Passeriformes

Question 1

Which of the following is true about the passerine foot?

A. Incumbent hallux

B. Zygodactyle unwebed foot

C. Unique arrangement of dorsal tendons

D. Hallux cannot move independent of other digits

E. Presence of tensor propatageous brevis muscle (attaches foot to hip)

Answer 1

A. Same level as other digits

Question 2

Which of the following superfamiles does not require vitamin C (L-gulonolactone oxidase present)?

A. Corvoidae

B. Meliphagoidea

C. Muscicapoidea

D. Passeroidae

E. Sylvioidae

Answer 2

Answer = B, All others lack L-gulonolactone oxidase

A. Corvoidae (crows, birds of paradise)

B. Meliphagoidea (wrens and honey eaters)

C. Muscicapoidea (flycatchers, starlings, thrashers)

D. Passeroidae (weavers, sparrows, finches, tanagers)

E. Sylvioidae (larks, swallows, martins, tits)

Question 3

Which of the following is least sensitive to iron storage disease?

A. Crows

B. Tanagers

C. Birds of paradise

D. Manikins

E. Starlings

Answer 3

A. Crows.

Remember: mynahs are also very susceptible to iron storage disease.

Question 4

Name an anatomical difference between the nasal sinuses of passerines compared to psittacines.

Answer 4

Right and left nasal sinuses have no communication with one another

Question 5

What does these birds have in common: tanagers, birds of paradise, starlings, mynahs, manakins

Answer 5

Sensitivity to excess dietary iron

Question 6

How many air sacs do passerines have and what are they?

Answer 6

Cranial thoracic and clavicular are fused, and then have cervical (2), caudal thoracic (2), and abdominal (2); Passerines have 7 total. Psittacines have 9 total.

Question 7

Do Passeriformes have a crop? A cecum?

Answer 7

Crop yes, cecum vestigial or absent

Question 8

What is the predominant mosquito vector for West Nile Virus?

Answer 8

Culex spp Culiseta melanura is an orniphilic (aka bird loving) species, may amplify virus in birds Aedes vexans may transmit to mammals

Question 9

What is the etiologic agent of black spot disease?

Answer 9

Canary circovirus - Nestlings, coelomic enlargement and congestion of the gallbladder. Seen though the skin and be a “black spot”. Common cause of mortality in canaries.

Produces hepatic necrosis, splenic inclusions, and inclusions in the bursa of fabriscious.

Most commonly affects canaries - also reported in zebra and Gouldian finches.

Question 10

Passerines as a group are asymptomatic carriers of which group of viruses?

Answer 10

Arboviruses; togaviruses WNV, SLE; EEE, WEE, VEE

Question 11

What disease can look similar to Salmonella in passerines and must be differentiated using culture?

Answer 11

Yersinia pseudotuberculosis. Remember both present with enteric type/non-specific signs: Fluffed, weak, lethargy, anorexia, diarrhea, pasty vent, emaciation, trouble swallowing, diarrhea

Question 12

Blood smear and fecal from a tanager. What is your top differential?

Answer 12

Systemic isosporosis (formerly known as Atoxoplasmosis)

Question 13

Describe the lifecycle of atoxoplasmosis?

Answer 13

Which of the following represents the lifecycle of atoxoplasmosis? Ingestion of oocyts > release sporozoites > invade epithelial cells > merogeny (various tissues) > merozoites > sexual reproduction in intestinal epithelium > zygote > oocyst form around zygote > asexual reproduction to become infective

Question 14

Which of the following is TRUE regarding Atoxoplasmosis in passerines?

A. Nestlings are most commonly affected

B. Diagnosis requires identification of sporozoites in monocytes

C. Whole blood smears are preferred for evaluating extraintestinal stages

D. Evaluation of fecal oocyts can differentiate between enteric and systemic isopora

E. Gross pathology consists of enlargement of the liver and spleen and presence of tiny white foci of necrosis through the parenchyma

Answer 14

E. Gross pathology consists of enlargement of the liver and spleen and presence of tiny white foci of necrosis through the parenchyma –> wt loss, diarrhea in adults too. PDzWB CH 5

Question 15

Name the hemoparasite

Answer 15

Leukocytozoan

Typically in leukocytes, but also can be in RBCs Causes marked cell distortion

Question 16

Name the hemoparasite

Answer 16

Hemoproteus

Typically in RBCs, can have some pigmentation Does NOT usually distort the RBC or move the nucleus

Question 17

What is the vector species for Leukocytozoan? For Hemoproteus? For Plasmodium?

Answer 17

L = simulidae (black flies) H = culicoides, hippoboscidae P = culicidae (mosquitoes)

Question 18

Name the hemoparasite

Answer 18

Plasmodium

In RBC, can have some pigmentation

Markedly distorts the RBC and moves the nucleus

Seeing the schizont is confirmatory for this genus

Question 19

Differentials for sinusitis in passerines

Answer 19

Trichomonas gallinae (house finches)

Pox

Mycoplasma gallisepiticum

Hypovitaminosis A

Candida

Question 20

What is the life cycle of avian malaria?

Answer 20

In avian host: Infective sporozoites inoculated with mosquito bite –> localized merogeny in tissue macrophages –> release merozoites –> second stage merogeny throughout body via blood or lymph (liver, brain, etc.) –> metacryptozoites released–> capillary endothelial cells (exoerthrocytic) or RBCs –> in RBC undergo further merogeny to form: More meronts: small, rupture cells and cause pathology or eat cell cytoplasm/hemaglobin (via cytostome) and produce malarial pigment or hematozoin may appear as golden-brown or black granules in the parasite cytoplasm on light microscopy

Gametocytes: infective stage for mosquito vectors; ciruclate unchanged until eaten

The male gametocytes (microgametocytes) typically stain pink with Giemsa stain, while female gametocytes (macrogametocytes) stain pale blue.

In mosquito: Ingested gametocytes –> gametogenesis in mid gut –> merge to form mobile oocyte –> penetrates mosquito gut wall –> sporogeny (a second asexual reproduction stage) –> sporozoites rupture –> penetrate hemoceol and travel to the salivary glands  injected into host

Question 21

What passerine species are amplifying hosts for WNV?

What avian species are sensitive to WNV?

What avian species are resistant to WNV?

Answer 21

Scrub jays, crows, and other corvids House finches House sparrows

Remember species that are sensitive to WNV include loggerhead shrikes, American white pelicans, sage grouse, and corvids.

Resistant species include poultry and rock doves.

Question 22

What passerines are prone to regurgitate with sedation/anesthesia?

Answer 22

Corvids (carnivorous) and mynahs (frugivorous)

Question 23

What is the scientific name of the Raven?

Answer 23

Corvus corax

Question 24

What is the scientific name of the Bali Mynah?

Answer 24

Leucopsar rothschildi

Question 25

What is the scientific name of the Blue-Grey Tanager?

Answer 25

Thraupis episcopus

Question 26

What is unique about the syringeal anatomy of Oscine Passerines?

Answer 26

They have complex muscle morphology that allows for complex vocalization.

Question 27

What makes the passerine genus Pitohui unique?

Answer 27

These birds have batrachotoxins in their skin and feathers.

F8

Question 28

Describe how passerine beak shape is related to diet and give examples of some groups of birds.

Answer 28

Beak shapes and diet (MMWS)

• Young passerines typically eat arthropod inverts
• Crows, thrushes, blackbirds – generalist omnivores – non-specific beak
• Hummingbirds – nectivores – long, slender
• Carnivorous birds – adapted for tearing meat vs. catching fish
• Cardinals – thick, conical – crack large seeds
• Crossbills – crossbite – open pinecones
• Chickadees – short, sturdy – hammer seeds
• Sparrows – small, light – small seeds & plant material
• Doves – soft - use gizzard to grind seed
• Aerial insectivores – broad and flat (martins) vs scoop like (nightjars, night hawks, swifts)
• Arboreal insectivores – slender – get insects from branches
• Woodpecker – drill into tree – eat ants

Question 29

What is the most common reproductive strategy of passerine birds?

What other strategies exist?

Answer 29

Monogamy

Leks - birds or paradise, manakins, cock of the rocks - bright colors elaborate dances

Bower Birds - polygyny - males decorate nests

Parasitic Brooders - cowbirds, whydas

Question 30

Describe the general reproductive pattern of passerine birds.

