Lernaea species are crustacean, copepod parasites that can infect and cause disease and mortality in many types of freshwater fishes, especially wildcaught and pond-raised species (both cultured and natural populations). L. cyprinacea (commonly known as Anchor worm), a parasitic cyclopoid copepod, is found worldwide; mostly in cyprinids. Several species (~110 species) of lernaeids (Lernaea and Lernaea-like parasites) have been described and L. cyprinacea, is one of the more common among them (1). The economic importance of lernaeids has increased in several parts of the world as the cause of one of numerous diseases among most farmed fish species; especially fingerlings, leading to death even with only a small number of infested lernaeids (2-4). Death of fish and/or associated damage is relative to the rate of parasitic infestation (5). Infestations occur more commonly in stagnant or slow-moving water bodies. L. cyprinacea, exhibits little host specificity and has been reported previously from a variety of freshwater fishes, frogs, frog tadpoles, and adult and larval salamanders. Although infestations are common in cyprinids, including koi, goldfish, and other related carp, numerous other freshwater species are susceptible (6-8). Lernaea species have nine stages in their life cycle, including three free-living naupliar stages, five copepodid stages and one adult stage. During development, the different stages live on and off the fish. After mating, the male copepod dies and the female bores into fish tissue, eventually using a large anchor anterior end "head" to permanently embed into the skin and muscle of the fish (9,10). This direct life cycle can take from 18 to 25 days to complete and only a fish (or an amphibian) is necessary for Lernaea spp. to develop from egg to mature adult. Common sites of Lernaea infestation include the skin, fins, gills, and oral cavity. Large numbers of lernaeids in their copepodid stages can kill small fish by damaging their gills and interfering with their breathing. Fish can survive with Lernaea infestation, but chronic conditions frequently result in poor growth and debilitation; the fish become more susceptible to secondary infection by bacteria and fungus which ultimately kills them (11-14) .

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During an investigation on intestinal flukes of cattle egret, Ardeola ibis ibis excysted metacercaria and adult worms belonging to family Echinostomatidae Nephrostomum ramosum were recovered. The tegumental surface of N. ramosum was described for the first time using scanning electron microscopy (SEM). SEM observations of excysted metacercaria and adult worms showed some basic differences, excysted metacercaria is conical shaped, ventrally curved, the oral sucker is not developed and the ventral sucker is located in the anterior third of the body, while adult worm has an elongated body with a distinct head collar at the central of which is located on the subterminal oral sucker. The oral and ventral suckers are located closely in the anterior fifth of the body. The total number of collar spines is 40 including five end group ones on each ventral corner. The tegument of the body is wrinkled with transverse grooves and is devoid of spines. The surface of whole body is lacking sensory papillae except the dorsal area of the cephalic region. The results reveal that the characteristic features of N. ramosum, including the number and shape of collar spines, the corrugated surface of the body, absence of tegumental spines and distribution of papillae differed from other echinostomes.

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Porrorchis indicus is an endoparasite of the Egyptian birds, Centropus Senegalensis aegyptius. This parasite causes damage to the gut wall of the infected birds. Spermiogenesis and sperm ultrastructure have been widely used in the phylogeny of parasitic platyhelminthic and acanthocephalan worms. However, there are limited ultrastructural data available on spermiogenesis and the spermatozoon on the acanthocephalan family, plagiorhynchidae to which P. indicus belongs. The present study investigated the ultrastructure features of the different stages of P. indicus spermiogenesis. The morphology and anatomy of the spermatozoa was described in comparison with the previous reports. Different ultrathin sections of the body of P. indicus (testes and vas deferens) were cut using transmission electron microscopy (TEM) to describe the different stages of the spermiogenesis as well as both morphology and anatomy of spermatozoa.The results showed that the primary spermatocystes of P. indicus was rounded shape with large rounded nuclei and high nucleocytoplasmic ratio. The secondary spermatocystes showed nearly ovoid shape; each possessed a small nucleus and numerous mitochondria. The early spermatid possessed a large nucleus and contained a single centriole. The early spermatid showed a posterior bulb in which the centriole had a flagellum with 9+0 pattern surrounded by a plasma membrane it changed into 9+2 pattern. The cytoplasmic canal is characterized by a ring form which appeared around the axoneme. The anterior extremity of the spermatozoa showed the presence of the centriolar derivative that had three different stages. The first is made of nine peripheral elements. The second is of nine peripheral and one central element. The third showed nine peripheral and two central elements. The centriolar derivative is followed by a flagellum with a 9+2 pattern. In mature spermatozoa, protein granules different sizes, numbers and shapes were recognized.

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