An Update On Protozoan Parasites Of Poultry

Protozoa means first animals and it is identified as simple unicellular animals. The cells constitutes their bodies are eukaryotic and having endoplasmic reticulum, golgi apparatus, mitochondria and distinct nucleus in the cytoplasm. It has two form of nucleus such as compact and vesicular. Locomotion of protozoa is done by gliding or pseudopodia or flagella or cilia. Generally protozoa are found in, tissue, urogenital tract, intestinal tract and blood. Antoni van Leeuwenhoek was first person who invented the protozoan parasite and Eimeria stiedae was considered as first parasitic protozoan.The coccidia species are much more host specific it means species of coccidia found in ruminants they do not affect the poultry birds and vice versa.

Various protozoan parasites found in poultry of parasiteSite
iHistomonas meleagridisCaeca and liver
iiTetratrichomonas gallinarumLower digestive tract
iiiEimeria tenellaCeacum
ivE. necatrixJejunum, mid gut, caecum
vE. brunettiRectum
viE. acervulinaSmall intestine
viiE. mitisAnterior of half of small intestine (S.I.)
viiiE. maximaMiddle of small intestine
ixE. haganiAnterior of  part S.I.
xE. mivatiSmall intestine
xiE. praecoxUpper third of S.I.
xiiPlasmodium gallinaceumRed blood cell
xiiiAegyptianella pullorumRed blood cell

Histomonas meleagridis:

  • Also known as infectious enteropathy or black had diease.
  • The organisms are pleomorphic and it is depend upon stage of organism, location and stage of disease.
  • Poultry are reservoir hosts for turkeys so that do not raise turkeys with poultry.
  • Transmission is done through ingestion of eggs of Heterakis gallinarum containing Histomonas meleagridis.
  • Earthworm transmit the infection


  • Sulphur yellow dropping is the suggestive of infection.

Prevention and control:

  • Provide good management and sanitation.
  • Avoid the mixing of poultry with turkey.
  • Sick birds isolated and treated at earliest.

Tetratrichomonas gallinarum:

  • Its distribution is cosmopolitan.
  • It produces lesion in liver resembles as histomonosis.
  • The lesions are irregular and raised above the surface of liver.

Eimeria oocysts:

The oocyst, contains a zygote is extruded from the host body and passed with faeces and excreted oocyst is called as unsporulated oocystwhich contains. Under optimum conditon, sporogony takes place outside the body to form a mature infective stage such as sporulated oocyst while, sporulation is done by using 2.5% K2 Cr2 O7in laboratory. The identification of sporulated oocysts are based on the size, presence/absence of micropyle and its cap, shape, form index, presence or absence of residual, colour, polar and stiede bodies and sporulation time ( hours to days).

Eimeria tenella:

  • It is most common and highly pathogenic species.
  • Responsible for heavy economic losses in poultry sector.
  • Primarly causative agent of caecal coccidiosis.
  • The oocysts are broadly ovoid in shape.

Eimeria necatrix:

  • It is a common species.
  • Sporozoite is comma shaped.
  • Primarly it causes intestinal coccidiosis.
  • The oocysts are broadly ovoid in shape.

Eimeria brunetti:

  • It occurs in the mucosa of caecum, rectum, cloaca and lower portion of small intestine.
  • It causes rectal coccidiosis in poultry.
  • The oocysts are broadly ovoid in shape.

Eimeia acervulina:

  • Most common species found in the poultry.
  • Occurs in the epithelial cells of small portion anteriorly mainly duodenum portion.
  • It causes intestinal coccidiosis.
  • The oocysts ovoid with smooth wall in shape.

Eimeria mitis:

  • It is mostly occurs in anterior half of small intestine.
  • Oocystic wall smooth surface and yellowish in tinge.
  • The oocyst sub spherical in shape.

Eimeria maxima:

  • It causes intestinal coccidiosis.
  • The oocyst ovoid and ellipsoidal in shape.
  • It causes intestinal coccidiosis.

Eimeria hagani:

  • The oocyst broadly ovoid in shape.
  • Species is not much more common.

Eimeria mivati:

  • It causes intestinal coccidiosis.
  • Occurs in epithelial cells of small intestine.
  • The developmental stage may be seen in duodenal loop.
  • The oocyst ellipsoidal in shape.

Eimeria praecox:

  • It is commonly found in poultry.


  • Diagnosis is depends upon various types of lesions and location.
  • By faecal examination.
  • History of flock.
  • On the basis of post mortem examination.
  • On the basis of clinical symptoms.


  • Various drugs used against the coccidiosis such as sulfadimidine, nitrofurans, amprolium, monensin, lasalocid, salinomycin, halofuginine, toltrazuril, diclazuril etc.

Prevention and control:

  • Provide sufficient protection against disease.
  • Development of acquired immunity by repeated exposure of small number of oocyts.
  • Provide ample quantity clean water.
  • Offered feed free from any pathogens.
  • Sick poultry segregate immediately
  • Avoid the mixing of sick and healthy birds.
  • Provide proper space and good hygiene.
  • Sanitation practices should be followed strictly.
  • Cage and floor should be kept clean and disinfected.
  • Use of anticoccidial drugs against outbreak of coccidosis.

Plasmodium gallinaceum:

  • Plasmodium commonly called as malarial parasite of birds and others.
  • The culex and aedes mosquito act as vector.
  • Chicks are more susceptible as compared to adults.
  • It causes high mortality (upto 80 per cent).

Sign and symptoms:

  • Progressive emaciation and anaemia are seen in affected birds.
  • Liver and spleen become enlarged.
  • In acute cases glomerulonephritis may be seen.
  • Paralysis may be seen.
  • Due to blockage of capillary cerebral stroke may be found.


  • Diagnosis is done on the basis of clinical sign.
  • Blood smear examination.
  • Post mortem examination is the confirmatory diagnosis.

Prevention and control:

  • Avoid the accumulation of water around the poultry houses.
  • If possible use mosquito net.
  • Destroy the breeding places.
  • Use of suitable insecticide spray.
  • Fumigation may also helpful to control the mosquito population.
  • Sick bird should be treated and isolated from healthy flock.

Aegyptianella pullorum:

  • The soft tick, Argas persicus act as vector and trophozoite stage is seen inside the RBC.
  • It causes aegyptianellosis in acute, su acute or chronic stage.


  • The affected birds shows, diarrhoea, fever, icterus and anorexia.
  • Enlarged liver and spleen, anaemia is shown by infected birds during post mortem examination.

Prevention and control:

  • Use of suitable acaricide compound.
  • Provide immunity booster to the bird.
  • Burn the surrounding pasture.
  • Fill the cracks and crevices in poultry houses.
  • Cleaning of shed time to time particularly before introduction of new batches.
  • Provide proper space and hygiene.

Alok Kumar Singh1 Pradeep Kumar2 Amit Singh3 and Sunil Kumar Dhayal4

1 Department of Veterinary Parasitology, College of Veterinary Science & A.H., Kuthuliya, Rewa
2 Department of Veterinary Parasitology, DUVASU, Mathura
3 Department of Veterinary Parasitology, COVSc & A.H., Kumarganj, Ayodhya
4 B.V.Sc & A.H., Student, College of Veterinary Science & A.H., Kuthuliya, Rewa