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


Other Names: Crypto

Cryptosporidiosis is the name of the disease caused by infection with protozoan parasites of the genus Cryptosporidium. It manifests as either a respiratory or gastrointestinal disease, depending on the site of infection.

There are many species of Cryptosporidium that infect a wide range of animal species, including humans. The following Cryptosporidium species have been reported to infect chickens:
  • Cryptosporidium baileyi: Infects the Bursa of Fabricius, conjunctiva, kidneys, respiratory tract, cloaca, or rectum. Found worldwide and in a wide range of bird species.
  • Cryptosporidium meleagridis: Infects the small and large intestines. Found in Columbiformes, Galliformes, Passeriformes, and Psittaciformes worldwide.
  • Cryptosporidium galli: Infects the proventriculus. Affects chickens in Asia, Europe, Oceania, and South America. Found in Bucerotiformes, Galliformes, Passeriformes, Psittaciformes, and Phoenicopteriformes.
  • Cryptosporidium andersoni: Affects chickens and other Galliformes in Europe.
  • Cryptosporidium parvum: Infects the small intestine or caecum. Found in Accipitriformes, Anseriformes, Charadriiformes, Galliformes, Passeriformes, and Psittaciformes in Asia, Europe, and the Americas.

How Chickens get Cryptosporidiosis

Chickens become infected by ingesting Cryptosporidium oocysts excreted in the feces and surrounding environment, from an infected host. The host doesn't need to be a chicken. Many other species of birds can be infected hosts. Oocysts are capable of surviving outside their host for long periods of time (often greater than 6 months duration) in cool, moist environments, especially water sources.

How Cryptosporidiosis is Diagnosed

Cryptosporidium is detected in the conjunctiva, sinus, trachea, lungs, kidneys, small and large intestine, cloaca, and bursa of Fabricius in chickens.

Clinical Signs

Weight loss
Ruffled feathers
Nasal and eye discharge
Swollen sinuses
Difficulty breathing
Extending neck
Reluctance to move
Increased respiratory sounds (rales)
Undigested food in droppings


  • History
  • Clinical Signs
  • Physical exam
  • Lab Tests


Supportive careIsolate the bird from the flock and place in a safe, comfortable, warm location (your own chicken "intensive care unit") with easy access to water and food. Limit stress. Call your veterinarian.
Paramomycin100 mg/kg administered orally every 12 hoursK Marx



  • Good sanitary practices
  • Place water sources higher up to help prevent feces from contaminating the water source.
  • Prevent birds flying overhead from contaminating water sources with their feces.
  • Prevent exposure to wild birds.

Scientific References


Risk Factors

  • Keeping birds in a dirty, unsanitary environment.
  • Ingestion of untreated or fecal contaminated drinking water.
  • Wild or pet exotic birds on the premises.