Coccidiosis is a disease that affects nearly all birds and animals, and is caused by coccidial protozoa. While nearly all animals are affected by coccidiosis, the disease is typically not spread from one species to another, with one well-known exception being toxoplasmosis, which is spread from cats to humans. Coccidiosis is one of the most widespread and common poultry diseases, and costs the poultry industry more than any other. Warm and wet conditions are ideal for outbreaks, which are most likely to affect growing birds, however mature birds can also contract the disease.
Who: All birds and animals.
Where: Very common worldwide. Spreads more quickly in the most favorable conditions: warm (70-90 degrees F) combined with adequate moisture/humidity.
When: Any age, but mostly young birds.
Why: Protozoa causing infection in the digestive tract.
How: Coccidiosis is not transmitted bird-to-bird. It is contracted by ingestion of sporulated oocysts from:
Treatment: Various antibiotics, but not all, are effective in treating coccidiosis. As always, follow label instructions carefully! According to the "Penn State Poultry Health Handbook, 4th Edn", Sulfadimethoxine is "now the drug of choice for treating outbreaks" (pg. 183). Additionally, the following link contains "Drugs for Treatment of Coccidiosis in Chickens". Follow the link and scroll past Table 1 to Table 2.
Vaccine: Commercial vaccines exist and are becoming more popular.
Affects: Digestive system, particularly the intestinal tract. Various types of Coccidia affect different portions of the intestines and/or cecum.
Clinical Diagnosis: Fecal testing; Definite diagnosis by necropsy through the presence of intestinal and cecal lesions and the presence of oocysts. Specific coccidial type, or species, is determined by the portion of the intestinal tract that is affected by lesions, as well as the type of oocysts present. A useful chart detailing the affects of different species of chicken coccidia is included in the "Penn State Poultry Health Handbook, 4th Edn" on page 187.
Diseases with similar symptoms: Blackhead, salmonellosis, worms
Duration of symptoms: Most surviving birds recover in 10-14 days.
Incubation: 1-2 days for oocysts to sporulate and become infective; 4-7 days from ingestion to the presence of observable symptoms
Morbidity: Usually High (>50%)
Mortality: Cecal Coccidiosis (acute) has high mortality rates - up to 100% in young birds. Intestinal coccidiosis (chronic) causes a much lower incidence of mortality. The severity of Coccidiosis depends largely on the number of infective oocysts which are ingested by the bird(s).
Transmission to people: Humans can be affected by coccidian protozoa, however they are not usually spread from one species to another; humans are not known to contract coccidiosis from birds.