Taenia ovis in Small Ruminants in Iran: Prevalence, Pathology, and Economic Loss

Taenia ovis larvae can result in economic losses in small ruminants due to condemnation of infected tissues or whole carcasses. From 2017 to 2018, the T. ovis prevalence in 16,180 sheep and 7560 goats at the Najafabad slaughterhouse in Isfahan was determined. More sheep (477; 2.9%) than goats (90; 1.2%) were found to be infected, and the prevalence was higher in animals <1 y (p < 0.0001), and higher in spring in sheep (8.2%) and goats (2.2%). Female sheep were more frequently infected than males (p < 0.0001); this did not hold true for goats. Of the tissues examined, T. ovis was found more often in the heart muscle of sheep compared with other tissues; however, infections in the heart muscle, masseter muscle, diaphragm, and triceps were similar in goats. Granulomas and caseous necrosis in the heart muscles were associated with the accumulation of mononuclear inflammatory cells and the formation of fibrous tissue around the parasite. Based solely on infected tissues found in this study, the economic loss caused by the presence of T. ovis larvae was estimated to be 4167 United States dollars (USD). Control methods, such as proper disposal of infected tissues and anthelmintic treatment of infected dogs, are necessary to decrease infection and prevent economic loss in small ruminants.