Answer 30

• Gonads of both males and females may undergo seasonal enlargement and regression.
  
  • May lay from 1 to 12 eggs per clutch, depending on the species.
  • Most eggs patterned or pigmented.
  • Generally 1 egg laid per day.
  • Pip to hatch usually 24h or less.
  • Hatchlings are altricial and nidicolous but may grow rapidly.

Fowler 8

Question 31

Describe proper passerine husbandry in managed care and rehabilitation settings.

Answer 31

• Special Housing Requirements (F8):
  
  • Elevated perching opportunities above perceived threats.
  • Ample visual barriers (live or artificial plants) to reduce stress.
  • Chronic stress is a major problem.
    
    • Many common dz (candidiasis, asper, mycobacteriosis, atoxoplasmosis) are considered to be caused by opportunistic pathogens, assoc with immunosuppression from chronic stress.
  • Species specific temp, social dynamics, lighting, photoperiod, diets.
  • Nesting materials should avoid fine synthetic fibers/materials known to cause entanglement or leg constriction.
  • Small enclosures with wire mesh are known to cause feather damage (retrices and remiges).
  • Small enclosures if needed for transport should have smooth, solid walls vs wire mesh.

MMWS

• Ensure caging won’t cause feather damage
• Adult passerine BMR 65% higher than larger non-passerine species
• Other species with torpor – swifts, swallows, nightjars
  
  • Maintenance fluid volume during rehydration (typically birds 100ml/kg/d, some passerines 250-300ml/kg/d)
  • Easily imprinted species – corvids (jays, crows), galliform chicks

Question 32

How do birds thermoregulate?

Why are they more susceptible to heat stress?

What are the primary gross and clinicopathologic changes associated with heat stress in Australian doves and budgerigars?

Answer 32

• Birds thermoregulate physiologically (e.g dermal capillary dilation) or behaviorally (e.g. wing venting, gular fluttering)
• Birds are more susceptible to heat stress because they have high body temps, high metabolic rates, and rely on evaporative cooling
• Heat stress typically causes congestion, hemorrhage, thrombosis
• Congestion and lymphoid aggregates in liver, lungs, kidneys, and/or intestine were common in all groups
• Primary organ affected differed by species
• Lung congestion most common overall
• Myocardiocyte vacuolation and airway hemorrhage were only seen in doves
• Clinicopathologic changes varied by species and heat:
  
  • Budgies: increased heterophils and decreased PCV
  • Doves @ 35 C: decreased eosinophils

JAMS 2020. Organ Histopathology and Hematological Changes Associated With Heat Exposure in Australian Desert Birds

Question 33

Describe your preventative medicine plan for passerine birds

Answer 33

• Preventive Medicine (F8):
  
  • Proper husbandry to reduce stress and work toward preventing dz exacerbated by immunosuppression.
  • Quarantine usually a minimum of 30 days.
    
    • Screening for atoxoplasmosis, mycobacteriosis, salmonellosis, and chlamydiosis may be warranted.
    • Regular wt checks and exams.
      
      • Can be conditioned to perch on scales to minimize stress.
  • Perform exams and diagnostics efficiently.
  • Necropsy and histo should be performed on all dead individuals.

Question 34

Describe the differences between alfaxalone only, alfaxalone + midazolam, and alfaxalone + butorphanol anesthesia in the Bengalese finch.

Answer 34

• Significant dose-dependent increases in the duration of anesthesia for dose response trial
• Alfax midaz resulted in significantly faster induction compared with both alfaxalone and Alfax torb
• Righting times statistically longer and slower recovery for AM and AB groups than for A alone
• Only AM had statistically significantly lower pulse rates compared with A alone
• Apnea was not observed in any animal
• Minimal dose-dependent reductions in response to noxious stimulation of the phalanx
• Addition of midazolam but not butorphanol reduced responses to noxious stimuli
• AM reached maximal muscle relaxation quicker (leg- 10 min; wing- 15–20 min) than AB (leg and wing - 25 min) and was slightly more effective in reducing muscle tone
• Duration was similar for both AB and AM, with effects wearing off 40 min and lasting on average 85–90 min

Perrin, K. L., Nielsen, J. B., Thomsen, A. F., & Bertelsen, M. F. (2017). Alfaxalone anesthesia in the Bengalese finch (Lonchura domestica). Journal of Zoo and Wildlife Medicine, 48(4), 1146-1153.

Question 35

What is the most important cause of wild passerine mortality?

Answer 35

• Trauma
• Most important cause of mortality
• Collision with window glass (est. 600 million birds yearly), turbines (134-230,000 yearly)
• Fireworks disturb flocks.
• Predation- cats (Est. 1 billion/year). Pasteurella multocida septicemia.

Terio

Question 36

Avian Keratin Beak Disorder is caused by what virus?

Are any species over-represented?

Answer 36

A novel picornavirus (poecivirus)

Poecivirus is present in individuals with beak deformities in seven species of North American birds.

Zylberberg M, Van Hemert C, Handel CM, Liu RM, DeRisi JL.

Journal of Wildlife Diseases. 2021;57(2):273-281.

Background

• Recent epizootic of avian keratin disorder (AKD) in North America and EU
  
  • Beak deformities: elongation +/- crossing and marked curvature
  • First observed in Alaskan Black-capped chickadees (Poecile atricapillus) late 90’s (prev 6.5%)
  • Also clinical signs in > 40 avian species esp corvids, cavity-nesting passerines, and raptors
  • Appears to cluster geographically
• Poecivirus: novel picornavirus, identified with metagenomics in beak tissue from BCC
  
  • All 28 affected tested positive, only 9/96 asymptomatic tested positive
  • In situ hybridization and strand-specific expression assay used to localize poecivirus to beak tissue of positive animals and show active viral replication

Conclusions

• Poecivirus previously associated with avian keratin disorder in black-capped chickadees was also identified in 6 other avian species via PCR of cloaca and beak tissue. Metagenomics in these individuals failed to identify any other pathogens that might be associated.

Terio - new article in JWD too

Question 37

Lymphoma is common in which passerine birds

Answer 37

Finches & canaries

Terio

Question 38

Describe the two forms of avian pox.

Answer 38

• Cutaneous form – Most common presentation. Proliferative skin lesions around non-feathered skin and cere.
  
  • Proliferative lesions 7-9 days post infection
  • May be self limiting, although surgical removal may be necessary if interfering with eating, drinking, or respiration.
  • Supportive care and abx to control secondary infections may also be warranted in some cases.
• Diphtheritic form - fibrinonecrotic, plaquse, pseudomembranous; common in canaries; oral cavity, trachea, lungs and air sacs most commonly affected.
• Fowler 8 also mentions a rare systemic form

Terio

Question 39

What type of inclusion bodies occur with avian poxvirus infection?

Answer 39

Eosinophilic intracytoplasmic inclusion bodies called Bollinger bodies

Terio

Question 40

Describe the main forms and species of avian pox.

What effect does avian pox have on naive populations when introduced through illegal trade or invasive species?

Answer 40

Suepaul, R. B., Seetahal, J. F., Oura, C., Gyan, L., Ramoutar, V. V., Ramkissoon, V., … & Carrington, C. V. (2019). Novel poxviral infection in three finch species illegally imported into trinidad, west indies, with implications for native birds. Journal of Zoo and Wildlife Medicine, 50(1), 231-237.

• Avian poxviruses (avipoxviruses) – Poxviridae family.
  
  • Dry/cutaneous form manifests in unfeathered areas, wet/diptheritic form manifests as necrotic caseous membrane in upper resp tract, mouth, pharynx. Viremic form has also been described, results in high mortality.
  • 10 spp of poxvirus currently recognized – Fowlpox, Canarypox, Juncopox, Mynahpox, Psittacinepox, Sparrowpox, Starlingpox, Pigeonpox, Turkeypox, Quailpox.
    
    • Three main clades – A fowlpox, B canarypox, C Psittacinepox.
  • Interferes with flight ability, reduces endurance, results in ataxia and weakness making them susceptible to predation.
• Can be devastating to naïve bird populations.
• In all three finch spp in this report, gross lesions were consistent with cutaneous form of the disease with 1-5 mm nodules on nonfeathered areas.
• The presence of Bollinger bodies, epithelial hyperplasia, hypertrophy, and ballooning degeneration confirmed poxviral infection on hiso.

