Veterinary advice should be sought from your local veterinarian before applying any treatment or vaccine. Not sure who to use? Look up veterinarians who specialize in poultry using our directory listing. Find me a Vet


Avian Amyloidosis

Amyloidosis refers to a variety of diseases that result in the deposition of insoluble proteins (amyloids) in internal organs. The presence of these amyloids cause damage or altered function of the organs as they accumulate over time.

In humans, amyloid deposits from different, misfolded protein precursors have been associated with Alzheimer's disease, type II diabetes mellitus, multiple myeloma, familiar amyloid polyneuropathy, senile systemic amyloidosis, and inflammation-associated amyloidosis. Inflammation-associated amyloidosis, also referred to as amyloid A (AA), acquired, secondary, or reactive amyloidosis occurs systemically in susceptible chickens when excessive amounts of serum AA (SAA) protein are produced, primarily by the liver, resulting from chronic inflammation. Pekin ducks and brown laying hens have both been used as important research models of AA amyloidosis due to their predisposition.

Outbreaks of fatal AA amyloidosis have been documented in flocks of growing chickens within 3 weeks of receiving multiple co-administered vaccines. Systemic amyloidosis outbreaks have occurred in layer flocks that received multiple vaccinations with oil-emulsified bacterins.

Clinical Signs

Leg and joint swelling
Unexplained weight loss
Muscular weakness
Sudden death


  • History
  • Clinical signs
  • Immunohistochemistry
  • Biopsy
  • Necropsy


Supportive care


  • Prevention of chronic inflammatory conditions such as bumblefoot, gout, arthritis, aspergillosis, etc.
  • Do not administer multiple vaccines in one setting to chickens.

Scientific References

Good Overviews

Risk Factors

  • History of chronic inflammation or trauma
  • Existing tumor
  • Overcrowding
  • Recently administered multiple vaccinations.