Invasive Amirthalingamia macracantha (Cestoda: Cyclophyllidea) larvae infecting tilapia hybrids in Israel: a potential threat for aquaculture.

Larvae (metacestodes) of gryporhynchid tapeworms (Cestoda: Cyclophyllidea) are reported for the first time from the liver of tilapia hybrids (Oreochromis aureus × O. niloticus) reared in earth ponds in northeastern Israel (along the Jordan River). This is the first record of Amirthalingamia macracantha (Joyeux & Baer, 1935), a parasite of cormorants (Phalacrocoracidae), outside Africa and outside the tropics. Larvae found in the liver of tilapias (Cichlidae) were identified to species level because they possessed 20 massive rostellar hooks of 3 types, with the 4 largest hooks measuring almost 500 µm. Molecular data confirmed species identification. The possible route of introduction to Israel of this African parasite, which is large (length up to 2 cm) and potentially pathogenic for cultivated tilapias, is discussed.