Study on prevalence of Dicrocoelium dendriticum in animals slaughtered in north of Iran

Objectives: Dicrocoelium dendriticum’s life cycle is complex and unusual. Adults are found in the bile ducts of sheep, cattle and goats. Eggs that passed out of the definitive host will be ingested by terrestrial snails. In the snail sporocysts develop and cercariae are passed out of the snail in a mucus-like substance as "slime balls." These "slime balls" will be eaten by ants, where metacercaria will develop in this second intermediate host. Eventually these ants will be ingested by grazing animals and the life cycle will be completed. Materials & Methods: This study was carried out descriptively and prospectively given the slaughter charts for year 2009 in Mazandaran industrial slaughterhouses. The information presented in the charts was transferred to the tables designed according to desired variables such as the kind and the number of the slaughtered animals, kind of the parasite, the number of the infected domestic animals, month and season. This information was analyzed statistically. Results & Conclusion: In this paper, the prevalence of Dicrocoelium dendriticum was investigated and it was concluded that 20733 out of the total number 519929 slaughtered animals including 13606 sheep, 4914 goats and 2213 cattle had been infected by this parasite. Infection rate was (4%). In general, the highest prevalence rate was found in the autumn. The prevalence rate of infection in sheep (4.3%) was higher than cattle (2.54%) and goats (4.2%). Once Dicrocoelium infestation is established it will be quite difficult to be controlled. Ant or snail control is not practical in most pasture .The possibility of eggs surviving freezing and the fact that rabbits may be infected complicates the control plan. The best measures to avoid Dicroecoelium are keeping animals from areas known to have high fluke levels, exerting pasture rotation and regular deworming. If at all possible, keeping sheep off the pasture in cold weather should decrease the number of infected ants consumed.