Lesson 119 - Diagnostic and viral diseases of companion birds

What are the core biosecurity practices in birds?

1. purchase from reputable sources

2. quarantine new arrivals

3. strict hygiene

4. isolate sick

5. vector control

6. prevent contact with wild birds

7. visitor control in aviaries and clinics

What is the importance of accurate sampling in diagnostics of infectious diseases?

1. health screening for biocontainment and bioexclusion

2. accurate and early sampling

3. choice of sample depends on pathogen testing and clinical signs

What are the most common tests in birds?

1. cytology (wet mount and or stain)

2. bacteriology

3. PCR

How can the respiratory tract be sampled?

1. choanal swab

2. tracheal swab

3. oropharynx swab

4. nares swab

5. conjunctival swab

6. nasal/sinus flush

7. tracheal lavage

8. swabs or biopsies of the lower trachea, air sacs or lungs via endoscopy

How can the GI system be sampled?

1. crop swab and crop flush for upper GI

2. cloacal swab and fecal sample for lower GI

What is sampling the crop essential for?

cases with vomiting/regurgitation, delayed crop emptying, or palpable abnormalities

What are the tests performed with the samples obtained from a crop swab or wash?

1. wet mount

2. gram or quick stain

3. culture and sensitivity

4. PCR

What is a fecal gram stain useful for?

detect dysbiosis or enteritis, especially in psitaccines

What should the fecal gram stain of a healthy psittacine have?

70% gram-positive rods and 30% gram-negative cocci (no gram-negative rods and yeast)

What would a switch in normal ratio, presence of gram-negative bacteria, yeast or Clostridium sp (gram-positive) indicate?

enteritis

What birds have fewer bacteria overall (mostly gram-positive)?

passerines

What birds have mostly gram-negative flora?

carnivorous birds and waterfowl

What tests are blood samples used for in birds?

1. PCR

2. serology

3. antigen detection

4. blood smear (detect parasites)

What are some other samples that are useful in birds?

1. swabs of any other lesion/exudates/discharge

2. fine needle aspirates or biopsies of organs/masses

What is postmortem (PM) examination necessary for?

definitive diagnostics to develop preventive and therapeutic strategies for the flock

How is a PM exam performed?

1. wear PPE

2. +/- fume cabinet for zoonotic disease concerns

3. examine and sample every organ

If a crop swab smear stained with Diff-Quik shows bacteria located within epithelial cells, what is the most likely diagnosis?

Ingluvitis

3 multiple choice options

What is proventricular dilation disease "PDD"?

fatal disease of psittacines caused by Avian Bornavirus (RNA virus)

How is PDD transmitted?

horizontal and vertical

What is lymphoplasmacytic ganglioneuritis?

severe immunemediated inflammatory damage to ganglia and nerves caused by PDD

What nerves are commonly affected with lymphoplamacytic ganglioneuritis?

GI tract nerves

What components of the GI tract are affected with GI tract nerve paralysis with lymphoplamacytic ganglioneuritis?

esophagus, crop, proventriculus, ventriculus

What can lymphoplamacytic ganglioneuritis impair?

peristaltic function

What can impairment of peristaltic function cause?

dilation and food accumulation in crop and proventriculus

What can inflammation of the CNS with lymphoplamacytic ganglioneuritis lead to?

CNS signs

What are the clinical signs of PDD?

1. unspecific signs like lethargy and weight loss despite normal appetite

2. undigested seeds in feces

3. vomiting/regurgitation

4. diarrhea

5. CNS signs like tremors, ataxia, seizures, blindness

What is significant about the clinical course of PDD?

1. unpredictable

2. positive birds can remain clinically healthy for years

3. clinical signs can be induced by stress

4. grave prognosis once disease develops

How is PDD diagnosed?

1. clinical signs

2. detection of enlarged proventriculus using radiography with +/- contrast

3. reduced proventriculus contractility on contrast fluoroscopy

4. crop/proventriculus biopsies for histopathology and demonstration of lymphoplasmacytic ganglioneuritis

5. RT-PCR on crop/cloacal swab

6. antibody titers against ABV in plasma

7. combination of RT-PCR + serology recommended for screening (repeated testing)

8. always rule out other causes of GI/CNS disease

9. post-mortem definitive diagnosis via histopathology and PCR

How is PDD managed?

1. test all household birds

2. birds diagnosed and treated early may return to good body condition, but life expectancy cannot be predicted

3. supportive treatment

4. NSAIDS (cox-2 inhibitors)

5. optimal husbandry, diet, avoid stress

6. hygeine and biosecurity

What is Psittacine Beak and Feather Disease (PBFD)?

