ABSTRACT
The water mite Unionicola niloticus (Aboul-Dahab, 1998) is
commonly parasitizing the molluscan host Anodonta rubens. It has a
powerful pedipalp used for host attachment, making rooms for embryos and
feeding process. The action of the pedipalp causes displacement, rupture,
erosion and cellular reactions in the host gill tissue. The cellular reactions
include infiltration and accumulation of leucocytes in different parts of the
gill tissue, causing edema, formation of large numbers of brownish and
yellowish bodies scattered in different areas of the gill tissue and formation
of fibrous capsules around the embryos.