Fathy Abdel Ghaffar

Hepatozoon aegypti nov. sp. III: Electron microscope studies on the gamogony and sporogony inside the vector Culex pipiens molestus

Gamogony and sporogony ofH. aegypti were studied in the haemocoel of its vectorCulex pipiens molestus by electron microscopy. On day 2 p.i., the parasites, associated in pairs in the haemocoel, grew large and differentiated into micro- and macrogamonts within the same parasitophorous vacuole. The microgamont measured 18×10 μm and was covered by a single membrane, having micropores and some underlying osmiophilic material. On day 3 p.i. its nucleus was divided and four uni-flagellated microgametes developed. The pear-like microgamete measured 6 μm in length and mainly contained the nucleus; in a groove of the nucleus the mitochondrion and 6–8 microtubules were observed. The single flagellum measured 23 μm in length and had only single microtubules in an 8+2 or 9+1 arrangement. The macrogamont measured 25–35 μm, contained accumulations of mitochondria, endoplasmic reticulum (rough, smooth) and several Golgi apparatus. It was covered by two membranes with micropores, but the inner membrane showed some interruptions at many places. The cytoplasm of the oocyst divided into about 52 (15–75) sporoblasts on day 10 p.i. Inside sporoblasts, cristalloidal bodies were associated. Sporocysts first were seen on day 13 p.i. They had a two-layered thickened wall. On day 16 p.i. about 26 sporozoites of 9×2 μm developed inside each sporocyst. The sporozoites ofH. aegypti had the characteristic fine structure of the merozoites and stages in the red blood cells studied in the snakeSpalerosophis diadema; in addition they had two large crystalloid bodies on both sides of the nucleus.

Myxosporidia infecting some Nile fishes in Egypt

Although myxosporea have been known since the early nineteenth century, only about 1342 species belonging to 51 genera are recognized (Lore and Dykova 1992). All species of the class Myxosporea occur in ectothermic vertebrates, most of them in fishes (Post 1987). The present study deals with the prevalence of myxosporidia infecting six species belonging to three families of Nile fishes at Giza Governorate in Egypt. These fishes, which are of great economic importance, were identified as Oreochromis (syn. Tilapia) niloticus, O. aureus (family: Cichlidae), Barbus bynni, Labeo niloticus (family: Cyprinidae), Synodontis schall, and Clarias lazera (family: Siluridae). Freshly collected fishes were immediately examined externally for the presence of cysts. Then, they were dissected and the internal organs were examined including the liver, kidney, muscles, gallbladder, inner surface of the operculum and gills. Spores were stained with Giemsa stain. Measurements were applied to fresh spores using a calibrated ocular micrometer and a Zeiss research photomicroscope. Some cysts were fixed in 3% glutaraldehyde and processed as usual for light and electron microscopy which took place at the Zoology Institute, Bochum University. Descriptions and measurements were done according to Lore and Arthur (1988). The Myxosporidia species identified in this study include the following: 1. Myxobolus species 1 the hosts of this species were Oreochromis niloticus and O. aureus. The sites of infection by macroscopic cysts included the base of the gill arch, roof of the mouth, internal surface of the operculum and inner wall of the cornea (Figs. 1, 2). The infection rate was 70% (number of fishes examined, 90). The spores were mostly ovoid (Figs. 3, 4), measuring 17.9 (range, 16.2-18.9)x11.1 (10.8-12.6) gm. The anterior end was as wide as the posterior end or slightly narrower. The polar capsules were ovoid, occupying about

Electron microscope observations on Onchocerca ochengi and O. fasciata (Nematoda: Filarioidea)

Abstract The fine structure of the females and males of Onchocerca ochengi (parasitizing zebu and cattle) and of the females of O. fasciata from camels were described and compared to other filariae of the genus Onchocerca. It was shown that O. ochengi resembles O. volvulus of humans in its degree of development, while being more primitive than O. gibsoni. Besides other similarities O. ochengi attracts inflammatory cells in the way of O. volvulus and these could be a model for chemotherapeutic trials.

Transmission electron microscopic studies on the effects of toltrazuril on Glugea anomala, Moniez, 1887 (Microsporidia) infecting the three-spined stickleback Gasterosteus aculeatus.