Question 41

Avianpox is more common in managed or wild birds? Why?

Is there a seasonality to this disease?

Answer 41

Le Net, R., Provost, C., Lalonde, C., Régimbald, L., Vézina, F., Gagnon, C. A., & Lair, S. (2020). Whole genome sequencing of an avipoxvirus associated with infections in a group of aviary-housed snow buntings (plectrophenax nivalis). Journal of Zoo and Wildlife Medicine, 50(4), 803-812.

• Lower occurrence in captive birds compared to free-ranging ones likely due to lower exposure to blood-sucking or biting arthropods which are believed to be the main route of transmission
• Most cases were in the fall, which follows the summer season with high abundance of mosquitos. Captivity increased bird-to-bird contact due to their confinement. Stress associated w/ captivity and handling for the research project
• Snow buntings (Plectrophenoax nivalis) apparently susceptible

Question 42

Avian mycobacteriosis is most commonly caused by which Myco species?

Answer 42

M. avium, M. intracellulare, M. genavense

Terio - Passerine Chapter

Question 44

What are the lesions observed with Avian Mycobacteriosis in passerine birds?

Answer 44

Granulomatous inflammation in the GI, liver, spleen, bone marrow, lung

Vascular form in fairy bluebirds causing aortitis and cardiopulmonary arteritis

Often presents with a marked leukocytosis

Question 45

What is the morphology of mycobacteria?

Answer 45

Non-motile, spore forming, gram variable, acid-fast positive bacili

Terio

Question 46

What is the most common salmonella serovar in passerine birds.

What clinical signs and lesions are associated with it?

What is a common source of infection in wild passerines?

Answer 46

• Common cause of mortality in passarines: songbird salmonellosis
  
  • Most: Salmonella enterica subsp. Enterica serovar Typhimurium
  • Sudden death, ataxia, poor flight, ingluvitis, crop abscesses, emaciation, arthrosynovitis (MMWS).
  • Fecal oral transmission on tray feeders.
• F8 – Salmonella tymphimurium most often assoc with clinical dz.
  
  • Diarrhea and nonspecific signs of disease.
  • May be variable and intermittent.
  • Septicemia may occur with multi organ lesions.
  • Wt loss, hepatosplenomegaly, necrotic inflamed pale foci in the GIT and other organs.
  • Tx difficult and may result in creation of subclinical carriers.
  • Outbreaks assoc with bird feeding stations.
    
    • Efforts should be taken to minimize fecal-oral contamination.
  • Yersinia pseudotuberculosis causes similar CS and gross lesions, may be differentiated through bacterial cultures.

Question 47

What passerines are most at risk of salmonellosis

Answer 47

Seed eating species

Fowler 6

Question 48

What lesions are found post-mortem in passerines that have died from Salmonellosis?

Answer 48

• Very thin (loss of 1/3 of normal body weight), enlarged liver and spleen often with small, pale foci on external and cut surface, many organs affected (air sacculitis, pericarditis, ulcerations or granulomas of the esophagus and intestine, CNS/joints/eyes affected)
• Greenfinches will often get necrotic ingluvitis with large yellow swellings in wall of crop can appear as crop stasis (thin with a full crop)

Fowler 6

Question 49

Treatment of passerine salmonellosis is controversial.

What preventative measures are recommended instead?

Answer 49

• Keep captive and wild populations separate
• Quarantine with fecal screening
• Avoid crowding at food sites where food can be contaminated with feces
• Suggestions:
  
  • Multiple feeding stations (to avoid huge crowd at one), change food out regularly
  • Clean the ground often to clean up food and feces
  • Clean the surfaces that birds are eating off of (5% bleach)
  • Change out water
• Store food so no contamination by rodents

Fowler 6

Question 50

Conjunctivitis in wild passerines is most likely caused by what organism?

What species are particularly susceptible? Which may be potential reservoirs?

How is this organism transmitted?

Answer 50

• Mycoplasma spp.
  
  • M. meleagridis, M. synoviae, and M. gallisepticum
  • M. sturni – conjunctivitis with focal mucosal ulceration in blue jays, mocking birds, and starlings. F8 – This bacteria may also be found in individuals without clinical disease, so its role in the dz remains uncertain.
  • F8 – Mycoplasma gallisepticum is the causative agent of mycoplasmal conjunctivitis in passerines.
    
    • Primarily associated with wild house finches (Carpodacus mexicanus), other spp.
    • American goldfinches (Spinus tristis) may be subclinically infected and may serve as potential reservoirs.
  • Periocular (infraorbital sinus) swellings, upper resp tract exudate that may form a dried crust on the head and face. May lose vision and starve.
  • Transmission both vertical and horizontal, through direct contact, aerosol, fomites.
  • MMWS:
    
    • Mycoplasma gallisepticum – immature house finches, American gold finches, blue jays, other; platform feeders associated with disease (want feeders with small holes that birds can’t perch in the food)
    • Conjunctivits, periocular inflammation/swelling, dyspnea, sinusitis, secondary bacterial conjunctivitis and ocular discharge
    • Topical abx, may become subclinical carrier; check with state regulations for release

Question 51

What is the predominant species of Mycoplasma to affect corvids (in Germany)?

What age groups or classes are most likely to display clinical signs?

Answer 51

M. struni (7% of healthy population, 31% of rehabilitated individuals)

Juveniles or emaciated/injured adult birds - may be immunocompromised allowing the mycoplasma to produce disease

Ziegler, L., Palau-Ribes, F. M., Schmidt, L., & Lierz, M. (2017). Occurrence and relevance of Mycoplasma sturni in free-ranging corvids in Germany. Journal of wildlife diseases, 53(2), 228-234.

Question 52

What morphometrics can be used to ascertain the severity of disease in passerine mycoplasmosis?

Answer 52

Key Points:

· Mycoplasma gallisepticum

o Causes severe conjunctival inflammation of passerine birds

o Large die-off of House Finches (Haemorhous mexicanus) on the east coast of the US

o Several visual scoring systems have been proposed – most having a four-point scale from 0 (no pathology) to 3 (severe pathology) with half points

· This study

o Used geometric morphometrics to assign points around the eye and analyze phenotypes throughout the course of disease

o Eyes moved through a predictable pattern of progression based on severity

o Exudate was a weak indicator during infection with the low virulence isolate, but crusting was a strong indicator during infection with the high-virulence isolate – so crusting could be used as a prognostic indicator

Journal of Wildlife Diseases, 57(3), 2021, pp. 525–533

USING MULTIVARIATE ANALYSES TO EXPLORE DISEASE PROGRESSION OF FINCH MYCOPLASMOSIS

Rachel M. Ruden, Dean C. Adams, and James S. Adelman – Reviewed by MSM

Question 53

Erysipelothrix rhusiopathiae is a concern in which endangered passerine?

Answer 53

The Hawaiian crow (Corvus hawaiiensis)

Question 54

Describe the clincial signs associated with candidiasis in passerine birds.

What treatment options are available?

Answer 54

• Candidiasis
  
  • Common in passerines
  • Opportunistic, usually concurrent disease present
  • F8 – Candida albicans and other spp.
    
    • Likely part of the normal GI flora but opportunistic overgrowth may cause significant dz.
      
      • Oral or esophageal plaques, crop stasis, diarrhea, regurgitation, and death.
      • Problem with significant mortality in nestlings.
      • Dysbiosis and secondary overgrowth possibly from chronic stress, abx use, and concurrent dz.
    • Gram stain of feces can be used for noninvasive monitoring.
    • Apple cider vinegar has been added to drinking water of passerines to acidify the GI and inhibit yeast proliferation for mild overgrowth.
    • Antifungal tx may be warranted with worse infections.

Terio

Question 55

Describe the anatomic location avian gastric yeast most commonly occurs.

What passerine species appear particularly affected?

Answer 55

The GIT - particularly the gastric isthmus

CS - undigested seeds in droppings, diarrhea, weight loss, death

Finches and canaries commonly affected

Treat with amphotericin B, nystati, fluconazole

Question 56

What nematode causes verminous encephalitis in passerine birds

Answer 56

Chandlerella quiscali - the Grackle Nematode

transmitted by mosquitoes, may have a role in

Question 57

What nematode commony casues debilitation and mortality in passerine species due to proventriculitis?

