Coccidiosis in Poultry | Symptoms, and Treatments

Coccidiosis in Poultry

Coccidiosis in Poultry is a very common health issue that needs to be treated to avoid any deadly consequences. If Coccidiosis is left untreated, then it can lead to mortality of poultry birds.

If you are new to the poultry sector, or not hear the word Coccidiosis ever before, then this is the right place for you; because in this article, we are going to cover every single detail about Coccidiosis in Poultry. So, stay tuned with us.

What is Coccidiosis in Poultry

Coccidiosis in Poultry is an intestinal disease that is caused by a protozoan ( coccidia ) that attaches itself to the intestinal lining and thus damages the wall of the gut leading to bleeding that can be seen in the droppings of birds. This protozoan prevents the absorption of feed ingredients from feed and creates such an environment in the gut that harbors a large number of bacteria.

What is the Cause of Coccidiosis in Poultry

Coccidiosis in Poultry is caused by a protozoan named coccidia. This parasitic protozoan belongs to the phylum Apicomplexan, the family Eimeriidae. Most species belong to the genus Eimeria. Coccidia spreads through infected bird’s droppings.

Cause of Coccidiosis in Poultry

Life Cycle of Coccidia:

For a better understanding of Coccidiosis in Poultry, you should have to know about the Life Cycle of Coccidia. The life cycle of Coccidia starts with a microscopic egg (oocyst). 

Stage -1 Shedding of Unsporulated Oocysts by Infective Birds

The infected birds shed the unsporulated oocysts in their droppings. These oocysts are not infective because they are unsporulated. These unsporulated oocysts can survive for at least one year if the conditions will be favorable for them. They can tolerate harsh environments because of their tough-resistant outer wall.

Stage -2 Conversion of Unsporulated Oocysts to Sporulates Cysts

Oocysts do not survive well at temperatures below -30°C or above 40°C; within this temperature range, oocysts may survive ≥ 1 yr. The unsporulated oocyst is then converted into sporulated oocyst under suitable conditions like when temperature, humidity, and oxygen are favorable. The temperature requirement for the conversion of unsporulated oocyst to sporulated is 21-32° C.

Stage -3 Formation of Sporozoites withinh Sporocysts of Oocyst

Sporulation generally occurs in moist, humid conditions. Areas around feeders and waterers are the prime location for these parasites, especially if these areas are not cleaned and maintained well. During sporulation, the amorphous protoplasm develops into small bodies (sporozoites) within secondary cysts (sporocysts) in the oocyst.

In Eimeria spp, the sporulated oocyst has four sporocysts, each containing two sporozoites; in Isospora spp, the sporulated oocyst has two sporocysts, each containing four sporozoites.

Stage -4 Sporozoited into Merozoites within Intestinal Epithelium

When the sporulated oocyst is ingested by a susceptible animal, the sporozoites escape from the oocyst, invade the intestinal mucosa or epithelial cells in other locations, and develop intracellularly into multinucleate schizonts (also called meronts). Each nucleus develops into an infective body called a merozoite; merozoites enter new cells and repeat the process.

Stage -5 Formation of Gametes for Next Generation

 After a variable number of asexual generations, merozoites develop into either macrogametocytes (females) or microgametocytes (males). These produce a single macrogamete or many microgametes in a host cell. After being fertilized by a microgamete, the macrogamete develops into an oocyst. The oocysts have resistant walls and are discharged unsporulated in the feces.

Life Cycle of Coccidia

Symptoms of Coccidiosis in Poultry

The most common Symptoms of Coccidiosis in Poultry are blood and mucus in the droppings of birds but keep in mind that sometimes birds shed dropping in red or dark brown color so don’t get confused with that. The best way to confirm that either this type of dropping is a sign of cocci or not is Vet examination, and then your vet will do a dropping analysis.

Also note, blood in poop is not necessarily always a symptom, so also look out the other Symptoms of Coccidiosis in Poultry:

  • Lethargic chickens with not easy to move around
  • Plae color comb and skin also appears yellowish
  • loss of appetite
  • Ruffled feathers
  • The declining growth rate in baby chicks
  • Weight loss
  • Decrease egg production or stops at all
  • Diarrheal droppings

All these symptoms could be a result of other diseases, so the only way to know for sure that you’re dealing with coccidiosis is to talk to your vet.

