Avian Infectious Diseases Flashcards
What can make spread of zoonotic avian diseases more wide-spread?
migration and flight of wild birds
- infectious disease has been the cause of extinction!
What avian species typically are affected by Polyomavirus infection? Which are most at risk? How is it transmitted?
all psittacines
nestling age Budgies and Parakeets, especially those that are hand raised
inhalation from droppings and feather/skin dander - common in multi-bird facilities
When does infection of Polyomavirus occur in Buderigars? What 5 clinical signs are associated? How long do they shed?
within a few days of hatching (10-20 days)
- ascites
- crop stasis
- acute death
- feather abscence/malformation
- survivors are often stunted with malformed/missing feathers (French molt)
until at least 6 m/o
When does infection of Polyomavirus occur in other psittacines? What 5 clinical signs are associated? How long do they shed?
at feathering (4-6 weeks) - all ages susceptible, adults tend to be asymptomatic
- acute death
- swollen coelom due to hepatomegaly
- depression, weight loss
- crop stasis
- bruising, hemorrhage
several weeks, small percent can shed for life
Polyomavirus:
BUDGIES - stunted growth with feather loss = French molt
- L is 6 months old and should be fully feathered by now
What antemortem and postmortem diagnostics are available for Polyomavirus infection?
ANTEMORTEM - PCR using DNA from cloacal swabs, blood, feather dander, or tissue samples; histopath with basophilic IN and IC inclusions
POSTMORTEM - pale muscles, SQ and cardiac ecchymoses, pale/enlarged liver
How is Polyomavirus infection treated? Prevented?
supportive care - poor prognosis
- maximize nursery husbandry - only keep hatchlings from same source together, stop breeding 6 mo to 1 yr and move adults to disinfect
- commercial vaccine
What does psittacine herpesvirus-1 infection cause? What species are most commonly affected? How is it transmitted?
Pacheco’s disease - high morbidity and mortality with asymptomatic carriers for life
all psittacines, most commonly New World - Macaws, Parrots
feces and respiratory secretions - 5-14 day incubation
What 3 clinical signs are associated with PsHV-1 infection? What antemortem diagnostics are used?
Pacheco’s disease:
- acute death
- severe hepatitis = biliverdinuria and yellow regurgitation/diarrhea
- papillomatosis in survivors
increased AST, leukopenia, PCR on blood, choana, cloaca
What are 4 postmortem lesions seen with PsHV-1 infection? What is seen on histopathology?
- hepatosplenomegaly
- renomegaly
- hepatic necrosis
- pericardial hemorrhage
eosinophilic IN inclusion bodies
What treatment is recommended for PsHV-1 infection?
- supportive care
- Acyclovir
(poor prognosis)
What is a common development with PsHV-1 infection in survivors and asymptomatic carriers? What is associated? What clinical signs are seen?
papillomatosis of oral mucosa, cloaca, or GIT
bile duct carcinoma and pancreatic duct carcinoma (internal papillomatosis)
- hematochezia
- tenesmus
- dyspnea/wheezing
- ptyalism
How are PsHV-1 papillomas treated?
- analgesia
- cautery or surgical excision
- antibiotics if ulcerated
recurrence is common!
What causes Psittacine Beak and Feather Disease (PBFD)? What psittacines are most commonly affected? How is it transmitted?
Circovirus
juveniles - especially cockatoos
feces, feathers, fomites, crop secretions - 3 weeks to several years of incubation
What signs are associated with PBFD?
- progressive feather loss (infects feather pulp) with delayed molt
- hyperkeratosis of feather sheath
- beak necrosis common in cockatoos
- immunosuppression = secondary infection
What diagnosis is preferred for PBFD?
- PCR on blood, feces, and feathers
- include healthy individuals —> if +, isolate and retest in 3 months
What treatment is recommended for PBFD? How is spread prevented?
supportive care —> poor prognosis
- isolate/euthanize infected birds
- quarantine and screen new birds
- treat the environment
What causes Proventricular Dilatation Disease (PDD)? What species are most commonly affected? How is it transmitted?
Bronavirus
all psittacines - rarer in smaller parrots
fecal-oral
What is the pathogenesis of PDD? What does this result in?
infects autonomic nerve ganglia, resulting in paralysis and dilatation of the proventriculus
despite normal appetite, the infected bird will lose weight and body condition (previously known as Macaw wasting disease)
What 5 clinical signs are associated with PDD?
- lethargy
- weight loss
- regurgitation
- maldigestion = undigested feed in feces
- neurological signs
What 3 antemortem diagnostics are used for PDD? What is seen on necropsy?