Answer 57

Synthimantus (Dispharynx) nasuta

Transmitted through terrestrial isopods

(Terio)

Question 58

What is the tracheal mite?

What passerine birds does it commonly affect?

Question 59

Describe the transmission, clinical signs, and gross lesions of systemic isosporosis in passerine birds.

Answer 59

• Transmission is fecal-oral.
  
  • Asexual replication (merogony) within intestinal epithelium.
  • Followed by gametogony, fertilization, and shedding of unsporulated oocysts within feces.
  • Oocysts sporulate within environment and become infectious.
  • In species causing systemic (visceral) dz – extraintestinal meogony common within circulating MN cells and gametogeny may occur (rarely).
    
    • Circulating cells may serve as source for reinfection and shedding.
    • LC likely direct, vertical transmission suggested in some cases.
    • Potentially also insect vectors.
• Clinical Signs and Lesions:
  
  • May not show clinical signs.
  • CS – nonspecific, ruffled feathers, dyspnea, tachypnea, anorexia, hyporexia, wt loss, diarrhea, dehydration, death.
  • Juvenile and fledgling birds most susceptible.
  • Gross – splenomegaly*, foci of necrosis or inflammation in spleen and liver, thickened or dilated intestines, enlarged darkened liver, pale streaks within heart and skeletal muscle.
    
    • Darkened liver aka black spot because it can be viewed through body wall.
    • Dx – Impression smears of spleen, lung, liver may show lymphocytes and histiocytes or oval-shaped intracytoplasmic pale basophilic to eosinophilic merozoites surrounded by a colorless capsule (parasitophorous vacuole) that indents the nucleus.
  • Histo – vascular and perivascular inflammation and necrosis.
    
    • Spleen, liver, heart, lung, intestine.
    • Infected MN cells may adhere to blood vessel endothelium within lung.
    • Impression smears critical for diagnosis – difficult to see on histo.
    • Concurrent infections and stress may contribute to mortality.

Fowler 9

Question 60

How is systemic isosporosis definitively diagnosed?

Answer 60

• Gold standard – impression smears of visceral organs – spleen, liver, lung.
• May see larger single merozoites within a single parasitophorous vauole (waiting merozoite) and multiple smaller merozoites sharing a common parasitophorous vacuole (proliferative merozoites).
  
  • Merozoite within MN cells cause the characteristic appearance of indentation in the nucleus.
  • Not useful to screen live birds.
    
    • Cytology of whole blood and buffy coat smears may ID merozoites.
    • May ID organisms in feces if shed, but intermittent.
    • PCR.

Fowler 9

5 consecutive dialy fecal samples for PCR deteciton - Jaime’s paper

Question 61

Describe the sensitivity of qPCR in detecting systemic isosporosis in passerine birds.

Answer 61

Submission of five consecutive daily samples has an diagnostic sensitivity of 0.86.

JZWM 2020. A qPCR assay and testing guideline for the molecular diagnosis of systemic isosporosis (formerly atoxoplasmosis) in passerine birds. Landolfi et al.

Question 62

Is there any seasonality to mortalities with Systemic Isosporosis?

Any physical examination abnormalities that may be identified?

What age groups are most commonly affected?

Answer 62

• 90% of birds died between Aug-Dec, seasonal
• Season had a significant effect with most deaths observed in autumn and winter
  
  • Molting occurs during that time; additional physiologic stressor - potential to suppress immunocompetence
• Most birds showed clinical signs before death. Hepatomegaly and pectoral muscle myositis
  
  • Significant correlation between liver silhouette measurement and the % of infected lymphocytes
• Most common postmortem: splenomegaly (100%), then hepatomegaly and multifocal foci in pectoral muscles and heart
• Histopath: lymphohistiocytic inflammation in organs with merozoites.
• Age predilection was seen with birds 1 - 4 years (most common 1-2 yrs) of age having the highest % mortality

Barbón, A. R., López, J., Jamriška, J., Thomasson, A., Braun, J., & Stidworthy, M. F. (2019). Clinical and pathological aspects of systemic Isospora Infection in Blue-crowned laughing thrushes (Garrulax courtoisi) at Jersey Zoo. Journal of avian medicine and surgery, 33(3), 265-277.

v

Question 63

What is the effect of toltrazuril on systemic isosporosis.

Answer 63

PO toltrazuril 25 mg/kg may be effective in reducing shedding after one week (study not carried out further).

This study also suggested there may be transovarian transmission of systemic isosporosis.

Mohr, F., Betson, M., & Quintard, B. (2017). Investigation of the presence of Atoxoplasma spp. in blue-crowned laughingthrush (Dryonastes courtoisi) adults and neonates. Journal of Zoo and Wildlife Medicine, 48(1), 1-6.

Question 64

In a recent retrospective on Mycobacterium genavense infections in avian species, what were the most common clincial signs?

What were the most common radiographic findings?

What were the most common gross findings?

Were any coinfections thought to be significant?

Answer 64

• Common species - budgerigars (34%), zebra finches (12%), Eurasian goldfinches (6%), vitelline masked weavers (6%), red-fronted parakeets (6%), and canaries (5%)
• Most common clinical signs - feather disorders (31%), dyspnea (28%), ocular manifestations (20%), brittle beak and/or claws (20%), falling over or falling from the perch (20%), and polyuria (16%)
• Most common radiographic findings - loss of the hourglass waist of cardiohepatic silhouette (76%), shadowing of the lungs (60%), shadowing or displacement of air sacs because of enlarged liver shadow (60%), displacement of ventriculus (51%), prominent kidneys (49%), and arthrosis (35%). 22% showed signs of osteolysis.
• Half had only minor to no gross necropsy lesions
• Main gross pathologic findings - hepatomegaly (46%), dilated intestines (37%), and reddish wet lung (27%). Nodules found in 21% of birds
  
  • 4% of birds had only local lesions of eyes (subconjunctival granulomatosis)
• Coinfections with circovirus, polyomavirus, and M ornithogaster associated with greater risks of several pathologic lesions and clinical signs. Birds with polyomavirus more likely to have feather disorders.

Schmitz, A., Rinder, M., Thiel, S., Peschel, A., Moser, K., Reese, S., & Korbel, R. (2018). Retrospective evaluation of clinical signs and gross pathologic findings in birds infected with Mycobacterium genavense. Journal of avian medicine and surgery, 32(3), 194-204.

Question 65

Tibiotarsal fractures in small birds can be treated with tape splints.

Is there a size cutoff?

Are there any risk factors for an unsuccessful outcome?

Answer 65

The findings of this study indicated that a tape splint is an appropriate means for treatment of tibiotarsal fractures in birds weighing less than 200 g.

• Based on this study, proximal tibiotarsal fx can sufficiently be stabilized with tape splint.
• Three factors significantly assoc with increased risk for an unsuccessful outcome:
  
  • Lack of deep pain at initial exam, dog or cat attack as cause of fx, splint removal before 14 days after initial placement.

Wright, L., Mans, C., Olsen, G., Doss, G., Amene, E. W., Britsch, G., … & Heatley, J. (2018). Retrospective Evaluation of Tibiotarsal Fractures Treated With Tape Splints in Birds: 86 Cases (2006–2015). Journal of avian medicine and surgery, 32(3), 205-209.

Question 66

What was the effect of the introduction of West Nile virus on California populations of the Yellow-Billed Magpie (Pica nutalli)?

Answer 66

• No sig difference in heteroxygosity, inbreeding, allelic richness among time points
• Low genetic diversity overall, but did not change as a result of WNV
  
  • Lower than when compared to other endangered corvid species (Island and Florida Scrub Jays)
  • But inbreeding and relatedness were low
• Presence of two genetic bottlenecks, likely the same bottleneck that was detected at two different time points rather than two unique bottlenecks
  
  • May have been associated w/ extreme draughts in California at the time
• This species has communal roosts w/ high density of birds and low dispersal rates à could allow persistence of virus in population

Take-home: WNV did not affect genetic diversity of Yellow-Billed magpies (endangered corvid species), but were found to have low genetic diversity even before WNV = conservation concern

Vazquez, A., Gustafson, K. D., Harmeling, B., & Ernest, H. B. (2019). Genetic diversity of yellow-billed magpies (pica nutalli) before and after a west nile virus epidemic. Journal of wildlife diseases, 55(2), 316-324.

Question 67

What group of passerines will have lysis of RBC if blood samples are placed in EDTA?

