E. Ahmadiara - Department of Parasitology, Faculty of Veterinary Medicine, University of Tehran, Tehran, Iran
S.H Hosseini - Department of Parasitology, Faculty of Veterinary Medicine, University of Tehran, Tehran, Iran
F Jalousian - Department of Parasitology, Faculty of Veterinary Medicine, University of Tehran, Tehran, Iran
H.A Ebrahimzadeh Mousavi - Department of Aquatic Animal Health, Faculty of Veterinary Medicine, University of Tehran, Tehran, Iran

BACKGROUND: The plerocercoid stage of Pseudophyllidean cestoda infected a wide range of fresh water fish, particularly the members of the Cyprinidae family. The parasite species are the most common pathogens that have severe effects on fish. OBJECTIVES: The aim of the present study is todetermine the occurrence and distribution of the plerocercoid of Diphyllobothriidae in two freshwater fish from north and northwest of Iran. Finally, we discuss the role and dynamics of these species of fish in the transmission of infection. METHODS: This study was carried out from September 2011 to September2012on a total of 883 A. bipunctatus and 418 A. brama from north and northwest of Iran. The samples were analyzed to find the plerocercoid infection. RESULTS: From a total number of 883 A. bipunctatus and 418 A. brama fish samples, 558 fish (63.19%) of the former and 67 fish (16.02%) of the latter were infected. The rate of infection was significantly lower in winter (p<0.01). Also, the weight of infected fish was significantly lower than noninfected ones (p<0.01). Moreover, the infection in northwest of Iran was significantly higher than north of Iran (p<0.01). CONCLUSIONS: The family of Diphyllobothriidae is an important cestode and the prevention programs to break the cycle of infection are essential. More suitable solutions to tackle the problem, further epidemiological studies on other fresh water sources of Iran are needed.

diphyllobothriidae, Abramis brama,Alburnoides bipunctatus, north andnorthwest of Iran