Common Bacterial Diseases of Birds Flashcards
OBJ: Know common bacterial diseases of different groups of birds
OBJ: know how to diagnose and treat them
clinical signs
organ system affected
Recommended diagnostic tests
Recommended treatment protocols
OBJ: Identify which diseases are a zoonotic concern
What is the normal bacterial flora of companion birds?
- Lactobacillus
- Corynebacterium
- Nonhemolytic Streptococcus
- Micrococcus spp
- Staphylococcus epidermidis
What gram- positive bacterial pathogens do birds commonly get?
- Staphylococcus aureus
- Staphylococcus intermedius
- Clostridium
- Enterococcus
- Streptococcus
- Other Staphylococcus spp
- Mycoplasma
What Gram negative bacterial pathogens do birds get?
- Klebsiella
- Pseudomonas
- Aeromonas
- Enterobacter
- Proteus
- Citrobacter
- E. Coli
- Serratia marcescens
- Salmonella
What intracellular bacterial pathogens do birds get?
- Mycobacterium
- Chlamydia
Which bacterial species is most commonly isolated from pododermatitis lesions in birds
Staphylococcus aureus
What are the different species of Mycobacteria that birds get? What is their common characteristics? Zoonotic?
- All are Acid-fast positive organisms
-
M. avian-intracellulare complex
- M. avium avium
- LOW zoonotic potential
-
M. genavense
- LOW zoonotic potential
- MOST common in pet birds
-
M. tuberculosis & M. bovis
- typically reverse zoonosis (they get from humans)
What other bacteria stain acid fast positive? what color is a positive acid fast staining bacteria?
- Nocardia species
- Legionaella micdadei
- Stain RED
Which birds are susceptible to Avian Mycobaccteriosis? Transmission?
- ALL species susceptible
- immunocompromised individuals at greatest risk
- Transmission:
- primarily oral route
- possible aerosol route
What are the clinical signs of Avian Mycobacteriosis?
- Chronic weight loss
- Very thin body condition
- GI and hepatic signs
- Respiratory signs - less common
What lesions are seen with Avian Mycobacteriosis
- Most common in GI tract and liver
- Lungs - can see extensive involvement of respiratory system
- Masses in skin and conjunctiva
What is the Pathogenesis of Avian Mycobacteriosis?
- Oral inoculation
- Infects intestines (not lymph nodes)
- Spreads to liver, spleen, bone marrow, lungs, air sacs, gonads, other organs
- Formation of noncaseated nonmineralized nodules in different organs
- Birds present with chronic disease
- due to prolonged immunologic battle between host (CMI response) and pathogen
- Immune failure due to ability of mycobacteria to downregulate killing mechanism of macrophages
- prevents normal fusion of phagosomes and lysosomes
How is Avian Mycobacteriosis diagnosed?
- PCR of tissue biopsies
- Histopathology with acid fast stain
- Cytology:
- presence of “ghost organisms” (do not pick up stain)
- Culture:
- very slow growing
- M. genavense can take 6 months
What is the treatment for Avian Mycobacteriosis?
- Euthanasia often recommended due to zoonotic risk
- never documented
- very low risk, but still a risk to immunocompromised
- Advanced cases are usually euthanized
-
Triple or quadruple therapy
- isoniazid, clarithromycin, ethambutol, rifampin
- VERY LONG treatment
- consider quality of life
- Disease tends to recur years later
What external lesions are seen in Avian Mycobacteriosis?
- Poor BCS - thin, emaciated, atrophy of pectorals, prominent keel
- SC swellings that appear as tumors
- usually on head, face, occasionally mandible and neck
- Nodules in eyelids
- Pathologic fractures of long bones d/t osteomyelitis
What internal lesions are seen in Avian Mycobacteriosis?
- Pale yellow to tan nodules in 1+ organs
- Organs affected-
- liver, spleen, intestines, lungs, air sac, thoracic and abdominal cavities
- Organs affected-
- Severe intestinal thickening “rope like”
- Amyloidosis has be linked to some species (Anseriformes)
- Affects liver, spleen, intestine, adrenal gland
- diffuse enlargement, yellow, waxy appearance
- Affects liver, spleen, intestine, adrenal gland
What histopathology is common in cases of Avian Mycobacteriosis?
- Granulomas - caseous; central area of necrosis with accumulation of eosinophilic debris, surrounded by layer of multinucleated giant cells
- common in: gallinaceous birds (chickens, turkey, quail) pigeons, ratites, raptors
- Lepromatous reaction
- Infiltration of a large number of foamy macrophages +/- multinucleated giant cells but NO tissue necrosis
- common lesion in psittacines and passerines
- Additional infiltrates of lymphocytes on the periphery
- NOT common in psittacines
- Infiltration of a large number of foamy macrophages +/- multinucleated giant cells but NO tissue necrosis
What birds are commonly affected by Mycoplasmosis?
- Passerines
- epizootic in house finches and gold finches - inusitis
- Agent: M. gallisepticum
- Poultry
How is Mycoplasmosis transitted to other species?
- Mycoplasma is a commensal organism is other species (especially raptors)
- Highly transmissible - spread through ocular and nasal discharge
- Poor survival outside hose
- Requires exchange of discharges
- Sites of close contact - bird feeders, roosting sites
What are the clinical signs of Mycoplasmosis?
- Conjunctivitis
- red, swollen eyelids and conjunctival tissue
- Clear ocular surface
- Rhinitis and sinusistis