Answer 67

Corvids

Fowler 8

Question 68

What is the predominant leukocyte of passerine birds?

Answer 68

Lymphocytes

Fowler 8

Question 69

Cape sugarbirds (Promerops cafer) ingesting homemade xylitol nectar displayed what clinical signs?

What findings were present on necropsy?

List three taxa that can ingest xylitol safely (due to breakdown by gut bacteria).

List three with reported toxicity.

Answer 69

CS - incoordination, weakness, falling over, collapse, death

Severe hepatic and pancreatic necrosis, congestion of cardiac, pulmonary, and meningeal tissues.

No problem - people, horses, rats, rhesus monkeys

Toxic - dogs, goats, rabbits, cows, babboons

Gardner, B. R., & Mitchell, E. P. (2017). Acute, fatal, presumptive xylitol toxicosis in Cape Sugarbirds (Promerops cafer). Journal of avian medicine and surgery, 31(4), 356-358.

Question 70

What dangers exist in surgical removal of thymomas in passerine birds?

Describe the origin and behavior of thymoma neoplasia.

What clincal signs exist?

What is the treatment of choice?

Answer 70

• Fatal hemorrhage (proximity to jugular vein)
• Thymus contains a small number of B lymphocytes – can function as a secondary lymphoid organ in birds
• Thymomas
  
  • Tumors derived from the epithelial component of the thymic, with varying degress of nonneoplastic lymphocytes
  • 65% are benign, 35% are invasive
  • Clinical signs usually due to space occupying effects
  • Paraneoplastic syndromes – myasthenia gravis, hypercalcemia, polymyositis, cytopenia, dermatitis – reported in dogs, cats, and people but not in birds
  • Treatment of choice is surgical excision
  • Radiation is useful for invasive thymomas

Urraca, V. H., Salinas, E. M., González, E. C., & Godoy, F. D. S. (2018). Mixed Thymoma in an American Robin (Turdus migratorius). Journal of avian medicine and surgery, 32(3), 226-231.

Question 71

Describe the antomy of the avian stifle joint.

Describe the procedure of stifle disarticulation of hindlimb amputation.

Compare this procedure with other amputation methods in small birds.

Are there any negative prognostic indicators to consider in deciding whether to pursue this procedure?

Answer 71

• Anatomy of the avian stifle joint:
  
  • Distal articular condyles of the femus, patella, fibular head, proximal tibiotarsus.
  • Soft tissue – cranial/caudal cruciates, joint capsule, paterllar ligaments, med and lat collateral ligaments, 2 menisci.
  • Tibial and fibular nerves lateral to the joint.
  • Avian stifle joint:
  • 3 joints – femoropatellar joint, femorotibial joint, femorofibular joint.
    
    • Femorotibial joint main wt bearing.
• Procedure:
  
  • Circumfrential skin incision, distal to stifle.
  • SQ tissues bluntly dissected.
  • Circumferential modified Miller’s knot distal femur encircling muscle bellies and occluding vasculature distally.
  • Femorotibial joint disarticulated, distal structures removed.
  • Muscle and skin was apposed.
  • Advantages:
    
    • Decreased surgical and ax time.
    • Simple, reduced blood loss, less trauma to soft tissue structures.
    • Lack of required bone and muscle sectioning.
    • May produce a longer lever arm for proprioception and balance.
    • Shorter ax time.
    • No risk of entering air sac diverticula vs mid-femoral.
• Discussion:
  
  • Alternative to transfemoral amputation.
  • Most common sites for pelvic limb amp – transection of the proximal TMT and midfemur.
    
    • TMT technique provides stump for moderate wt bearing.
    • Midfemoral provides sufficient soft tissue for closure and prevents self-trauma to the amputated limb.
  • Through-the-knee amputation superior in humans.
  • Pneumatization of appendicular skeleton.
    
    • Most birds – sternum, scapula, humerus, femur, pelvis, thoracic vert contain diverticula of the air sacs.
  • Monitor for contralateral pododermatitis.
  • Negative prognostic indicators of pelvic limb amputation in birds:
    
    • Obesity, degenerative changes in opposite limb, disorders affecting the wing which become crucial for balance.
    • This procedure better for small birds.

Ozawa, S., & Mans, C. (2017). Stifle disarticulation as a pelvic Limb amputation technique in a Cockatiel (Nymphicus hollandicus) and a Northern Cardinal (Cardinalis cardinalis). Journal of avian medicine and surgery, 31(1), 33-38.

Question 72

What is the air sac nematode of passerine birds?

What is the air sac nematode of falcons?

How are these diagnosed? What clincial signs exist? How are they treated?

Answer 72

Diplotriaena – large nematodes from superfamily Diplotriaenoidea, inhabit air sacs of birds.

• Females produce thick shelled eggs -> L1 near ostium of air sacs, migrate to resp system via pharynx, coughed, swallowed, passed in feces.
• Insects eat eggs, hatch in gut, then in IM host penetrate gut and lodge into body, 2 molts -> L3.
• L3 migrate from gut and develop in hepatic portal system, migrate to lungs as late L4 or subadult worms via heart and pulmonary arteries, then lungs, then air sacs.
• Dx in live birds via detection of eggs in feces. CS of resp disease may not be apparent.

Serratospiculum spp in falcons also in same Diplotriaenoidea superfamily.

• Air sacculitis and pneumonia.
• Inflammation assoc with number of eggs and parasites, but no change may be seen with adults in the air sac.
• Serratospiculum amaculata – significant pathologic changes throughout air sacs, lungs, liver, PV, myocardium and death with severe infection.
• Tx in falcons with ivermectin, removal of dead nematodes via endoscopy may be best to avoid significant inflammation associated with necrotic worms.

Gosbell, M. C., & Luk, K. H. (2019). Diplotriaena—An Air Sac Nematode Found in a New Holland Honeyeater (Phylidonyris novaehollandiae). Journal of avian medicine and surgery, 33(2), 189-192.

Question 73

A recent study evaluated the seroprevalence of influenza in Thailand.

What strain were they concerned about? What species were most affected? Why is Thailand an area of concern?

Answer 73

• HPAIV H5N1 – significant zoonotic disease of Eurasia & Africa
• Thailand has large areas of wetlands or rice fields that are suitable migratory waterfowl habitat
• 1.32% seroprevalence for the virus
  
  • Most common positives – Asian openbill, lesser whistling duck, streak-eared bulbul
  • Passerines actually had the highest seroprevalence suggesting transmission to wild birds from migrating waterfowl
• Asymptomatic AIV infection has been reported in waterfowl & gulls – they may warrant more careful monitoring

Poltep, K., Ketchim, N., Paungpin, W., Prompiram, P., Sedwisai, P., Chamsai, T., … & Ratanakorn, P. (2018). A long-term serosurvey of avian influenza h5 among wild birds in nakhon sawan province, thailand. Journal of Zoo and Wildlife Medicine, 49(2), 464-469.

Question 74

What is the gold standard of avian influenza diagnosis?

How does the ELISA compare?

What sort of response to various orders of birds have to vaccination with inactivated European products?

Answer 74

Journal of Zoo and Wildlife Medicine, 48(3): 882-885. EVALUATION OF A COMMERCIAL COMPETITIVE ENZYME-LINKED IMMUNOSORBENT ASSAY FOR DETECTION OF AVIAN INFLUENZA VIRUS SUBTYPE H5 ANTIBODIES IN ZOO BIRDS

Hemagluttination Inhibition

• Various bird species vaccinated twice with inactivated H5N9 AI vaccine 6 wk apart
  
  • Accipitriformes, Anseriformes, Charadriiformes, Ciconiiformes, Coraciiformes, Galliformes, Gruiformes, Pelecaniformes, Phoenicopteriformes, Psittaciformes, Sphenisciformes, Strigiformes, and Struthioniformes
  • Blood samples collected prior to 1st vaccination and 4–6 wk after 2^nd vaccination
  • HI performed with H5N1, H5N2, and H5N7 antigens and competitive H5 antibody ELISA performed
• ELISA - specificity 94.2 % and sensitivity 93.9 %
  
  • best specificity and sensitivity was obtained for Galliformes
  • lowest specificity and sensitivity in Sphenisciformes, followed by Phoenicopteriformes
• Vaccination Responses
  
  • Penguins, pelicans, guinea fowl, and Inca terns showed poor vaccination response
• Conclusion – ELISA for detection of H5 AIV antibodies demonstrated a strong agreement with HI testing and a high sensitivity and specificity across many avian species

Question 75

Discuss the differences between plasmodium and haemoproteus in avian species.

