Coccidiosis

Coccidiosis is an intestinal disease affecting poultry flocks around the world. It is caused by the protozoan parasite Eimeria. Birds contract the parasites by ingesting them in the droppings of infected birds.

Coccidiosis results in intestinal lesions, impaired growth, poor feed utilization, poor flock uniformity and increased mortality. Because it damages the intestinal lining, coccidiosis predisposes birds to the development of necrotic enteritis, another intestinal disease caused by the bacterium Clostridium perfringens.

For years, the primary method for controlling coccidiosis, especially in broilers, has been in-feed anticoccidials. With their prolonged use, however, Eimeria organisms have become resistant to anticoccidials, hindering coccidial control. In addition, consumer demand for poultry raised without antibiotics has increased.

These trends have prompted more producers to use vaccination to control coccidiosis. With vaccination, a controlled, balanced dose of Eimeria antigens are administered once to day-old chicks, initiating the development of natural, lifetime immunity against Eimeria.

Vaccination eliminates the need for withdrawal times, which are required when anticoccidials are used in the feed, as well as concerns about possible drug residues in poultry meat. Vaccination is also used to restore sensitivity to anticoccidials by replacing resistant, in-house, wild strains of Eimeria with drug-sensitive Eimeria strains.