Symptoms of Coccidiosis in Poultry

Postmortem Findings of Coccidiosis in Poultry

The most common postmortem findings in Coccidiosis in Poultry birds are lesions throughout the intestine of birds. Why these lesions are present? This is because of the destruction of the intestinal epithelium. This may be accompanied by hemorrhage into the lumen of the intestine, catarrhal inflammation, and diarrhea. There are various types of poultry birds so we are going to discuss one by one.

Coccidiosis in Poultry Chickens:

In Chicken birds, coccidiosis is caused by a large number of Eimeriidae species. we will sum up according to the location of eimeriidae species.

1- Eimeriidae tenella:

If lesions are present only in cecum area of chickens then this an indication, that this coccidiosis is caused by Eimeriidae tenella. E tenella can be confirmed by the presence of bloody discharge and by cecum cores ( cecum cores are the clotted blood tissue debris, and oocysts around cloaca ).

2- Eimeriidae necatrix:

This species is responsible for causing coccidiosis in the small intestine and also cecum of chickens. When we see such types of coccidiosis lesions under a microscope then we see small white spots with bright or dull red lesions on the serosal surface.  This appearance is sometimes described as “salt and pepper.

3- Eimeriidae acervulina:

The lesions which are caused by this eimeriidae are present in Duodenal loop and upper small intestine. Most cases of Coccidiosis in Poultry are because of this species. The lesions are whitish, oval, or transverse patches in appearance.

4- Eimeriidae brunette

In such coccidiosis, the lesions are found in the lower small intestine, rectum, ceca, and cloaca. Under mild infections, the mucosa is pale and disrupted but lacking in discrete foci, and may be thickened. In severe infections, coagulative necrosis and sloughing of the mucosa occur throughout most of the small intestine.

5- Emeriidae maxima

Coccidial lessions develop in the small intestine, where it causes dilatation and thickening of the wall; petechial hemorrhage; and a reddish, orange, or pink viscous mucous exudate and fluid.

6- Eimeriidae mitis

The location of this parasite is in the lower small intestine. Lesions resemble with moderate infections of E brunette. E mitis can be distinguished from E brunetti by finding small, round oocysts associated with the lesion.

7- Eimeriidae praecox

It infects the upper small intestine, does not cause distinct lesions but may decrease the rate of growth. The oocysts are larger than those of E acervulina and are numerous in affected areas. The intestinal contents may be watery. 

E praecox is considered to be of less economic importance in causing Coccidiosis in Poultry than the other species.

Coccidiosis in Turkeys:

There are total seven coccidial species that are responsible for causing Coccidiosis in Turkeys. Out of them only 4 are pathogenic. Those four pathogenic species that are mainly causative agents for Coccidiosis in Turkeys are areE adenoidesE dispersaE gallopavonis, and E meleagrimitis.  The non-pathogenic are E innocuaE meleagridis, and E subrotunda.

1- Eimeriidae adenoeides and Eimeriidae gallopavonis

These infect the lower ileum, ceca, and rectum. These species often cause mortality. The developmental stages are found in the epithelial cells of the villi and crypts. The affected portion of the intestine may be dilated and have a thickened wall. Thick, creamy material or caseous casts in the gut or excreta may contain enormous numbers of oocysts.

2- Eimeriidae meleagrimitis

The upper and mid-small intestine are the site of infections for Eimeriidae melegrimitis. The lamina propria or deeper tissues may be parasitized, which may result in necrotic enteritis

Coccidiosis in Game Birds:

Whenever you hear the Coccidiosis in Poultry, it doesn’t means, only Chickens are susceptible to this problem. Infact 50% flock of game birds lose because of coccidiosis. The Chinese ringneck pheasant, the chukar partridge, and the bobwhite quail, extremely popular as game birds.

In pheasants, the common species are E phasianiE colchiciE duodenalisE tetartooimia, and E Pacifica.

Chukars are infected by two species: E kofoidi and E legionensis.

Bobwhite quail are infected mainly by E lettyaeE dispersa, and E coloni.

Treatment and control of Coccidiosis in Game Birds are similar to that in poultry; however, amprolium is not the first choice of drug in the Treatment of Coccidiosis in Game Birds. Monensin and salinomycin are the approved drugs for quail, and lasalocid and sulfadimethoxine/ormetoprim are the approved drugs for chukars.

