Coccidia - Poultry

Buff orpington - nabrown RVC

Sporulated Eimeria - Joaquim Castellà Veterinary Parasitology Universitat Autònoma de Barcelona

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