Pathological and parasitological investigations of eels [anguilla anguilla] naturally infested with anguillicola crassus and pseudergasilus zacconi in Egypt

ABSTRACT

For the first time in Egypt Anguillicola crassus and Pseudergasilus zacconi were recognized and identified from Anguilla anguilla. The naturally diseased fish showed skin hemorrhages, low body gain and occasionally abdominal swelling. In anguillicolosis, the infected swim bladders showed great thickening of their wall and multiple areas of hemorrhages together with the presence of round worms floating in chocolate like material within their luminae. The prevalence of infection was 30% and the intensity of parasite ranged from 1- 15 worms per fish. Histopathologically, cross sections of adult worms and numerous ensheathed larvae were present inside the lumen of the examined swim bladders. Severe congestion, submucosal hemorrhages and mononuclear cellular infiltration were recorded. Epithelial hyperplasia and desquamation with fibrosis of the swim bladder wall were also detected. In pseudergasilosis, the gill lesions were represented by excess mucous secretion with presence of grayish white elongated nodules firmly attached to the gill filaments. Microscopical examination of the gills revealed presence of parasitic elements in-between destructed gill filaments with diffuse hemorrhages, mononuclear cellular infiltration and fusion of gill lamellae. The morphological description used in identification of recognized parasites is discussed in the text