Studies on the Effects of Ultraviolet Radiation on Schistosoma Mansoni
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Date
1988
Authors
Ariyo, A.A
Journal Title
Journal ISSN
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Publisher
University of Lagos
Abstract
The effect of ultraviolet radiation on the pre-adult stages of Schistosoma mansoni under various conditions was studied. No morphological changes occurred in irradiated eggs. However, the hatchability of the eggs decreased proportionately with the radiation dose. The mean rates of motility of miracidia hatched from irradiated eggs and that of irradiated miracidia were found to be radiation dose dependent and also decreased as the miracidia and miraciadia hatched from irradiated eggs were shortened, only 19% and 5% of those exposed to ultraviolet for 30 minutes survived for 3 hours as compared with 80% survival rate in control experiments. When miracidia were directly exposed to radiation, ineffectivity rate decesed with rising radiation dose while no significant difference was observed in ineffectivity of miracidia from irradiated eggs. The batches of S. mansoni cercariae exposed to various radiation dose and the control batch remained actively motile 30 minutes post-irradiation. Thereafter cercarial activity decreased with increasing radiation dose and cercarial age. There was no significant difference between the attachment rate of the batches of cercariae. The recovery rates (0.00-49.00%) of worms were significantly different from he rate of attachment of cercariae to the mice (93.50 - 100.00%). Maturation and penetration rates were dependent on radiation dose. Eggs deposited in the liver of mice and hatchability rate of the eggs varied significantly with the radiation dose. When radiation of cercariae at different levels in water and the reproductive potentials of the adult worms were studied, at a depth of 10.0cm the number of worms recovered was 25, while at 72.5cm the corresponding number of worms recovered increased to 52. Similarly, the pairing of worms, egg-load per gram of liver and hatchability of eggs increased as compared with control. When mice were infected with mixed radiated, and non-irradiated cercariae, the rate of intestinal adult worm recovery decreased form 52 to 0 as the proportion of irradiated cercariae increased. No effect on pairing was evident even when all cercateriae were radiated. Irridiation of cercariae did not influence the haemoglobin and packed cell volume of the host and their offsprings. There was an increase in the weight of infected mice which was more significant the more intense the radiation. Reproduction in female mice with irradiated cercarial infection were negligibly affected by the presence of irradiated schistosomes and could be ignored.
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Keywords
Ultraviolet Radiation , Schistosoma Mansoni
Citation
Ariyo, A.A, (1988), Studies on the Effects of Ultraviolet Radiation on Schistosoma Mansoni, University of Lagos School of Postgraduate Studies Phd Thesis and Dissertation Abstracts, 195pp.