- radiographs/fluoroscopy - enlarged proventriculus
- PCR of choana, cloaca, or feces - intermittent shedding, must have 3 negative tests for a true negative
- biopsy of crop/proventriculus - lymphoplasmacytic infiltration of autonomic nerve ganglia
enlarged proventriculus
PDD, radiographs:
- normal
- moderate outpouching to the left of the cardiohepatic silhouette
- severe dilatation of proventriculus with ventriculus displacement
What treatments are recommended for PDD? How is it prevented?
- easily digested food
- NSAIDs - Meloxicam, Celebrex
isolate positive birds and quarantine new birds for up to 6 months and screen
What are the primary hosts of WNV? What are 3 methods of transmission?
birds —> corvids, raptors, and ratites develop clinical signs
- mosquito vectors
- close contact
- feces and saliva
What signs are associated with WNV infection in birds?How is it diagnosed?
neuro signs and sudden death
Western blot
What treatment is recommended for WNV? How is it prevented?
supportive care
- vaccinate susceptible birds with equine vaccine
- mosquito control
What transmits Poxvirus? What are the 3 forms of disease?
biting insects
- acute septicemic - very rare
- wet pox - diphtheroid oral cavity, trachea
- cutaneous/dry pox
What are 2 options for diagnosing Poxvirus infection? What treatment is recommended?
- impression smear - IC eosinophilic inclusion bodies
- histology
- typically self-limiting and resolves in 3-4 weeks
- supportive care
- systemic antibiotics
What is the normal microbial microflora of birds like? In what birds are bacterial infections most common?
G+ rods and G+ cocci; not all G- are bad, pair with history and clinical signs
young birds
What causes Chlamydophilosis in birds? What birds are most susceptible?
Chlamydophila psittaci
any aged parrot species (Cockatiels and Budgies tend to be asymptomatic) —> ZOONOTIC and REPORTABLE, causes flu-like symptoms in reptiles and other mammals
How is Chlamydophilosis transmitted? What is prognosis like?
direct - feces, nasal.ocular d/c, feather dust —> incubates 3 or more weeks within elementary bodies
good if caught early
What are the 2 most common signs of Chlamydophilosis? What else is seen? How do asymptomatic carriers present?
- conjunctivitis
- rhinitis - nasal d/c, sneezing
- depression, anorexia, weight loss
- biliverdineuria
- hepatic, renal, or GI involvement
develop clinical signs in times of stress
When should samples be taken in patients with suspected Chlamydophilosis? What are 4 options for diagnostics?
while showing signs —> subclinical = not shedding, difficult to diagnose
- PCR of feces or nasal/ocular d/c + serology on blood, choana/cloacal swab
- IFA or culture
- radiographs - splenomegaly, hepatomegaly
- bloodwork - leukocytosis, elevated liver enzymes
What postmortem diagnostics is used for Chlamydophilosis? How is it prevented?
histopath - hepatic necrosis and inflammation
- test repeatedly for boarding
- screen large aviaries with a pooled sample
- consider all birds sharing the airspace exposed!
How is Chlamydophilosis treated?
- prolonged Tetracycline for a minimum of 45 days
- disinfect environment with detergent, like bleach
- there is only short-lived immunity following infection, recurrence is common!
(REPORTABLE)
What causes Salmonellosis in birds? How is it transmitted?
Salmonella spp
fecal oral —> ZOONOTIC, commonly seen in immunocompromised and can be passed back to birds
What 4 clinical signs are associated with Salmonellosis in birds? How does subacute disease commonly present? What happens to survivors?
- anorexia, lethargy, dehydration
- diarrhea
- GI stasis
- dyspnea
CNS signs, dyspnea, renal/liver/spleen damage
carriers with clinical signs in the future with stress events
What antemortem and postmortem diagnostics are used for Salmonellosis?
ANTEMORTEM - fecal culture, requires 3 negatives to confirm
POSTMORTEM - muscle degeneration, splenomegaly, hepatomegaly, air sacculitis, nephropathy, gastroenteritis
What treatment is recommended for Salmonellosis?
- antibiotics
- disinfect environment
- cull carriers
- autogenous inactivated vaccine
What causes avian tuberculosis? What birds are most commonly infected? What clinical signs are associated?
Mycobacterium avium
immunocompromised (ZOONOTIC!)
- lethargy
- chronic wasting, poor feathering
- diarrhea
- abdominal distension
- SQ masses
- acute death
What are 4 options for diagnosing avian tuberculosis?
- acid fast stain of feces, aspirates of granulomas, or tissues
- PCR/DNA probes
- culture - requires special media
- bloodwork - severe leukocytosis
What treatment for avian tuberculosis is recommended?
