Validity, impacts and seasonal prevalence of Henneguya species infecting catfish Clarias gariepinus from River Nile, Egypt.

The validity, impacts and seasonal prevalence of Henneguya suprabranchiae infecting Clarias gariepinus from the River Nile were studied. The overall prevalence was 35% (84/240) with maximum rate of infection in spring and minimum rate of infection in summer. The development of the cyst-like plasmodia was "the intrafilamental type'. Henneguya suprabranchiae is a pathogenic species as the parasite showed high intensity of infection which led to deformation of the filament structure and complete disappearance of the gill lamellae. The validity of H. suprabranchiae compared to the other described species of the same host was discussed.

Redescription of Myxobolus niloticus Fahmy et al. 1971 infecting Labeo niloticus and their seasonal variation and histological impacts.

Redescription of Myxobolus niloticus Fahmy et al. 1971, from tail fin of Labeo niloticus is presented in this paper to complete the Fahmy et al. description. The seasonal variation and the histological impacts of the parasite are described as well. In the present work, new data on the spore morphology were obtained with the use of light microscopy, which made it possible to be redescribe. The prevalence of infection was 20.8%. The infection caused mild fin lesions, which can be negligible. The low-intensity infection found in the present study caused only minor deformity of the fins.

Myxobolus lubati n. sp. (Myxosporea: Myxobolidae), a new parasite of haffara seabream Rhabdosargus haffara (Forsskal, 1775), Red Sea, Egypt: a light and transmission electron microscopy.

A new myxosporean parasite, Myxobolus lubati n. sp., was described from the wall of the intestine of haffara seabream Rhabdosargus haffara (Forsskal 1775), Red Sea, Egypt. Macroscopic plasmodia of about 300 mum diameter were located in the circular muscle layer of the intestine. The spores were ovoid and sometimes ellipsoid and measured 9.8 x 7.2 mum. The shell wall of the spore was thickened at the posterior end and marked with 5-7 sutural markings. Polar capsules were equal and pyriform with three polar filament turns situated in the posterior half of the polar capsule. Polar capsules measured 4.2 x 1.6 mum. Histological evaluation of the infection revealed a slight distention of the intestinal layer of muscularis. Ultrastructure of the plasmodial wall and sporogenesis of the present species followed the usual pattern valid for most studied myxosporean species.