Emeria spp In Poultry

Eimeria spp I The Poultry Monster

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Eimeria spp

The Eimeria spp in poultry is causing coccidiosis and it is the main causal agent. Eimeria spp is the largest genus in the family containing well over 1000 named species, with a number of important species affecting domestic mammals and birds.

Species of Eimeria are capable of causing significant morbidity and mortality and are discussed in detail under their respective hosts. It is called the poultry monster due to it is causing liver disease in poultry after introducing into the intestine.

See also- Top 3 drugs for the Eimeria spp


Phylum- Apicomplexa


Order –Eucoccidiorida


Family- Eimeriidae

Genus- Eimeria

Species- Eimeria tenella

See also- Bloody Ddiarrhea and Treatement in poultry

General characteristics

  • Oocysts Emeria spp are unsporulated when passed in the feces and require a period of development before becoming infected.
  • It is an intracellular lifestyle and possession of an apical complex at some stage of their development.
  • Its trophozoites have no cilia or flagella.
  • Reproduction Of Eimeria spp involves both asexual (merogony or schizogony) and sexual (gametogenic) phases.
  • Following gametogenic, a zygote is formed which divides to produce spores (sporogony).
  • Most of the most undergo merogony in the intestinal cells of their hosts.
  • The life cycle is usually homogeneous (occurring within one host) and the majority of species are
    highly host‐specific

Generalized life Cycle

The life cycle of Eimeria is divided into three phases: sporulation, infection, and merogony (schizogony), and finally gametogony. the divination of the Eimeria spp life cycle explains part-by-part later.

See also- life cycle stage of Eimeria spp in poultry

1. Sporulation

The sporulation process starts under suitable conditions of oxygenation, high humidity, and optimal temperatures of around 27°C, the nucleus divides twice and the protoplasmic mass forms four conical bodies radiating from a central mass. In the process, unsporulated oocyst which contains a nucleated mass of protoplasm enclosed by a resistant wall is passed to the exterior in feces.

The Eimeria oocyst (ref-veterinary parasitology, 4th edition)

Each of these nucleated cones becomes rounded to form a sporoblast, while in some species the remaining protoplasm forms the oocyst residual body.


The time taken for these changes varies according to temperature, but under optimal conditions usually requires 2–4 days. The oocyst, now consisting of an outer wall enclosing sporocysts each containing sporozoites, is referred to as a sporulated oocyst and is the infective stage.

2. Infection and merogony

this stage called the asexual reproduction of the Eimeria spp. The host becomes infected by ingesting the sporulated oocyst. The sporocysts are then liberated either mechanically or by carbon dioxide, and the sporozoites, activated by trypsin and bile, leave the sporocyst.

The Life cycle of the emeria spp
The Life cycle of the eimeria spp (ref-veterinary parasitology, 4th edition)

 In most species, each sporozoite penetrates an epithelial cell, rounds up, and is then known as a trophozoite.


After a few days, each trophozoite has divided by multiple fission to form a meront (schizont), a structure consisting of a large number of elongated nucleated organisms known as merozoites.

When division is complete and the meront is mature, the host cell and the meront rupture, and the merozoites escape invading neighboring cells. Merogony may be repeated, the number of meront generations depending on the species.

3. Gametogony and oocyst formation

this stage called the sexual reproduction of the Eimeria spp. Merogony terminates when the merozoites give rise to male and female gametocytes. The factors responsible for this switch to gametogenic are not fully known. The gametogenic phase is being divided into two gametocytes.

a) Macrogametocytes

The macrogametocytes are female and remain unicellular, but increase in size to fill the parasitized cell. They may be distinguished from trophozoites or developing meronts by the fact that they have a single large nucleus.

b) Microgametocytes

The male microgametocytes each undergo repeated division to form a large number of flagellated uninucleate organisms, the microgametes. It is only during this brief phase that coccidia has organs of locomotion.

4. zygote formation and Release

The microgametes are freed by the rupture of the host cell, one penetrates a macrogamete, and the fusion of the microgamete and macrogamete nuclei then takes place. A cyst wall forms around the resulting zygote, now known as an oocyst, and no further development usually takes place until this unsporulated oocyst is liberated from the body in the feces.

Host and site of infection for poultry

Every species of Eimeria has a host-specific and precise site of infection. This why clinical symptoms are varying according to species to species in the host system. Clinicians and veterinarians are confusing in some instances to specify the specific of Eimeria genera. the treatment depends on according to infection in the host.

See also- Organic Treatment of the Eimeria spp in poultry


There are seven species of the Eimeria are associating with causing infection in poultry. According to the Eimeria infection, they are inducing infestation in different sites in the intestine in poultry.

the common species of emeria and their size
the common species of emeria and their size in chicken ( (ref-veterinary parasitology, 4th edition)

See also- the sites of infection of the Eimeria spp in chicken with Image


The common species of eimeria in turkey with different location in the intestine is given below-

Eimeria adenoides– Lower small intestine, caeca

Eimeria innocua – Small intestine

Eimeria meleagridis Caeca

Eimeria meleagrimitis – Duodenum
Eimeria subrotunda -Small intestine


The common species of eimeria in quail with different location in the intestine is given below-

Eimeria colini -(Colinus) Unknown

Eimeria coturnicus– (Cortunix) Unknown

Eimeria tsunodai– (Japanese) Caeca
Eimeria uzura – (Japanese) Unknown

Eimeria taldykurganica– (Japanese, Cortunix) Unknown

Guinea fowl

Guinea Fowl has a common species of eimeria in Guinea fowl with different location in the intestine is given below-

Eimeria caviae – Large intestine

Eimeria grenieri Small intestine


Goose also infected with some species of emeria in Goose with different location in the intestine is given below-

Eimeria truncata -Goose Kidney

Eimeria anseris -Small and large intestine


Eimeria spp also affected in other birds with different location in the intestine is given below-

Eimeria anatisDuck Small intestine
Eimeria columbae– Pigeon Unknown
Eimeria labbaena (syn. E. peifferi, E.columbarum)  Pigeon, dove (rock, collared)  Small intestine

Oocyst and size

According to veterinary parasitology, 4 th edition, Eimeria has numerous types of oocyst and has a specific measurement on the microscopic view. The illustration has been presenting the most common types of Eimeria in tablet form.

The chicken oocyst and size
The chicken oocyst and size

The turkey oocyst and size
The turkey oocyst and size

The quail oocyst and size
The quail oocyst and size

The goose oocyst and size
The goose oocyst and size

The guinea fowl oocyst and size
The guinea fowl oocyst and size

The pheasant oocyst and size
The pheasant oocyst and size

The pigeon oocyst and size
The pigeon oocyst and size


In a final word, the above discussion totally explains the entire genera of the Eimeria spp in a general overview. As it is a normal inhabitant of the intestine of the poultry, it can lie all types of birds in the world and causing coccidiosis in poultry.

See also- Coccidiosis in poultry and Treatment

Reference- Veterinary parasitology, 4th edition

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