What is the prevalence of these diseases in wild birds in Asia?

How is diagnosis achieved?

Answer 75

Rhim, H., Bae, J., Kim, H., & Han, J. I. (2018). Prevalence and phylogenetic analysis of avian haemosporidia in wild birds in the republic of korea. Journal of wildlife diseases, 54(4), 772-781.

· Plasmodium and Haemoproteus species

o Common worldwide

o Transmitted by biting arthropods of genera Culex, Aedes, Hippobosca, and Culicoides

o signs - anemia, emaciation, loss of appetite, difficulty in breathing, lameness, reduced Reproductivity, death

o Lesions - enlargement of the liver, spleen, and kidneys

o Haemoproteus only infects erythrocytes but Plasmodium can penetrate leukocytes or platelet as well

o Pigmented granules and shape and location of nuclei diagnostic features of Plasmodium

· 36% positive for avian haemosporidia on blood smears, 45% positive by PCR targeting the cytochrome b gene

· 89% identified as Haemoproteus spp. and 11% as Plasmodium spp on PCR

· 33% of resident birds and 21% of winter migratory birds infected with avian haemosporidia

· For diagnosis, recommend looking both at blood smear and doing PCR

o PCR may be more sensitive for low parasitemia

· Cross-infection between wild birds, including transmission from migrants to residents, observed

Question 76

Describe the acute phase response and how helminths alter this response.

How does intestinal helminth infection in passerine birds affect this response and does it change susceptibility to other pathogens?

Answer 76

Vaziri, G. J., Muñoz, S. A., Martinsen, E. S., & Adelman, J. S. (2019). Gut parasite levels are associated with severity of response to immune challenge in a wild songbird. Journal of wildlife diseases, 55(1), 64-73.

• Acute phase response (APR)
  
  • Immune response triggered by diverse micro- parasites
  • Involves activation of Toll-like receptors –> induction of proinflammatory cytokine signaling > production of antimicrobial peptides
  • Whole-body responses > fever, lethargy, and anorexia
• Helminths alter host immune response
  
  • By induction of T regulatory cells, > dampen proinflammatory signaling > biasing helper T cells (Th) toward type 2 (Th2) phenotypes
  • Th2 phenotypes > production of anti- inflammatory cytokines, including interleukin (IL)-3, -4, -21, & -25
    
    • Facilitate immune response to extracellular parasites & production of specific Ab
    • Secreted cytokines respond to microparasites such as bacteria and viruses
• Higher gut helminth infections did lead to dampened APR responses to innoculation with LPS (bacterial infection) but did NOT affect susceptibility to malarian parasites

Question 77

Describe the lipid and biochemical profiles of the common mynah (Acridotheres tristis) in comparison to other birds.

Answer 77

Jahantigh, M., Zaeemi, M., Razmyar, J., & Azizzadeh, M. (2019). Plasma Biochemical and Lipid Panel Reference Intervals in Common Mynahs (Acridotheres tristis). Journal of avian medicine and surgery, 33(1), 15-21.

Takeaway: lipid profile of common mynahs is similar to other birds and serum ALP/LDH/CK may be higher than in other species (canaries, starlings, toucans)

Question 78

Describe the fecal flora of passerine birds (study was in Australia).

Answer 78

Latham, B., Leishman, A., Martin, J., & Phalen, D. (2017). Establishing normal fecal flora in wild Australian passerine birds by use of the fecal gram stain. Journal of Zoo and Wildlife Medicine, 48(3), 786-793.

• Conclusions:
  
  • Wild Australian passerines from central New South Wales in spring and summer should only have gram-positive bacteria in their fecal Gram stains
  • Most birds will only have few or moderate numbers of bacteria in their feces
  • Fecal bacteria concentrations and proportion of different cocci, coccobacilli, and rods likely affected by bird species and diet
  • Yeasts rarely seen in these wild passerines with exception of bell miner and noisy miner
  • Macrorhabdus ornithogaster does not appear to be naturally present in these species

Question 79

Describe the role of wild birds as a source of antibiotic-resistance enterococcus.

Answer 79

Stępień-Pyśniak, D., Hauschild, T., Nowaczek, A., Marek, A., & Dec, M. (2018). Wild birds as a potential source of known and novel multilocus sequence types of antibiotic-resistant Enterococcus faecalis. Journal of wildlife diseases, 54(2), 219-228.

• Enterococci - Part of normal microbiota of GI tract
  
  • High capacity to acquire and transfer genetic elements that confer resistance
• 27 E. faecalis isolates were resistant to at least one antibiotic
  
  • All resistant to lincomycin
  • 44% resistant to erythromycin
  • About 50% resistant to tetracycline and doxycycline
  • 22% resistant to ciprofloxacin
  • 19% resistant to streptomycin
  • 14% resistant to kanamycin
  • 4% exhibited low-level resistance to penicillin and vancomycin
  • All isolates susceptible to gentamicin and chloramphenicol
• None of van (vanA, vanB, vanC1, vanC2/C3, vanD, vanE, vanG) genes found in vancomycin-resistant isolate
• Takeaway: GI tract of wild birds constitutes a potential source of antibiotic-resistant E. faecalis
  
  • Lack of apparent host specificity in E. faecalis populations
  • High genetic diversity of isolates

Question 80

Describe euthanasia protocols for passerines in field settings.

Answer 80

Intraosseous or intravenous pentobarbital administration is recommended.

Thoracic compresion - not currently AVMA approved - but appears to cause rapid cardiac arrest.

Signs of death in birds - sudden feather erection (also sign of reduced cardiac blood flow so almost arrest)

Paul-Murphy, J. R., Engilis Jr, A., Pascoe, P. J., Williams, D. C., Gustavsen, K. A., Drazenovich, T. L., … & Engilis, I. E. (2017). Comparison of intraosseous pentobarbital administration and thoracic compression for euthanasia of anesthetized sparrows (Passer domesticus) and starlings (Sturnus vulgaris). American journal of veterinary research, 78(8), 887-899.

Question 81

How can zoos contribute to migratory bird conservation?

Answer 81

• Conclusion: Zoos can make substantial contributions to the migratory bird conservation by:
  
  • Direct and indirect support for in situ conservation.
  • Assisting in the tracking and monitoring of migratory bird populations.
  • Adoption of green practices.
  • Developing and implementing targeted educational programs and advocacy efforts.
  • Developing effective husbandry, release and translocation methods through systematic research now rather than when a spp becomes endangered.

Hutchins, M., Marra, P. P., Diebold, E., Kreger, M. D., Sheppard, C., Hallager, S., & Lynch, C. (2018). The evolving role of zoological parks and aquariums in migratory bird conservation. Zoo biology, 37(5), 360-368.

Question 82

Thymic lymphoma in birds is associated with what infectious disease?

Answer 82

• Avian thymic lymphoma
  
  • Reported in chickens
    
    • Often associated with reticuloendotheliosis virus
    • Relatively uncommon in other avian species
  • Retrovirally induced lymphoma suspected in starlings

Kruse, T., Zachariah, T., & McManamon, R. (2018). T-cell Thymic Lymphoma With Proventricular Metastasis in a Florida Scrub Jay (Aphelocoma coerulescens). Journal of avian medicine and surgery, 32(2), 128-132.

Question 83

Passerines affected with herpesviruses show what clinical signs?’

How prevalent are these viruses in wild passerines?

Answer 83

• All avian herpesviruses are alphaherpesviruses:
  
  • Marek’s disease and infectious laryngotracheitis – gallinaceous birds
  • Duck virus enteritis – Anseriformes
  • Pacheco’s disease – Parrots
  • Inclusion body or herpesvirus hepatitis – pigeons, owls, birds of prey
• Passerine HV infection causes respiratory signs (labored breathing, respiratory snicks, conjunctivitis) and high morbidity/mortality
• Low (0.76%) HV prevalence in healthy passerines via cloacal PCR swab

Question 84

Salmonella epidemics in Austrian finches have been associated with what serovar?

Are there any associated coinfections?

