 35

**Doxycycline** * The only approved treatments for Chlamydophila are **tetracyclines** such as **_doxycycline and oxytetracycline._** * Generally the duration of treatment must be **AT LEAST 45 DAYS** * Chlamydophila is a reportable disease in most locations

Question 36

Unique Adaptations of Avian Species | (3)

Answer 36

* **Pneumatized bones** * **​**femur and humerus * **Countercurrent air flow** * **​**at level of the lungs * **No diaphragm**

Question 37

"Chrysanthemum disease"

Answer 37

* They are colloquially referred to as **"feather dusters."** * This is an autosomal recessive disorder that results in **continuous growth of feathers all over the body**. * Initially, these birds stand out in the nest as the largest and best feathered of the group. * But over the first days or weeks, the classic appearance becomes obvious. * This frequently results in obscured eyesight, inability to fly, and difficulty preening (use of beak to arrange feather position). * Conventionally, it has been stated that birds with this condition **only live 3-6 months** but with care taken to provide adequate nutrition and supportive care, they can live several years.