1. Hemagglutinating Circovirus (DNA)

2. affect wide range of wild and captive Psittacine worldwide

3. common in pet shops/aviaries

4. difference in species susceptibility

5. horizontal transmission via feces, feather dander, regurgitation

6. massive viral excretion

What are the clinical signs of the acute form of Psittacine Beak and Feather Disease (PBFD)?

1. nestling or fledging birds especially African grey parrot, black cockatoos

2. fractures of developing feathers, intrapulp hemorrhage, oedema of wing tips (vasculitis)

3. leukopenia, anemia, green diarrhea, regurgitation, rapid death due to hepatic necrosis

What are the clinical signs of the chronic form of Psittacine Beak and Feather Disease (PBFD)?

1. gradual loss of plumage (bilateral)

2. dystrophic feathers with short, thickened/retained feather sheath, blood within calamus, constriction of calamus, fault lines across vane

3. cockatoos have loss of powder down feathers (bare skin patches, glossy beak), abnormal beak and nails (overgrown, fractures etc), skin hyperkeratosis

4. secondary infections from chronic immunosuppression

5. difficulties in eating cause hypoproteinemia, weight loss, death

How is Psittacine Beak and Feather Disease (PBFD) diagnosed?

1. clinical signs

2. leukopenia (acute form)

3. hypoproteinemia (chronic form)

4. serology

5. PCR on blood (best)

6. PCR on feathers (isolated animal only)

7. skin and feather biopsy and histology (low sensitivity)

8. postmortem examination

What are the clinical signs of Psittacine Beak and Feather Disease (PBFD)?

bilaterally symmetric feather dysplasia, beak abnormalities, etc...

How is Psittacine Beak and Feather Disease (PBFD) treated and prevented?

1. often terminal

2. supportive treatment

3. some individuals (Lorikeets, Eclectus) may recover and develop protective immunity with cessation of virus excretion

4. biosecurity for prevention

5. experimental inactivated vaccine (not available yet)

What is the virus causing proventricular dilation disease in birds?

Bornavirus

2 multiple choice options

What is avian polyomavirus (APV)?

DNA virus with an affinity for epithelial, lymphoreticular, and endothelial cells that affects mostly young psittacines

What causes "Budgerigar fledgling disease"?

avian polyomavirus (APV)

What are the clinical signs of "Budgerigar fledgling disease"?

1. acute lethargy, crop stasis, and death

2. cutaneous hemorrhage, ascites and head tremors may be seen

3. birds > 3-weeks old have delayed feathering/feather dystrophy ("runners")

4. if mild, these birds often survive

5. high mortality

6. affects 1-3 week old birds

What clinical signs of "Budgerigar fledgling disease" in other psittachines nestlings/juveniles (macaws, eclectus, conures...)?

depression, ascites, GI symptoms, bleeding, death

What is avian polyomavirus (APV) shed in?

feces, crop secretions, skin, and feather dander

How is avian polyomavirus (APV) transmitted?

ingestion +/- inhalation, horizontal and vertical

What will happen to surviving and subclinical birds with avian polyomavirus (APV)?

shed virus for months

How is avian polyomavirus (APV) diagnosed?

1. PCR

2. serology

3. postmortem histopathology and PCR

How is avian polyomavirus (APV) treated?

supportive treatment only

How is avian polyomavirus (APV) prevented?

1. biosecurity, quarantine and testing of new birds, environmental testing

2. do not house budgerigars with other breeding parrots

3. avoid movement of bird before/during breeding season

4. vaccination of birds over 5-week-old, adults before breeding season (effectiveness controversial)

What is psittacid herpesvirus 1?

DNA virus with several genotypes and serotypes that causes both pacheco disease (peracute fatal disease) and mucosal papillomatosis

What are the clinical signs of pacheco disease?

1. highly contagious

2. sudden death most common (multiple birds)

3. sometimes preceded by depression, biliverdin-stained urates

How is pacheco disease diagnosed?

postmortem diagnosis of hepatic and splenic necrosis, PCR on tissues

How is pacheco disease treated?

acyclovir PO is efficient to reduce mortality, but birds will remain carriers after treatment

What birds are frequent subclinical carriers of pacheco disease?

Macaws, Amazon parrots, Patagonian and sun conures

What birds are most affected by mucosal papillomatosis?

Macaws and amazon parrots

What are the clinical signs of mucosal papillomatosis?

