Some studies on metacercarial infection in oreochromis niloticus in Assiut governorate and their role in transmission of some trematodes to dogs

الملخص EN

A total number of 400 Oreochromis niloticus (Tilapia nilotica) were investigated for parasitological studies on various encysted metacercariae of digenetic treaties in different body parts of the examined fish specimens in Assiut Governorate.

The total prevalence of infected Oreochromis niloticus with different encysted metacercariae was 84.75%.

They were differentiated into two types: The first type was microscopic encysted metacercariae, their prevalence rate was 78.25%.

They were distributed between muscle fibers of the trunk, tail and head regions.

The second one was clinostomatid metacercariae, their prevalence rate was 62.25%.

The branchial chamber was the most common habitat of infection where their infection rate was 47.5% followed by kidneys 13.25% then skin 1.5%.

The detected clinostomatid metacercariae were differentiated into four species: Clinostomum phalacrocoracis, Clinostomum tilapiae, Euclinostomum ardeolae and Euclinostomum heterostomum.

Microscopic encysted metacercariae were differentiated into Prohemistomum vivax and Haplorchis spp.

The incidence, distribution and intensity of the encysted metacercariae in different regions of the examined fish were studied.

Experimental infection was carried out to confirm the identification of different kinds of microscopic encysted metacercariae by feeding parasite free puppies with different encysted metacercariae collected from the muscles of Oreochromis niloticus.

Two types of adult digenetic treaties were recovered from the intestinal mucosa (5-7 days post infection): The first type is Prohemistomum vivax and the second type is Haplorchis yokogawai.