Eimeria vaccines for poultry are mainly composed of live oocysts. Concerns about the safety of coccidiosis vaccines have been raised by field users. This study compares the safety parameters of commercial non-attenuated and attenuated Eimeria vaccines with EVALON®, a live attenuated coccidiosis vaccine for breeders and layers.
Most of the Eimeria vaccines available for chickens consist of live parasites that need to undergo two and sometimes three entire life cycles inside the host gut in order to trigger the immune system and subsequently establish a full protective immunity.
On the market, there are live non-attenuated and attenuated vaccines. Live non-attenuated vaccines consist of parasites that still maintain their natural virulence.