Parasitological and pathological findings of coccidiosis in an experimental infection caused by Eimeria ahsata in lambs

Document Type : Research Article


1 Graduate student of the Veterinary Parasitology, Faculty of Veterinary Medicine, Ferdowsi University of Mashhad, Mashhad, Iran.

2 Department of Pathobiology, Faculty of Veterinary Medicine, Shahrekord University, Shahrekord, Iran.

3 Department of Pathobiology, Faculty of Veterinary Medicine, Ferdowsi University of Mashhad, Mashhad, Iran.


    This study was conducted to investigate the pathogenesis process of E. ahsata and its morphological, pathological, and distribution of lesions in the involved tissues during 42 days of infection. Twelve lambs were randomly divided into two groups including the control and the infected groups after confirmation of their health. The animals in the experiment group were orally infected with 1× 105 sporulated oocysts. From 7 days after inoculation (DAI), the feces were sampled and oocysts per gram of feces (OPG) were individually examined for each lamb. . At 7, 14, 21, 28, 35, and 42 DAI, one lamb from each group was necropsied and the abomasum, small and large intestine, mesenteric lymph nodes, spleens, and livers were grossly investigated. From 21 to 42 DAI, mild to severe clinical lesions such as congestion and edema were seen on the mucosal surface of the small intestine associated with white and small foci about 1-2 mm, especially jejunum and ileum. From 7 DAI to the end of the study various stages of the parasite life cycle, infiltration of inflammatory cells, epithelial hyperplasia of villi, and destruction of villi epithelium were seen.  The results showed that E. ahsata was pathogenic in lambs and the macro and microscopic lesions were mostly seen in the jejunum. 


1. Molina JM, Ruiz A. Coccidiosis in sheep. In: J.P.Dubey (Eds) .Coccidiosis in livestock, poultry, companion animals and human. Taylor & Francis Group: CRC Press; 2017.
2. Bangoura B,  Bardsley KD.  Ruminant Coccidiosis. Vet Clin North Am Food Anim Pract. 2020; 36: 187-203.
3. Taylor MA, Coop RL, Wall RL. Veterinary Parasitology 3rd ed. Blackwell Publishing, 2007.
 4. Khodakaram-Tafti A, Hashemnia M. An overview of intestinal coccidiosis in sheep and goats. Revue Méd.Vét. 2017; 168: 1-3.
5. Wang CR,  Xiao JY, Chen AH , Chen J, Wang Y, Gao JF, Zhu XQ. Prevalence of coccidial infection in sheep and goats in northeastern China.Vet.Parasitol. 2010; 174: 213-217.
6. Jolley WR, Bardsley KD.  Ruminant coccidiosis. Vet. Clin. Food Anim. 2006; 22: 613-621.
7.  Heidari H. Identification of Eimeria species in sheep of Hamedan suburb, Iran J Vet Res. 2011; 66: 165-167. 
8.  Hashemnia M, Rezaei F, Chalechale A, Kakaei S, Gheichivand S. Prevalence and intensity of Eimeria infection in sheep in western Iran. Int J Livest Res. 2014; 4:107-112.
9. Mirzaei M, Dahmardeh E. The Prevalence of Eimeria Species in Sheep in Zabol city, Iran. Iran Vet  J. 2016; 11:98-105.
10.  Eckert J, Taylor M, Catchpole J, D. Licois, P. Coudert, Bucklar H. Identification of Eimeria species and strains: Morphological characterization of oocysts. In:J. Eckert, R. Braun, M.W. Shirley, P. Coudert, P. (Eds)  COST 89/820 Biotechnology—Guidelines on Techniques in Coccidiosis Research. European Commission Directorate-General XII, Science, Research and Development: Agriculture Biotechnology, Luxembourg, 1995. pp.103–119.
11. Joachim A, Altreuther G, Bangoura B, Charles S, Daugschies A, Hinney B, Lindsay DS, Mundt HC, Ocak M, S. Sotiraki. W A A V P guideline for evaluating the efficacy of anticoccidials in mammals (pigs, dogs, cattle, and sheep). Vet .Parasitol. 2018; 253: 102–119.
12. Gregory MW, Catchpole J. Ovine coccidiosis: the pathology of Eimeria crandallis infection. Inter.J.Parasitol.1978; 17:1099-1111.
13.  Bangoura B, Daugschies A. Parasitological and clinical parameters of experimental Eimeria zuernii infection in calves and influence on weight gain and haemogram. Parasitol Res. 2007;  100:1331–1340. 
14.  Reilly JS. Euthanasia of Animals Used for Scientific Purposes. Anzccart press, 2001. 
15. Hidalgo-Argüello MR, Cordero-Del-Campillo M. Epizootiology of Eimeria ahsata coccidiosis in León (Spain). Vet.Parasitol. 1988; 27: 183-191.
16. Catchpole J, Norton C, Joyner L. Experiments with defined multispecific coccidial infections in lambs. Parasitol. 1979;  72: 137-147. 
 17. Smith MN, Davis LR, Bowman GW.  The pathogenicity of Eimeria ahsata, a coccidium of Sheep. J.Protozool. 1960; 7: (Suppl.), 8.
18. Mahart JL, Sherrick GW. Coccidiosis due to E.ahsata in feedlot lambs in Illinois. J. Am. Vet. Med. Ass. 1965; 146: 1415–1416.
19. Chartier C, Paraud C. Coccidiosis due to Eimeria in sheep and goats, a review, Small Rumin. Res. 2012; 103: 84-92.
20. Stockdale PHG, Bainborough AR, Bailey CB, Niilo LM. Some pathophysiological changes associated with infection of Eimeria zuernii in calves. Can J Comp Med.1981; 45: 34–37.
21. Enemark HL, Dahl J, Enemark JM. Eimeriosis in Danish dairy calves--correlation between species, oocyst excretion and diarrhoea. Parasitol Res. 2013; 112: 169–176.
 22. Hashemnia M, Khodakaram-Tafti A, Razavi SM, Nazifi, S. Experimental caprine coccidiosis caused by Eimeria arloingi: morphopathologic and electron microscopic studies. Vet. Res.Com. 2012; 361:47–55.
23. Khodakaram Tafti A, Mansourian M. Pathologic lesions of naturally occurring coccidiosis in sheep and goats. Comp Clin Pathol. 2008; 17: 87–91.
24. Buret A, Gall DG, Nation PN, Olson ME. Intestinal protozoa and epithelial cell kinetics, structure and function. Parasitol Today.1990; 6:375–380.
 25. Aleksandersen M, Landsverk T, Gjerde B, Helle O. Scarcity of γδ T Cells in intestinal epithelia containing coccidia despite general increase of epithelial lymphocytes. Vet .Pathol. 1995; 32:504-512.
26.  Khodakaram.A. Ileoileal intussusception associated with coccidiosis in sheep. B. J.Vet.Med. Series B, 1995;46 : 659–663.
27. Taghavi-Razavizadeh A, Nourani H, Razmi G, Zarif MBH. A Report of unusual diffuse nodular lesions in intestines of Lambs with Coccidiosis. Vet ClinPathol.2016; 39: 251-254.
 28. Daugschies A, Bürger HJ, Akimaru M. Apparent digestibility of nutrients and nitrogen balance during experimental infection of calves with Eimeria bovis. Vet Parasitol.1998; 77: 93-102
 29.] Jubb KVF, Kennedy PC, Palmer N. Pathology of domestic animals. Academic Press Inc,2007.
30.  Daugschies A, Najdrowski M. Eimeriosis in cattle: current understanding.   J Vet Med  Series B.2005; 52: 417-427.