COCCIDIOSIS IN SMALL RUMINANTS  

 By        SAMUEL ENGIDAW

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INTRODUCTIONEthiopia has the largest livestock and highest draft animals population in the continent.There are approximately 47.7million cattle, 21.7 million horses,5.57 million donkeys,1million camels and 48 million heads of sheep and goats. Sheep and goats are major sources of meat and cash income.They contribute quarters of domestic meat consumption, half of domestic wool production,40% of fresh skin and 92% of semi processed skin export trade. Diseases, poor nutrition, poor breeding policies and poor management are major constraints for decreased production.Coccidiosis is one of the protozoan disease that affects them.There are different species of genus Eimeria that causes the disease.The disease is host specific and mostly affects young lambs and kids .

OBJECTIVES

To understand the taxonomical classification of Eimeria.The etiology and its different species.To review the lifecycle,epidemiology,clinical signs,pathogenesis,dignosis,treatment,and prevention.

TAXONOMICAL CLASIFICATION

   

Protozoa

Sporozoea

Eucoccidiidae

Sarcomastigophora Sporozoa Ciliophora microspora

Eimeria

Eimerina

Eimeridae

phylum

Genus

Family-

Sub order

Order

Class

Sub phylum

Etiology

Coccidiosis is caused by protozoans of genus Eimeria.They are highly species specific.

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goat sheep

E.alijevi E.crandallis

E.ninakohlyakimova E.faurei

E.christenseni E.ahsata

E.hirci E.intricata

E.caprovin E.ovina

E. aspheronica… E.ovinoidalis…

E.arloingi and E.ninakohylakimovae are most pathogenic

E.ovina and E. ahsata are known to be pathogenic in sheep

Life cycle•The life cycle of coccidia can be divided into two phases:endogenous phase and exogenous phase.

Endogenous phase ©During the endogenous phase the parasite undergoes numerous divisions in the intestinal cells. •The sheep ingests the sporulated oocysts with contaminated feed or water.•The sporulated oocysts release sporozoites in intestinal lumen(excystation) .

Endogenous phase…. Each sporozoite actively penetrates into epithelial cells and transfers into trophozoite and then to schizont.The schizonts will contain multitude of merozoites Each merozoite produce secondary schizontThese secondary schizonts then form second generation merozoites (schizogony)Second generation merozoites penetrate into epithelial cell of large intestine to initiate sexual development to form macro and micro gamonts(gamogony) .

Endogenous…

• Fertilization of the macrogamete by the microgamete forms a zygote which further forms an oocyst.•The oocyst breaks out of the host cell into the intestinal lumen and excreted with faeces

Exogenous phase This phase takes place outside of the body in the environmentunsporulated oocysts which are passed out in the faecal material of the sheep sporulate under optimal environmental conditions.

Unsporulated oocyst

4 sporocysts( an oocyst)

8 sporozoites(sporulated oocyst)

merozoites

Micro gametocyte

macrogametocyte

oocyst

out

Internalenvironment

Oocyst ingestion

Oocyst excretion

External env’t

Unsporulated oocyst4 oocyst

Infectious stage

Life cycle of ovine coccidia

EpidemiologyCoccidiosis of small ruminants is present any where in the world.It affects mostly young lambs and kids.Adult animals are highly resistant to disease, but not totally resistant to infection.Sporulated oocysts are resistant to heat and desication,viable for up to 10 months in faecal sediments. Humid tropics are favourable for the survival and development of coccidian throughout the year.

Pathogenesis

©The pathogenesis depends on * developmental stages of the parasite in the intestine.* The number of oocysts ingested, * species of Eimeria present, * age and immune status of the host

©Severe damage to the intestinal mucosa cause Increased rate of peristalsis Malabsorption and diarrhea which is followed by dehydration

and acidosis Damage to the epithelial cells of intestine

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Clinical signs

©Subclinical coccidiosis should be suspected during complaints of¨poor growth, ¨weight loss

©In acute cases early signs include *decreased appetite* weakness, fever,* ocular and nasal discharges *abdominal pain and persistent straining in an attempt to pass feces,.

©Peracute cases are caused by severe blood loss in the intestinal lumen,

may case sudden death before signs of diarrhea.

Necropsy findings

It offers more reliable indication of clinical coccidiosisThe most consistent and characteristic lesion is

The occurrence of multiple raised, white nodules on the intestine mucosa

*In per acute cases, the intestinal lumen may contain fresh blood.*The caecum is usually inflammed empty,contracted,edematous and thickened

 Diagnosis

¨Faecal samples from lambs (pasty or watery) can be taken directly from rectum¨Scraping of lesions should be mixed on a slide with little physiological saline solution and examined microscopically¨The mere presence of oocysts in the faces is not ground for diagnosis of coccidiosis.

The only sure way to diagnose coccidiosis is finding of lesions containing coccidia at necropsy.

Treatment

*Anti coccidian drugs in individual animals may have limited value *Drugs used for treatment of coccidiosis are:

Sulfonamides- Sulfadimethoxine,Sulfadimidine,Sulfamethazine..Antibiotics-Amprolium,NitrofurazoneIonophores-Monensin,Lasalocid,salinomycinQuinolons-Decoquinate

*Supportive care is the principle therapeutic intervention in acute case of coccidiosis.*Diarrhoeic goats should be removed from group and given oral or parentral balanced electrolyte solution.

Prevention

©Feed lots should be kept dry and clean.©The feed trough should be constructed high enough so that there is no wastage from it and they are not contaminated by faeces.© Avoid overcrowding.©Keep bedding as clean and dry as possible (coccidia survive best in moist conditions).©Avoid following-on young lambs behind behind older lambs at pasture©Ensure lambs have sufficient colostrum and nutrition

Conclusion and recomendation

*In general Coccidiosis which is caused by Eimeria species is the most important disease that cause morbidity and mortality in both sheep and goats*It is a self limiting disease which is widely distributed throughout the world.*It mostly occurs and affects young lambs and kids which are in intensive husbandry and under stress condition.*Necropsy examination offers most reliable indication for diagnosis of clinical coccidiosis

Conclusion…Based on the above the following points are recommended:

There should be proper management of sheep and goats to avoid pre disposing factors for the occurrence of the diseaseTry to reduce the disease incidence through avoidance of overcrowding and stress.Attention should be given for the hygienic system of housing and feedingPrevention should be given more attention than treatment.

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