Domestic poultry and birds are affected by coccidia called Eimeria. Different species of Eimeria that effect poultry are host-specific – meaning that a species that infects chickens does not infect turkeys and vice versa.
Nine species of Eimeria infect chickens. The species important in broiler production include Eimeria tenella (90%), E. maxima, E. acervulina, and E. mivati; the species important in breeder and egg- layers are E. burnetti and E. necatrix. Seven species infect turkeys – the big three of concern are Eimeria meleagrimitis, E. adenoeides, and E. gallapovonis.
- Direct life cycle
- 1 week prepatent period
- After oocysts are ingested, sporozoites are released which penetrate the intestinal epithelium
- 2 asexual phases of multiplication called schizogony occur followed by a phase of sexual multiplication called gametogony
- Zygote develops into an oocyst which is then shed in the faeces
- Oocyst measures 20-30μm
- For each oocyst ingested, thousands are shed
- Life cycle is self-limiting
- Organisms from a single infection go through the sequence of developmental stages synchronously
- Organisms leave the body simultaneously as oocysts
- Oocysts are only infective once they have sporulated
- Sporulation requires warmth, moisture and oxygen
- Takes 2-3 days in broiler houses
- Oocysts contain 4 sporocysts each with 2 sporozoites