Poultry Diseases affecting the Nervous System

Small and Backyard Flocks June 12, 2013 Print Friendly and PDF

There are many diseases that can affect the nervous system. Note that some diseases that affect the nervous system can also affect the respiratory system.

Viral Infections

Avian Influenza

Clinical signs of infection by avian influenza include the following:

  • Coughing 
  • Sneezing 
  • Rales 
  • Swelling of the face and/or wattles
  • Bluish-purple discoloration of face
  • General diarrhea
  • Red and/or white spots on the legs and comb 
  • Conjunctivitis (inflammation of the conjunctiva of the eye)

Marek's Disease

Clinical signs of Marek's disease include the following:

  • Unilateral paralysis of the wing or leg
  • Lameness 
  • Unthriftiness
  • Gray eyes and blindness

Newcastle Disease

Clinical signs of Newcastle disease include the following:

  • Coughing
  • Sneezing
  • Shaking head 
  • Rales
  • Gasping
  • Discharge from the eyes 
  • Discharge from the nose
  • Swelling of the face and/or wattles
  • Bluish-purple discoloration of the face 
  • Retarded growth
  • General diarrhea or green, watery diarrhea
  • Twisting of the head and neck (torticollis)
  • Conjunctivitis (inflammation of the conjunctiva of the eye)
  • Prostration

Eastern Equine Encephalitis

Eastern equine encephalitis affects gamebirds. Clinical signs of this disease include the following:

  • Unthriftiness
  • Leg paralysis
  • Twisting of the head
  • Tremors

Emus infected with this disease typically experience bloody diarrhea and death.

Bacterial Infections


Clinical signs of botulism include the following:

  • Inability to control the head
  • Sleepy demeanor 
  • Diarrhea

Fowl Cholera

Clinical signs of fowl cholera include the following:

  • Darkened head
  • Swollen head and wattles
  • Paralysis
  • Reduced egg production

Fungal Infections


Clinical signs of aspergillosis include the following:

  • Respiratory distress
  • Silent gasping or gurgling sounds
  • Death

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This work is supported by the USDA National Institute of Food and Agriculture, New Technologies for Ag Extension project.