Ultrastructural characteristics and histological impacts of Myxobolus naffari (Myxozoa: Myxosporea) infecting Nile labeo Labeo niloticus (Osteichthyes: Cichlidae)

Abstract

We describe the ultrastructural characteristics and histological impacts of Myxobolus naffari Abdel-Ghaffar et al., 1998, which infects the Nile fish Labeo niloticus. The prevalence of infection was 65%, with the maximum rate occurring during winter and a lower rate during summer. The histological impacts were manifested as a fusion of the gill epithelia, hyperplasia at the ends of the plasmodia, and atrophy of the external surface of the plasmodia. The ultrastructural study revealed that the plasmodial wall was composed of a single unit membrane and bound externally by a thick layer of collagen fibers. The earliest recognizable stage was the disporous pansporoblast. The development of the parasite was asynchronous, with mature and immature spores randomly distributed throughout the plasmodium. © Inter-Research 2010.