Answer 84

Intro

· All bird species are susceptible to Salmonella infections, but disease outbreaks are predominantly observed in passerines

· In Austria, several episodes of Salmonellarelated deaths of wild birds of the order Passeriformes, family Fringillidae, occurred during the winter months in 2010 and in 2012.

· Our study aimed to report epidemiologic data, pathologic lesions, and results of bacteriologic examination

Discussion

· The most common serovar associated with wild-bird salmonellosis is Salmonella Typhimurium, which has also been detected in healthy, free-ranging passerine birds and some gull species

· However, the overall prevalence of Salmonella in healthy wild birds appears to be very low

· Our study showed that Salmonella Typhimurium 1,4,5,12:i:1,2, phage type U277, was responsible for the mass mortality of songbirds in Austria during the winter months in 2010 and 2012.

· Most of the infected birds showed severe fibrino-purulent inflammation in the pharyngeal, ingluvial, or esophageal mucosa. In addition, there was evidence of septicemia by histologic as well as bacteriologic and IHC examination in some birds.

· These findings are largely consistent with other reports of Salmonella-associated mortalities in passerine birds worldwide

· Thought to have died due to starvation secondary to the ingluvitis/esophagitis

· Also predisposed to Macrorhabdus ornithogaster overgrowth

· Siskins may be especially vulnerable, has been documented previously

· The very high percentage (94%) of male animals in the present study is exceptional, may be due to feeding habits though a cause is unknown

MULTIPLE EPIDEMICS IN AUSTRIAN FRINGILLIDAE CAUSED BY A SINGLE VARIANT OF SALMONELLA TYPHIMURIUM

Journal of Wildlife Diseases, 57(4), 2021, pp. 891–899

Question 85

A recent study investigated the change in tissue tropism of mycoplasma gallisepticum when it jumped from poultry to house finches.

How does this disease typically present in poultry?

What about in house finches?

How did conjunctival load of M gallisepticum differ when it was inoculated from poultry rather than HOFI strains?

Answer 85

JWD 2022 58(4) 716-724
CHANGES IN TISSUE TROPISM OF MYCOPLASMA GALLISEPTICUM FOLLOWING HOST JUMP

Background:
- M. gallisepticum - causes chronic resp dz in chickens, air sacculitis, inflammation in trachea, lungs.
- Infraorbital sinusitis in turkeys
– Variability in tissue tropism is extensive - encephalitic forms in turkeys, cloacal tissue strains, unilateral eyeball enlargement strains, and keratocinjunctivitis strains in layers
– 1993-94 outbreak in House finches caused severe conjunctivitis, mucupurulennt drainage and nasal exudate; histo-lymphoplasmacytic conjunctivitis, rhinitis, sinusitis
- Poultry and house finch strains are genetically different

Take home message
- The conjunctival load of House finches inoculated with the poultry isolate of M. gallispeticum was much lower than the choanal loads in those same individuals, and compared with the conjunctival loads of birds inoculated with HOFI isolates.
- HOFI strains have simply expanded their within-host niche to the eye vs poultry ancestors
- Only eye lesions seen in the HOFI strains
- When sampling birds for infection with M. gallisepticum, it is important to test the choana and conjnctiva separately. Measuring bacterial loads in pooled samples may be misleading.

Question 86

A recent study investigated the pharmacokinetics of voriconazole in the common raven.

What is the scientific name of the raven?

What is the primary etiology of aspergillosis?
- What are typical clinical signs?

What is the mechanism of action of voriconazole?

What do the pharmacokinetics suggest regarding the dose and frequency of administration of voriconazole, both IV and PO?

Answer 86

AJVR 2022 83(10)
Single oral or intravenous administration of voriconazole achieved recommended therapeutic minimum inhibitory concentrations against Aspergillus in the common raven (Corvus corax)

Key Points:
- Aspergillus fumigatus, A. niger, A. flavus are primary fungal species implicated in avian infections (most common = A. fumigatus)
– High morbidity/mortality in birds of prey, waterfowl, penguins
– Ubiquitous fungi in environment; all birds susceptible; any organ system can be infiltrated
– Common clinical signs – respiratory distress (obstruction of syrinx, air sacculitis, fungal pneumonia), neurologic (weakness in limbs, ataxia, dysphagia), chronic weight loss, anemia
– Treatment generally protracted/expensive; high economic losses in poultry or exotic breeding farms
- Common ravens demonstrate clinical signs typical as observed in other birds; death is common
- Voriconazole PK established in many other species & demonstrates marked species variability
– Treatment of choice for aspergillosis in humans
– Triazole antifungal, synthetic derivative of fluconazole → ergosterol biosynthesis inhibitors
– Greater affinity for fungal cytochrome P450 compared to mammalian → better tolerated & less toxic than imidazoles (ketoconazole, miconazole, clotrimazole)
– MOA – inhibits ergosterol synthesis à fungal cell membranes lose fluidity & prevents cells from growing
– n=8 captive common ravens (4.4)
- IV study: All 8 administered voriconazole 10 mg/kg IV over 1 min; blood collected up to 36 hours after injection
- PO study: 4 birds given 6- and 24 mg/kg doses, 8 birds given 12 mg/kg doses via gavage; blood collected at similar time points as IV study
– Volume of distribution for single IV dose and 6 mg/kg PO dose was greater than the 12- and 24-mg/kg PO doses
– 6 mg/kg PO dose had relative bioavailability of 67.5% (exceeds values for most avian species studied to date)
- Voriconazole in other species demonstrates a nonlinear PK
– All PO doses had short half lives
– No adverse effects
– Both 5 mg/kg IV and 6 mg/kg PO doses resulted in plasma concentrations exceeding target MIC in all 3 Aspergillus species established by another study (0.5-1.0 ug/mL)

Take Home Message: Single dose of voriconazole 10 mg/kg IV or 6 mg/kg PO BID-TID is sufficient to reach target MIC for most common pathogenic Aspergillus species known to infect birds without exceeding potential toxic range (>5.0 ug/mL).

Question 87

A recent study investigated the radiographic cardiac size of the common mynah.

What is the scientific name of the common mynah?

What measurements have been used in other birds?

What measurements were useful for evaluating cardiac size in mynahs?

Cardiac width is typically what percentage of other width measurements in healthy birds?

Answer 87

Radiographic Reference Intervals for Cardiac Size in Common Mynahs (Acridotheres tristis).
Norouzi A, Mirshahi A, Razmyar J, Azizzadeh M, Nakhaee P.
Journal of Avian Medicine and Surgery. 2022;36(3):272-177.

Lit review
- Screech owls, red-tailed hawks, Canada geese: theoretical cardiac width correlated with sternal width and thoracic width - theoretical can be calculated and compared with measured
- Peregrine falcons: sternal width most precise and accurate predictor for cardiac width
- Bald eagles, Bonelli eagles, osprey: strong correlation between cardiac width and thoracic width
– Cardiac width correlation with sternal width and coracoid width was strong in bald and Bonelli eagles
- Wild galahs (cockatoo): cardiac width strongly correlated with thoracic width and coracoid width
- Medium-sized psittacines: highest association between cardiac width and sternal length
- Cardiac width should be 51-61%

Key Points
- Manually restrained, no sedation or anesthesia; cardiac width = max width of the heart, thoracic width = width of thorax at level of maximum width of the heart, synsacral width = max width
- No differentiation between inspiratory or expiratory rads
- Significant moderate correlation of cardiac width and thoracic width, coracoid width, and distance between 3rd and 4th rib
- Cardiac width was not significantly correlated with width
- Lateral views were not reliable due to superimposition of sternum and proventriculus over cardiac silhouette - VD used only
- Mynahs within the range of cardiac width reported for medium-sized psittacines (51-61%)

Conclusions
- Ratio of cardiac width:thoracic width and cardiac width:coracoid width may be suitable indices for evaluating cardiac size in the common mynah.

Question 88

A recent study evaluated the effects of dexamethasone on the hematology, hemosporidian infection, and splenic histology of house finches.

How has steroid administration affected chickens in previous studies?

What effect did dexamethasone have on the hematology of these finches?

What hemoparasites were identified in these birds? What happened to the parasite burden following the dex treatment?

What changes were seen in the spleens of treated birds?

