Internal Parasitic Diseases

• Diarrhea can indicate an internal parasitic disease such as the presence of ascarids, large intestinal roundworms.
  
  

Respiratory Diseases

• Diarrhea can indicate respiratory diseases such as Newcastle disease, avian influenza, infectious coryza, laryngotracheitis and mycoplasma gallisepticum.
  
  

Nonrespiratory Viral Diseases

• Diarrhea can be a sign of nonrespiratory viral diseases such as Marek's disease, lymphoid leukosis, equine encephalitis and egg drop syndrome.
  
  

Nonrespiratory Bacterial Diseases

• Diarrhea can be a symptom of nonrespiratory bacterial diseases such as fowl cholera, pullorum, necrotic enteritis and staphylococcus.
  
  

Protozoan Diseases

• Some protozoan diseases, such as coccidiosis and blackhead, cause diarrhea.