Study on the role of age, sex and season on the prevalence of fascioliasis and dicrocoeliasis in animals slaughtered in Tabriz slaughterhouse

Liver trematodes, including Fasciola and Dicrocoelium species, are zoonotic parasites that cause high mortality and economic losses in ruminants. This study aimed to investigate the effect of age, sex, and season on the prevalence of fasciolosis and dicrosliosis in slaughtered animals in the Tabriz slaughterhouse. During two years, livers of 4150 cows, 500 buffaloes, 2000 goats, and 5000 sheep were examined for the presence of Fasciola hepatica, Fasciola gigantica, and Dicrocoelium dendriticum by incisions on the liver and ocular observation. The results showed that 5.4%, 16%, and 6% of slaughtered cows, sheep, and goats were infected with liver trematodes (P<0.05), respectively. Of the 500 buffaloes studied, no liver trematode was isolated. The prevalence of parasitic infection in all three animals increased significantly with the age (P<0.05). In female cows and sheep, the rate of liver trematode infection was significantly higher than in males (P<0.05). The highest and lowest prevalence was observed in summer in spring, respectively. The highest frequency of parasites and severity of infection in all studied animals was related to Dicrocoelium dendriticum and the lowest was related to Fasciola gigantica (P<0.05). Based on the market day price, the number of economic losses due to the condemnation of liver of cows, sheep, and goats due to trematode infections were estimated at 402,240,000 (3656.72 USD), 576,576,000 (5241.6 USD), and 28,545,000 (259.5 USD) RIAL, respectively. Due to the history of the human fascioliasis epidemic and economic damage caused by liver condemnation in this area, effective control methods are suggested.