1. papillomas in oral cavity and cloaca

2. papillomas may wax and wane, disappear, or disseminate to GI tract

3. blood in droppings

4. papilloma prolapses through cloaca

5. upper GI signs (regurgitation, wasting disease) if dissemination

6. some birds develop bile duct and pancreatic duct carcinomas (signs of chronic liver disease)

How is mucosal papillomatosis diagnosed?

physical exam (oral cavity, eversion of cloacal mucosa) and PCR of cloacal/choanal swab

How is mucosal papillomatosis treated?

surgical removal of papillomas if necessary

What medication is unsuccessful in treating mucosal papillomatosis?

acyclovir (non-replicating form)

How is Psittacid herpesvirus 1 shed and spread?

shed in oral secretions and droppings, and birds are infected by ingestion of contaminated material

What can happen with birds that have lifelong Psittacid herpesvirus 1 infections?

potential sources for future outbreaks if housed with other parrots that have not been exposed to the virus

How can Psittacid herpesvirus 1 be prevented?

1. avoid introducing South-American parrots into mixed aviaries

2. meticulous physical examination and testing before entry

3. repeated testing by PCR (detects all serotypes) oral and cloacal swab, blood

4. vaccination

5. biosecurity

Which virus causes progressive feather dystrophy, abnormal beak and nails, as well as loss of powder down in cockatoos?

Circovirus

2 multiple choice options

How are birds infected with poxvirus?

skin injury

How is poxvirus transmitted in birds?

mosquito bites, fomites, bites from other birds, etc...

What are the different forms of poxvirus in birds?

1. dry-pox

2. wet/mucosal pox

3. systemic pox

What is dry-pox?

raised lesions on face (eyelids, mouth commissure), feet, under wings. Normally self-limiting (lesions regress in a few weeks)

What is the mortality of dry-pox?

low

What is wet/mucosal pox?

blepharitis, conjunctivitis, diphtheritic lesions of the oral cavity and trachea

What is the mortality of wet/mucosal pox?

high in canary aviaries

What is systemic pox?

acute onset of depression, anorexia, dyspnea, peracute death, air sacculitis and pneumonia

How is poxvirus diagnosed?

clinical signs +/- histopathology

How is poxvirus treated?

supportive treatment

How is poxvirus prevented?

1. modified live vaccine for canaries and pigeons

2. hygiene and biosecurity, vector control

What is Orthoavulavirus 1?

RNA virus with different strains that vary in virulence that causes exotic newcastle disease and pigeone paramyxovirus-1

What is exotic newcastle disease?

1. highly virulent

2. has entered the USA on several occasions in smuggled parrots (amazons)

3. strict laws governing the movement of birds (quarantine, etc.) to protect poultry

4. depression, anorexia, respiratory signs, GI signs, CNS sign (ataxia, torticollis...)

What is pigeon paramyxovirus-1?

1. endemic in feral pigeon/dove populations, problematic for racing pigeon flocks

2. CNS signs (trembling, ataxia, paralysis..), diarrhea, polyuria

3. several birds affected in the flock, mortality

4. vaccinate pigeons >6 weeks prior to racing season

How is orthoavulavirus 1 diagnosed?

RT-PCR, virus isolation

What should you do if you suspect an Orthoavulavirus 1, Avian influenza (AI), or West Nile Virus (WNV) infection?

contact official veterinarian immediately

What are the important notifiable diseases mentioned?

1. Orthoavulavirus 1

2. Avian influenza (AI)

3. West Nile Virus (WNV)

What are the temporary regulations put in place during Avian influenza (AI) outbreaks?

1. requirements to house birds inside

2. closure of walk-through aviaries in zoos

3. submission of wild bird carcasses to state veterinarians

What must zoos have in relation to AI?

contingency plans for outbreaks

What is West Nile Virus?

mosquito-born flavivirus that causes fatal encephalitis in humans, horses, susceptible birds

What are the clinical signs of West Nile Virus?

1. unspecific signs

2. CNS signs

3. sudden death

What are birds in relation to West Nile Virus?

reservoirs that spread the virus (many are asymptomatic, but some are susceptible to disease)

How is West Nile Virus spread?

mosquito bites and eating infected birds

How is West Nile Virus diagnosed?

PCR on tissues/oral swabs, virus isolation, serology

How is West Nile Virus prevented?

avoid exposure to mosquitoes

What notifiable diseases share mosquito-borne transmission cycles with birds as amplifying hosts, but differ in geographic distribution, host susceptibility, and disease severity?

arboviral encephalitis such as West Nile Virus (WNV), Eastern Equine Encephalitis (EEE), and Western Equine Encephalitis (WEE)