Prevalence and Long Term Trend of Liver Fluke Infections in Sheep, Goats and Cattle Slaughtered in Khuzestan, Southwestern Iran

Liver fluke infections in herbivores are common in many countries, including Iran. Meat-inspection records in an abattoir located in Ahwaz (capital of Khuzestan Province, in southwestern Iran), from March, 20, 1999 to March, 19, 2008 were used to determine the prevalence and long term trend of liver fluke disease in sheep, goats and cattle in the region. A total of 3186755 livestock including 2490742 sheep, 400695 goats and 295318 cattle were slaughtered in the 9-year period and overall 144495 (4.53%) livers were condemned. Fascioliasis and dicrocoeliosis were responsible for 35.01% and 2.28% of total liver condemnations in this period, respectively. Most and least rates of liver condemnations due to fasciolosis in slaughtered animals were seen in cattle and sheep, respectively. The corresponding figures from dicrocoeliosis were goats and sheep, respectively. The overall trend for all livestock in liver fluke was a significant downward during the 9- year period. The prevalence of liver condemnations due to fasciolosis decreased from 7.37%, 1.80%, and 4.41% in 1999–2000 to 4.64%, 1.12%, and 2.80% in 2007–2008 for cattle, sheep and goats, respectively. Dicrocoeliosis was less prevalent than fascioliasis, but similarly declined from 0.35 % and 0.15% in 1999–2000 to 0.00% and 0.08 % in 2007–2008 in cattle and sheep, respectively. Data showed significant seasonal pattern for Dicrocoelium dendriticum in sheep and goats, but for Fasciola spp. in different animals there were no statistically significant differences with respect to season. Liver condemnations due to fasciolosis and dicrocoeliosis were more prevalent in cattle slaughtered during summer, whereas they were higher in winter for both sheep and goats. The odds ratio showed a slightly different pattern in some years; however, the overall declining trend was still observed. This survey provides baseline data for the future monitoring of these potentially important parasitic infections in the region, and demonstrating possible long term trends.