Lamproglena Monodi Capart, 1944, Attachment Scheme and Associated Pathology on the Gills of Oreochromis Niloticus Niloticus, with a Special Reference to Thoracic Appendages PDF

Keywords

Attachment, freshwater fish, gills, Lamproglena monodi, Lernaeidae, Oreochromis niloticus niloticus, pathology.

Abstract

This work comprises a parasitological and a histopathological examination of the Nile tilapia, Oreochromis niloticus niloticus, naturally infected with Lamproglena monodi (Crustacea: Lernaeidae). Fish specimens were collected weekly from El-Minia Nile basin, Egypt (between April 2006 to March 2008). From a total of 420 fish examined, 96 (22.86%) were found infected. Attachment of L monodi was mainly enhanced by the armed maxillae that were seen deeply introduced into the underlying tissues reaching the axial cartilage of the gill filament. The maxillipeds were not involved in the attachment to the gill epithelium. Histological changes were restricted only to the free ends of gill filaments, where copepods were found attached; the central and basal parts appeared normal and their gill lamellae remained intact. Deep and shallow lesions associated sometimes with compressed or exfoliated hyperplastic epithelium were encountered in front of the cephalothorax and around oral apparatus of the parasite. In slight and moderate infections gill lamellae showed partial fusion. In many cases of heavy infection, the attacked area of gill filaments was eroded through. The cephalothorax was sometimes found in a deep cavity of the proliferated epithelium that was infiltrated by granular cells and lymphocytes