Answer 88

J Wildl Dis. 2022 Jul 1;58(3):512-523
THE EFFECT OF DEXAMETHASONE ON HEMATOLOGIC PROFILES, HEMOSPORIDIAN INFECTION, AND SPLENIC HISTOLOGY IN HOUSE FINCHES (HAEMORHOUS MEXICANUS).
Crouch EEV, Reinoso-Perez MT, Vanderstichel RV, Dhondt KV, Dhondt AA, Cruz Otero JD, Piech T, Forzán MJ.

• Corticosteroid production in birds is regaulated by the HPA axis – impt for stress response, immune function and inflammation
• Dexamethasone is a long acting synthetic glucocorticoid that suppresses the HPA axis to a greater degree and for a longer time period in common pigeons vs mammals; also documented in turkeys and chickens
  = H:L ratios used to assess stress, with elevated ratios indicating acute stress, chronic stress
  – Racing pigeons, chickens: dex injection has induced heterophilia and lymphopenia
  – Chickens: involution of the cloacal bursa, spleen and thymus
• treated birds received dexamethasone injections for 8 days. monitored blood smears throughout the course of treatment. euthanized after tx and evaluated tissues on histopath.
• 2 birds from the treatment group and 1 control bird died prior to conclusion of the study. One definitive cause of death in the treated bird was identified - intestinal coccidiosis.
• Hematology:
  – Treated birds had a 3-fold inrcease in relative heterophils and 55% decrease in lymphocytes, when comparing day 0 and day 4 smears
  – a relative lymphocytosis was seen in the control group at day 8
  – relative eosinopenia at day 4 and day 8, when compared to d 0 counts in both the treated and control groups, only sustained by d 9 in the treated group, and represented a 50-61% decrease compared to d0 values
  – monocytes were doubled in the control group at d8 and 9 compared to d0 counts, NC in treated group.
  – in most blood smears, saw immature erythrocytes indicating mild regenerative anemia seen d/t blood collection
• Hemoparasitism
  – mean hemosporidian (Plasmodium and Hemoproteus sp) counts comparing d0 to d4 and d8 showed sig. increase
  – 36-76% infected birds in treatment group vs 0.9-3.6% in control group
  – low #s of Leukocytozoan seen only sporadically in treated birds
• Histology
  – all birds in treatment group lacked splenic lymphoid follicles sv control group (1-1+ follicles in each bird)

Take home message:
- Dexamethasone treatment appears to change the hematologic profile, natural hemoparasite infection rate, and splenic histology of House Finches.
- These changes were comptable with immunosuppresson and may mimic a stress response.

Question 89

A recent study evaluated the effects of knemidokoptiasis on the gripping position of Steller’s jays.

What is the scientific name of the Steller’s jay?

What are the three most common species of knemidokoptes? Which species do they affect?

What is the life cycle of knemidokoptes?

How prevalent was knemidokoptiasis in Steller’s jays?
- Was there a sex or age predilection?
- How did it affect their perching?

Answer 89

JWD 2022 58(4):859-868.
Knemidokoptes Mites And Their Effects On The Gripping Position Of The Feet Of Steller’s Jays (Cyanocitta stelleri)
Burris WM, Kinziger AP, Black JM, Brown RN

Background:
- Knemidokoptes spp. contains five species of avian ectoparasitic mites distributed globally
– 3-week direct life cycle; transmission via direct contact or fomites (nests, roost sites)
– Mites infest stratum corneum of the face/cere & under the scales of legs and feet
– Pathogenesis of knemidokoptiasis resembles that of sarcoptic mange in mammals
– Three most common species: K. mutans, K. jamaicensis, K. intermedius
– K. mutans commonly associated with domestic chickens
– K. jamaicensis common on wild birds globally
- Although knemidokoptiasis may cause debilitation in individual birds and is occasionally responsible for mortality, epizootic knemidokoptiasis is unlikely to have long-term effects on avian populations

Key Points:
- 27% of Steller’s Jays recorded in long-term data from this population had signs of scaly leg
– 44% of the jays captured during this study showed signs
– Wide range of prevalences reported in other avian species due to host, pathogen, and environmental factors
- No difference in prevalence between male and female Steller’s Jays
– Previous studies found higher prevalence in males
- Signs of scaly leg more common in older Steller’s Jays
– 20% prevalence in juvenile jays vs. 32% prevalence in adult jays
– Infestations may require time to develop clinical signs or not all nestlings exposed to mites will become clinically infested
- Infestation reduces ability of D2 D3 to contract, alters perching ability

TLDR: Knemidokoptes spp. is the causative agent of scaly leg in domestic and wild birds; the three most common species are K. mutans (chickens), K. jamaicensis (wild birds), K. intermedius (wild birds)

Question 90

A recent study analyzed the causes of morbidity and mortality of the blue-crowned laughing thrush.

What is the scientific name of the BCLT?

What was the number one cause of death?
- Traumatic morbidity was linked to what form of identification?

What is the second most common cause of death?
- What are the clincial signs and lesions?
- How is it diagnosed?
- How is it treated?

Answer 90

JZWM 2022;53(3):545-550
A Retrospective Analysis Of Morbidity And Mortality In Captive Blue-Crowned Laughing Thrushes (Pterorhinus courtoisi): 1998-2018
O’Connor L, Vines S, Rowden LJ, Guthrie A

Key Points:
- Most Common Cause of Death: Trauma
– Inter- or intraspecific aggression in multispecies exhibits
– Collision or entrapment in mesh in aviaries of an inappropriate size or material
– Nine trauma morbidity events were directly related to the presence of leg bands
– Training imperative for all personnel applying leg bands
– Animal care staff must regularly check that leg bands are not causing discomfort and refit or remove bands when necessary
- 2nd Most Common Cause of Death/Most Common Cause of Morbidity: Systemic Isosporosis
– BCLTs are particularly susceptible to systemic isosporosis
– Can cause hepatomegaly, splenomegaly, coelomic distention, pectoral myositis
– Causes predominantly lymphohistiocytic inflammation
– A novel species, Isospora courtoisi, has been described in BCLTs
– Transmitted fecal-orally with ova being shed in feces
– Routine fecal exams should be performed on 5-d consecutive pooled samples
– Consider secondary tests (e.g., buffy coat smears and whole blood or feces PCR)
– Often unresponsive to treatment/high mortality, particularly in neonates and juveniles
– In Europe, toltrazuril is the most frequently used anticoccidial agent in BCLTs
– Can be given orally, via gavage or in drinking water
– Exact MoA of toltrazuril against systemic isosporosis unknown
– Can be confirmed only through PCR or the presence of merozoites in lymphocytes

TLDR: Trauma and systemic isosporosis are the leading causes of morbidity and mortality in BCLTs

Question 91

A recent study described filariasis in managed grasshopper sparrows.

What is the scientific name of the grasshopper sparrow?

Describe the general life cycle of this group of nematodes.

What was the prevalence of filariasis in this population?

What diseases were correlated with filariasis?

What species was identified?

Answer 91

JZWM 2022 53(4) 755-768
IDENTIFICATION AND RETROSPECTIVE EVALUATION OF A FILARIOID NEMATODE SPECIES IN MANAGED GRASSHOPPER SPARROWS (AMMODRAMUS SAVANNARUM)

Intro/M&M
- A managed breeding program of grasshopper sparrows was established at White Oak Conservation
- Nematodes in the superfamily Filarioidea are parasites with an arthropod intermediate host and a tetrapod definitive host
- proctella stoddardi specifically has been identified in several avian species
- In this study, the phylogeny of a filarioid species was characterized and investigated as to whether the presence of this filarioid parasite was significantly correlated with subspecies, sex, body condition score, or the presence of systemic isosporosis, squamous metaplasia, coelomitis, or airsacculitis. Retrospective (n=157)

Results and discussion
- 18.5% were diagnosed with filariasis
- The age data were not normally distributed, and the median age of diagnosis was 6 mon
- No significant correlation was seen between subspecies, BCS, or sex and presence of filariasis
- Diagnosed primarily by blood films or histo
- Filariasis was significantly correlated with systemic isosporosis, coelomitis, and airsacculitis
– Co-infection with isosporosis could predispose to filariasis or vice versa
– Several sparrows had nematodes on postmortem examination in their coelomic cavities
– Nematodes were not always in the air sacs but may have migrated through
- PCR and sequencing 100% homologous with Aproctella alessandroi
- Unable to perform stats, but decrease in cases seen after the addition of mosquito netting (possible intermediate host)
- Filariasis was not considered the cause of death in any of the sparrows.