Aspects of the Histopathology of <i>Clarias gariepinus</i> Infected With the Camallanid Parasite <i>Procamallanus</i> ( <i>Procamallanus</i> ) <i>pseudolaeviconchus</i> Moravec and Van As, 2015

Histopathological studies of infections with the nematode Procamallanus (Procamallanus) pseudolaeviconchus Moravec and Van As, 2015, an intestinal parasite of Clarias gariepinus (Burchell, 1822), are scarce. The current study describes histopathological changes in the stomach of C. gariepinus infected with P. (P.) pseudolaeviconchus and links it to the parasite's wound-inflicting and feeding structures using light microscopy (LM) and scanning electron microscopy (SEM). A total of 20 fish were collected from the Vaal River below the Vaal Dam and Lake Heritage in the Crocodile River, Gauteng, South Africa. In Lake Heritage, the prevalence of the infection was 80%, with mean intensity and mean abundance of 2.5 and 2, respectively. Perforation and alteration of the columnar epithelial cells lining the secondary folds of the stomach mucosa, trauma to the loose connective tissue, and gastric glands were observed. Mast cell numbers did not vary in the infected and uninfected samples, indicating the absence of an initiated cellular immune response. No haemorrhage, cellular infiltration, inflammation, necrosis or granuloma formation was observed in the infected sample. The peribuccal flanges, the solid buccal capsule and the muscular oesophagus are the wound-inflicting and feeding structures.