Postmortem Findings of Coccidiosis in Poultry

How to Diagnose Coccidiosis in Poultry

There are two ways to diagnose Coccidiosis in Poultry. Either you can examine a live bird or a dead one. It is common sense that for a dead bird, you have to examine the lesions macroscopically and then microscopically to confirm the coccidiosis.

As lesions are a concern, I have already discussed in detail that lesions are present in different parts, and it depends on the causative agent. So, if you are going to inspect the lesions for Coccidiois then you have to see the location of lesions, type of lesions, and its anatomical appearance for a thorough diagnosis of Coccidiosis in Poultry.

For live poultry birds, the best way to diagnose Coccidiosis are signs and symptoms like weight loss, loss of appetite, pale comb, diarrhea, blood in droppings.

To confirm the diagnosis of Coccidiosis in Poultry, the Vet has to take a fecal examination test to assure the presence of unsporulated oocysts.

How to Diagnose Coccidiois in Poultry

Treatment of Coccidiosis in Poultry

Treatment of Coccidiosis in poultry is always a point of debate. Researchers in Veterinary sciences are continuously trying on the prevention and treatment methods of Coccidiois. Anticoccidial drugs are used in feed to prevent disease and the huge economic loss due to this issue.

The Vet doctors recommend the prophylactic use of anticoccidial drugs because most of the damage occurs before signs become apparent and because drugs cannot completely stop an outbreak.

Therapeutic treatments are usually given by water because of the logistical restraints of feed administration. Antibiotics and increased levels of vitamins A and K are sometimes used in the ration to improve rate of recovery and prevent secondary infections.

Problems that Arise During the Treatment of Coccidiois in Poultry:

The Problems that arise during the treatment of Coccidiosis in Poultry are

  • Develop of Resistance by Coccidial Strain
  • Coccidiostatic effect of drug
  • Coccidiocidal effect of anticoccidial drug

Develop of Resistance by Coccidial Strain:

Continuous use of anticoccidial drugs promotes the emergence of drug-resistant strains of coccidia. Various programs are used in attempts to slow or stop selection of resistance. For instance, producers may use one anticoccidial continuously through succeeding flocks, change to alternative anticoccidials every 4–6 month.

Coccidiocidal or Coccidiostatic effect of anticoccidial drug:

The effects of anticoccidial drugs may be coccidiostatic, in which growth of intracellular coccidia is arrested but development may continue after drug withdrawal, or coccidiocidal, in which coccidia are killed during their development. Some anticoccidial drugs may be coccidiostatic when given short-term but coccidiocidal when given longterm. Most anticoccidials currently used in poultry production are coccidiocidal.

Best Anticoccidial Drugs For the Treatment of Coccidiosis:

Still, the mode of action of various anticoccidial drugs is not fully known. Some best anticoccidial drugs are mentioned below that are normally used in the treatment of Coccidiosis.

  • Amprolium
  • Quinolines
  • Clopidol
  • Sulfonamides
  • Ionophores (monensin, salinomycin)
  • Toltrazuril
Treatment of Coccidiosis in Poultry

Prevention and Control of Coccidiosis

Every problem can be treated by adopting some precautionary protocols some of these are

  • Make sure water is clean and fresh
  • Keep feeders clean and dry and don’t throw food on the ground where it can be contaminated
  • Ensure brooder chicks or chickens have enough space – coccidiosis will take off in an overcrowded area. Chickens need four square feet of space each in their coops
  • Provide medicated starter feed for baby chicks. If your chicks have been vaccinated against coccidiosis, don’t give them medicated starter feed, it will simply cancel out their vaccination.
  • If you live in a particularly wet area consider giving amprolium as a preventative. You can buy it over the counter from vets, produce stores, or pet stores easily


Coccidiosis in Poultry is a common intestinal disease in avian species. Poultry birds are very prone to health issues, but every problem can be treated if you know all the protocols about that disease. The best way to prevent Coccidiosis in Poultry is to control the life cycle of coccidia. The coccidial parasite becomes infective if the environment is suitable for its growth. The prime estate for its growth is near moist places like waterers and feeders. So, make sure the water is clean and fresh. Keep feeders clean and dry. Keep your birds fully vaccinated to avoid any consequences in the future. 

Have you vaccinated your Birds? Let me know in the comment below.

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