A symmetric triazinone, toltrazuril, was tested in vivo againstGlugea anomala parasitizing the connective tissue of sticklebacks (Gasterosteus aculeatus). Naturally infected sticklebacks were incubated in toltrazurilcontaining water as intermittent therapy (3×2 μg/ml for 6 h at 3-day intervals or 3×2 μg/ml for 24 h at 2-day intervals). As seen at the ultrastructural level, the drug caused severe damage to all developmental stages ofG. anomala. When treatment was carried out for 6 h, the xenoma wall exhibited a network appearance. The multinucleate meronts showed tapering at one end and were lysed at places; disintegration of the nuclei was also observed. The sporogonial plasmodia were partially fragmented, and the dumbbell-shaped nuclei of the sporoblast mother cells showed damaged spindle fibres and lysis of the chromosomal material and nuclear membranes. The shape of the mature spores was altered as well. When treatment was done for 24 h, the xenoma wall was completely destroyed. The uni-and multinucleate meronts were completely destroyed and lacked their nuclei, and the sporogonial plasmodia were frequently totally fragmented. The development of the sporophorous vesicle stopped in many cases. In the sporoblasts and their mother cells, vacuolization of the cytoplasma and lysis of the nuclei were observed. Destroyed spores with damaged polar tubes and polaroblasts were frequently detected. It seems likely that toltrazuril could be successfully applied against Microsporidia in fish when used as intermittent therapy at low doses and with prolonged exposure.

Hepatozoon aegypti nov. sp. II: Electron microscope studies on the erythrocytic stages and schizogony inside the snake, Spalerosophis diadema

The fine structure of the different stages ofH. aegypti inside its hostSpalerosophis diadema was studied. The ultrastructure of the merozoites is similar to that of the differentiated parasites (=gamonts) in the erythrocytes; all showed the general architecture of the motile stages of the Coccidia. The merozoite (9×2 μm) was covered by a pellicle of two layers; the inner layer was interrupted at the polar ring and the micropore. The parasite had a conoid, rhoptries, and a large number of micronemes (127–135). Both rhoptries and micronemes were usually found on both sides of the nucleus. The merozoite (and its adult intraerythrocytic stage: the gamont=13–16×3 μm) was characterized by 73–75 subpellicular microtubules and all the typical cytoplasmic organelles as mitochondria, Golgi apparatus, endoplasmatic reticulum (rough and smooth), some amylopectin granules and a few lipid droplets. Schizogony ofH. aegypti took place exclusively in the endothelial cells of the lung capillaries producing about 15–40 merozoites by ectomerogony.

The fine structure of cysts of Sarcocystis moulei from goats

Sarcocysts are often found in muscles of naturally infected goats. The original name Sarcocystis moulei, given by Neveu-Lemaire in 1912, did not differentiate between macroscopically and microscopically visible cysts. Transmission experiments have shown that at least two species with microscopic cysts exist in addition to those with macroscopic ones. Fischer (1979), Heydorn and Haralambidis (1982), and Heydorn and Unterholzner (1983) have described the life cycles of S. capraeanis and S. hircicanis, both of which species use the dog as final hosts. Apart from biological differences, these two species have significantly different cyst walls; this has been proven by electron microscopy (Aryeetey et al. 1980; Mehlhorn et al. 1985), although it can be seen even by light microscopy. S. capracanis forms upright, palisade-like protrusions in its primary cyst wall, whereas S. hircicanis is provided with flat, hair-like protrusions. The present study deals with the ovoid, macroscopically visible cysts of S. moulei. Such cysts were obtained from natural infections in Egypt, Saudi Arabia, and Afghanistan (provided by Dr. P. Kirmse) and from goats that were experimentally infected by cat-excreted sporocysts (after being fed with macrocysts; Heydorn and Kirmse 1989). For the fine structural analysis the cysts were taken from the goats muscles, fixed, and processed for electron microscopy according to our usual techniques, described elsewhere (Mehlhorn et al. 1976). The cysts studied were ovoid, with a length of about 3-12 ram, and appeared whitish before embedding due to their secondary cyst wall. On electron micrographs, the intracellular cysts were bound by a typical primary cyst wall containing numerous unthickened places (Figs. 1, 2). The primary cyst wall was folded, thus giving rise to many

The Efficacy of Extracts from Plants – Especially from Coconut and Onion – Against Tapeworms, Trematodes, and Nematodes

Nematodes and cestodes are present in almost all animals and humans. These parasites spread to a considerable degree among animals that are continuously grazing because in the case of nematodes, the eggs or larvae excreted in the feces leas to and immediate subsequent infection when they are ingested orally with food. Infections also occur very simply in the case of tapeworms, even though in most cases intermediate hosts are involved, which are likewise infected by the egg-or larvae-containing piles of feces of infected grazing phase, particularly when the animals stay close together, for example in mass production farms. Infestations with nematodes and cestodes are therefore a major problem threatening the rearing of livestock animals, ruminants in particular, because of the reduction in weight related to the amount of worms. The present chapter gives an overviews on the efficiency of various plant extracts on trematodes, tapeworms and nematodes. In detail it is described, that extracts of onion bulbs and of coconut–given at the same time-are able to control infections due to platyhelminths and round worms in animals. These experiments are so convincing that products may become lounched soon onto the agricultural markets.