Adults of Rhadinorhynchus ornatus Van Cleave, 1918 were collected from the small intestine of skipjack tuna, Katsuwonus pelamis (Linnaeus), in the high seas of the Pacific Ocean off the west coast of South America (new parasite locality record) and described using optical microscopy and a scanning electron microscope (SEM). Our specimens were somewhat comparable to those described from North America and Japan, but had more trunk spines. Definitive differences between the length and thickness of each of the dorsal and ventral proboscis hooks are noted for the first time, with most ventral middle hooks being relatively shorter and more robust than dorsal middle hooks. The SEM documented, for the first time, the different surface topography of the tegument in the proboscis, the neck, and in 3 trunk regions; the presence of microtrichs in the mid- and posterior trunk regions; the elevated base of trunk spines; the circular arrangement of basal proboscis hooks; the different morphology of all dorsal and ventral proboscis hooks and the striations of their surface; the ribbed surface topography of eggs; the elevated slit-like female gonopore; and the rimmed edge of the bursa. The presence of microtrichs on the tegumental surface is further supported by transmission electron microscopy studies. This is the first report of microtrichs in any species of Acanthocephala and the second report of striations in proboscis hooks. The geographical distribution of R. ornatus appears to correspond, at least in part, to that of its epipelagic primary host, K. pelamis, throughout the world in waters ranging in temperature from 14.7 to 30 C.
Fish parasites are of economic and health importance where they cause serious problems in commercial fish farms and it can be transferred to human and animals. Capillaria species are nematodes of serious fish diseases which may be transferred to human.The present study was conducted to detect the in vitro effect of sublethal concentration (LC 90) of albendazole(ABZ) and Allium sativum (garlic) cloves water extract on ultra structure of Capillaria sp. collected from fresh water catfishes, Bagrus docmac and B. bayad using SEM and TEM. The morality rates of the adult Capillaria sp. in vitro exposed to different concentrations of albendazole and Allium sativum water extract was recorded after 24 hours exposure time. A. sativum water extract had higher effect than albendazole where lower concentration of A. sativum extract (18 x10 3 ppm) gave maximum mortality rate (100%) , 24 hours post exposure. SEM studies of the cuticle of adult Capillaria sp. in vitro treated with LC 90 (17.161 x10 3 ppm) of A. sativum water extract for 24 hours revealed that it induced severe changes in the cuticle integrity more than those treated with concentration LC 90 (5.543 x 10 6 ppm) of albendazole. TEM studies revealed deformation of the cuticle, hypodermis, muscles and digestive system in worms treated with LC 90 (17.161 x10 3 ppm) of Allium sativum water extract.
Background: The structure of cordons is a principal characteristic in the identification of acuariid nematodes. The cordons of Desportesius invaginatus are formed of consecutive structurally elaborated plates of variable size and topography. Energy dispersive X-ray microanalysis (EDXMA) is an analytical technique that has been used to evaluate the element composition and crystalline nature of the body surface of cestodes, nematodes and acanthocephalans. It has been also used to measure the concentration of minor elements [sulphur (S), phosphorus (P), calcium (Ca) and potassium (K)] and trace elements (Fe, Zn). Objective: The present study was undertaken to investigate the concentration and distribution pattern of some chemical elements, namely: S, Ca and P in the cuticular elaborations of the cordon plates of D. invaginatus using dispersive X-ray spectrometry, aiming to supplement information regarding the composition and function of these structures. Results: Energy dispersive X-ray microanalysis revealed variations in the concentration of Ca, S and P in different regions of the cuticular ridges (tip, middle and base) of the three regions (anterior, middle, posterior) of the cordons of D. invaginatus. In the anterior region of the cordon, P was the highest in concentration followed by Ca then S; in the middle region, S exhibited highest concentration followed by P then Ca; while in the posterior region, S showed the highest concentration followed by Ca and P. The study revealed a specific pattern for the distribution and concentration of each element in relation to the region in the cuticular ridges of the cordons. Highest concentration of Ca and S was presented in the posterior region, where Ca decreased significantly towards the middle region to reach the lowest levels, then significantly increased again towards the anterior region; while S reached its lowest concentration in the anterior region, where P recorded its highest concentration. Conclusion: The concentration and distribution pattern of S, Ca, and P could be related to the anchorage function of the ridges. The high concentration of S in the base gives flexibility to these structures and facilitates the piercing action of the host tissue; while the accumulation of both Ca and P at the tip could result from the polymerization of both elements to give the rigidity and hardness that secure the position of the parasite in the host's tissue and prevent its detachment.
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