Avian Coccidiosis: Diagnosis & Treatment Protocols
A detailed clinical reference covering Eimeria life cycles, lesions, and Amprolium dosages.
Scientific Overview
Avian coccidiosis is a highly infectious parasitic disease of the intestinal tract in poultry, caused by protozoan parasites of the genus Eimeria. It is a major cause of economic loss in broilers and layers, resulting in poor weight gain, elevated feed conversion ratio (FCR), and mortality.
Pathology and Clinical Symptoms
The pathognomonic symptoms of coccidiosis in chickens include ruffled feathers, severe depression, loss of appetite, pale comb/wattles, and bloody droppings or orange mucoid diarrhea. Gross pathological lesions are species-specific: Eimeria tenella causes severe mucosal thickening and bleeding in the ceca; E. acervulina causes transverse white plaques in the duodenum; E. necatrix causes severe mid-gut ballooning and congestion.
Veterinary Treatment & Control
Clinical outbreaks require immediate therapeutic administration of Amprolium (0.012% to 0.024% in drinking water for 3 to 5 days) or Toltrazuril. Use our vaccine diluter tool to calculate dosing volumes. Prevention relies on live vaccines sprayed at hatch, or coccidiostats mixed in starter feed feeds.
All scientific data, diagnostic criteria, and performance benchmarks presented on this page are derived from published peer-reviewed journals and official veterinary codes:
- Avian Pathology & Diagnostics: World Organisation for Animal Health (WOAH, 2023). Manual of Diagnostic Tests and Vaccines for Terrestrial Animals. Paris, France.
- Poultry Diseases & Histology: Swayne, D.E., et al. (2020). Diseases of Poultry (14th ed.). Wiley-Blackwell / American Association of Avian Pathologists.
- Nutrition & Feed Chemistry: Leeson, S. & Summers, J.D. (2001). Commercial Poultry Nutrition (3rd ed.). University Books, Guelph, Ontario.
- Commercial Breed Standards: Aviagen (2024). Ross 308 & Cobb 500 Broiler Performance Objectives. / Lohmann Breeders (2024). Lohmann Brown Management Guide.