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Parasitic fauna of marine molluscs.

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Parasitic fauna of marine molluscs. Within the phylum mollusca, trematode parthogenetic generations take place (sporocyte and rediae); these molluscs are only the intermediate hosts for these trematode parasites. Development of these stages takes place within the gonad and the digestive gland of the host. This can have devastating results upon the host species because there is a constant battle going on within the host to gain energy and resources and also for the parasite within its habitat (the host) to gain energy and recourses. A consequence of this is the parasite usually wins the battle and the host undergoes histochemical and biochemical changes. These changes can include stunted growth due to only gaining the energy and recourses that are left after the parasite has gained what it requires. Gigantism can also occur in the host whereby it undergoes rapid growth after the host gains much energy and resources after castration, thus a sacrifice. ...read more.


Gently take one sample at a time and gently tap with a hammer and remove the shell. Cut of the foot and mount the visceral hump on a glass slide. Using another glass slide gently press down on the other slide to spread out the sample. Under the light microscope examine the sample for infection and record the stage at which infection is occurring and the trematode that is infecting the sample. Carry out the procedure for all of the samples. Results Fig1 Percentage of infected and uninfected and determination of parasite Parasite Species Littorina littorena Infected Littorina saxitilis Infected Value of X2 X2 ? 3.841 P> 0.05 Cryptocotyle lingua 88 19 2.16 Not significant Himasthla spp 1.7 4 1.06 Not significant Microphallus similis 19 11 0.23 Not significant Cercaria emasculans 16 7 0 Not significant C. ...read more.


Hence there is no specificity by the parasites found in the size and habitat type of their host. It seems likely that they are not infecting host species based on these two factors. Conclusion It seems evident that the two parasite species above would be worthy of further study to determine the reason why in this investigation they seemed to have host specificity for L. saxitilis. (Fig2) Evidence in this observation showed that it was not the size of the host or their particular (Fig3)habitat type that determined the infection. Hence another possible environmental factor may be influencing these particular parasites to infect L. saxitilis. There could possibly be factors such as temperature, desiccation, and salinity of the water that are influencing these results. It may become apparent with further study that there may well be some kind of host-parasite combination with their own set of rules associated with some other ecological and physiological factors. This may have laid the path to their possible co-evolution (Gorbushin and Lerakin 1999). ...read more.

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