Avian Diseases, Pt. 3 Flashcards
What birds are typically most susceptible to salmonellosis, mycoplasmosis, and trichomoniasis?
SALMONELLOSIS = songbirds
MYCOPLASMOSIS = house finch
TRICHOMONIASIS = doves, pigeons
What causes Salmonellosis? What species are most affected?
Salmonella enterica (S. typhimurium most common) - Gram negative rod
songbirds, Garden birds
What songbirds in North America are most affected by Salmonellosis?
- pine siskin
- common redpoll (Canada)
How is Salmonellosis transmitted? What makes more likely to be transmitted?
fecal-oral - winter/spring
bird feeders - clusters of birds + feces
Why is Salmonellosis presentation unique in songbirds?
not usual enteritis - upper GI signs in the esophagus and crop
What are the 3 most common clinical signs of Salmonellosis?
- birds are abnormally tame, weak flight, and stay on feeders
- found dead at feeders
- emaciation
Where are most gross findings found in songbirds with Salmonellosis? What 4 things are found?
esophagus and crop
- necrosis
- fibrinonecrotic pseudomembrane
- Gram - rods
- heterophilic to granulomatous inflammation
What 2 unique gross lesions are found in songbirds with Salmenollosis?
- foci of necrosis/inflammation in other organs/tissues, like the pectoral muscles, brain, and liver
- arthritis in waterfowl
Salmonellosis, GI:
- pectoral atrophy
- crop full of necrotic material
Salmonellosis, GI:
- esophagus/crop
- yellow, fibrinonectrotic plaques
Salmonellosis, crop:
full thickness
Salmonellosis, systemic:
pale nodules with G- rods and heterophils with granulomatous inflammation
How is Salmonellosis diagnosed?
- signalment, gross lesions, histopathology
- Gram negative rods on culture from crop and liver tissue
How is Salmonellosis controlled?
reduce contact and crowding around bird feeders
- messy feeders with seeds and feces on the ground
- platform feeders
Is Salmonellosis zoonotic?
yes, just not to humans
- feral cats feeding on siskins and redpolls
What causes Mycoplasmosis? What birds are most affected?
Mycoplasma gallisepticum - bacteria without a cell wall growing as a sunny-side-up egg colonies
house finches
What has caused the spread of Mycoplasmosis in North America?
house finches used to be a western species, but the 40’s Hollywood finch was brought to eastern NA, didn’t sell well as pets, and were released
- Washington, DC = first outbreak in 1993-1994
How has citizen science helped diagnose and track Mycoplasmosis?
Project FeederWatch - people submit what birds are seen dead at feeders
What is characteristically seen in finches affected by Mycoplasmosis?
dramatic keratoconjuncitivitis
How is Mycoplasmosis transmitted? What does the bacteria target?
direct contact with surfaces or droplets (ocular/sinusoidal secretions) without any vertical transmission in finches
ocular and nasal/sinusoidal mucosae and adheres to the apical surface of the epithelium
In what 2 ways does Mycoplasma gallisepticum cause damage? What inflammation results?
- inhibition of ciliary activity of the respiratory epithelium
- secretion of cytotoxic substances
lymphocyte and plasma cells - no cell wall or LPS so no heterophilic response
What are the 2 most common clinical signs in finches with Mycoplasmosis?
- swollen eyelids (conjunctivitis and blepharitis) - blindness, serous exudate
- emaciation and or predation leads to death
Mycoplasmosis, histopathology:
conjunctivitis, blepharitis, sinusitis - lymphoplasmacytic, focally extensive, subacute, marked to severe
- inflammatory cells trying to reach Mycoplasma in the surface epithelium
Mycoplasmosis, diganosis IHC:
How is Mycoplasmosis diagnosed? What is not recommended?
PCR, qPCR
culture - very difficult, too many other organisms
How is Mycoplasmosis controlled?
reduce contact/crowding at bird feeders, or using suet feeders rather than tube feeders
What causes Trichomoniasis?
Trichomonas gallinae - protozoan trophozoites with flagella and undulating membranes
- Trichomoniosis
- Canker (doves and pigeons)
- Frounce (raptors)
What species are most affected by Trichomoniasis?
doves and pigeons
- raptors that feed on them
- emerging in finches
When is Trichomoniasis most commonly found?
summer - based on nesting time and presence of offspring
In what 3 ways is Trichomoniasis transmitted?
- crop milk from parent to offspring
- contact with infected surfaces - feeders/water baths
- regurgitated material - finches feed on this from pigeons
What is the tissue tropism of Trichomoniasis? How does it replicate?
- oral cavity
- esophagus
- crop
- cranial bones
binary fission
What are the 3 most common clinical signs of Trichomoniasis?
- weakness, fluffed feathers, loss of predator response
- regurgitation and crusty material around beak
- emaciation
Trichomoniasis:
What gross finding is most commonly found in Trichomoniasis?
caseous material (cankers) in lumen of the esophagus, crop, or mouth + thickened esophageal or ingluvial wall
Trichomoniasis, cankers:
regurgitate because they can’t swallow past the canker
What is most commonly seen on histopathology in Trichomoniasis?
esophagitis/ingulvitis/stomatitis with occasional osteomyelitis and/or hepatic necrosis
Trichomoniasis, histopathology:
no special stains work - intralesional protozoans
Trichomoniasis, necrosis:
How is Trichomoniasis diagnosed? What is the best way to detect the Trichomonad?
signalment, season (Summer!), gross lesions, histopathology
- direct smear/culture in pouches
- PCR
What is the best way to control Trichomoniasis?
prevent overcrowding by eliminating feeders, or at least remove platform ones, since it increases the risk of consuming regurgitated material and contact with doves/pigeons
- finches have become carriers because they share feeders, which can help increase the virulence of new strains