- prolonged supportive therapy + isolate for years
- euthanasia
How does Aspergillus appear microscopically? How does it infect birds?
septate hyphae with dichotomous branching
ubiquitous in the environment and NOT contagious - depends on host immunity, agent, and environmental factors (hot, humid)
Where are Aspergillosis infections most common in birds? How is it transmitted? What is prognosis like?
lower respiratory tract —> hot and humid air sacs and airways (+ syrinx) —> may also cause nasal granulomas
inhalation —> causes infection with stress and illness
good with early recognition and treatment
What clinical signs are seen with Aspergillosis?
- dyspnea
- voice change with syrinx involvement —> may need air sac cannulation
- nasal granulomas common in Amazon parrots
- exercise intolerance
- anorexia, weight loss
- lethargy
- diarrhea
What are some options for diagnosing Aspergillosis? What is the most successful?
- history - overcrowding, poor diet, poor ventilation, chronic stress
- CBC - severe leukocytosis
- serum protein electrophoresis - increased GLOB
- cytology
- culture - extended time required for fungi
- PCR
- radiology - radiopaque air sacs/airways (increased pulmonary density
ENDOSCOPY - observes granulomas, can administer treatment or remove them
Aspergillosis, endoscopy:
What 4 treatments are recommended for Aspergillosis? What monitoring is done during treatment?
- surgical debridement of large lesions
- antifungals - Azoles, Terbinafine, Amphotericin B (PO, topical, nebulization)
- supportive care
- improve husbandry
serial radiographs/endoscopy + Galactomannan titers
What gastric yeast most commonly infects birds? What birds are most commonly affected? What does it cause?
Macrohabdus ornithogaster - likely opportunistic
Budgerigars - rare in large psittacines
- proventriculitis
- crop stasis
- distal GI lesions
What clinical signs are associated with avian gastric yeast infections? How is it diagnosed?
- weight loss
- anorexia with good appetite
- regurgitation - thick, mucoid, commonly caked on feathers
- maldigestion
- diarrhea
fecal smear with Lugol’s iodine or phase contrast microscopy +/- PCR
What treatment is recommended for avian gastric yeast infections?
- Amphotericin B (some resistance associated)
- Itraconazole
- supportive cafre
What causes Candidiasis in birds? What does it cause? What environments are infections most common?
Candida albicans - budding yeast +/- pseudohyphae ubiquitous in the environment, infection suggests immunosuppression
crop mycosis, thrush, sour crop
high humidity and temperature —> hand reared, weanlings in brooders, tropical environments
Other than immunosuppression, what causes Candidiasis?
- prolonged antibiotics use
- diets high in sugars and carbohydrates
What signs are indicative of Candidiasis?
- thickened crop = Turkish towel
- caseous plaques in oropharynx, crop, and esophagus
- weight loss with normal appetite
- crop stasis
- regurgitation
- loose feces with foul odor
What 3 diagnostics are used for Candidiasis?
- wet mount of Gram stain of lesions, crop wash, or feces
- culture
- histopath - epithelial hyperplasia
(difficult, considered a normal commensal organism)
What treatment is recommended for Candidiasis?
- Ketoconazole or Itraconazole
- Nystatin or Amphotericin B
- improve husbandry
What is the scaly leg mite? What birds are most commonly infected? How are they transmitted?
Knemidokoptes spp —> burrowing mite observed in featherless areas
Budgies or Passerines
direct
What sign is indicative of scaly leg mite infection? How is it diagnosed? What treatment is recommended?
- feather loss around beak and eyes
- SEVERE = hyperkeratosis of facial skin, beak, and legs
direct visualization or tape prep
Ivermectin + treat environment
What are the 2 most common GI parasites in birds?
- Giardia
- Sarcocystis
How is Giardia transmitted? What signs are commonly seen?
fecal oral
- weight loss
- failure to thrive
- diarrhea
- feather destructive behavior in Cockatiels and Budgies due to malabsorption and hypersensitivites
What 2 diagnostics are used for Giardia infections? What treatment is recommended?
- direct smear - flagellate protozoa
- ELISA
Metronidazole
How is Sarcocystis transmitted? What are the 4 clinical forms?
ingestion of infected insects or feces from opossums
- acute pulmonary disease
- neurologic disease
- muscular disease
- myocarditis
What 2 diagnostics are used for Sarcocystis? Treatment?
- antemortem muscle biopsy and IFA
- necropsy shows hemorrhagic lungs and parasite ID
Pyrimethamine + TMS, pest control (opossum = DH and defecate sporocysts)
