PARASITE MIGRATION AND HOST REACTION IN MICE EXPOSED TO IRRADIATED CERCARIAE OF SCHISTOSOMA MANSONI
Investigations were undertaken to ascertain: what host organs are reached by Schistosoma cercariae gamma irradiated at different dose levels; the nature and extent of lesions produced in these host organs; and possible similarities existing between the tissue reactions to irradiated cercariae and those observed previously in natural and acquired resistance. Cercariae were exposed to 2500, 5000, and 50,000 rep doses of Co/sup 60/ gamma radiation and immediately injected into mice, the tissues of which were examined for schistosomula 50 days later. Irradiation interfered with the ability of schistosomes to reach maturity in mice. Since the death and disintegration of schistosomula stimulated a considerable degree of inflammation, different dosage levels provided contrasting tissue reactions. At 50,000 rep, cercarial dermatitis wvith ulceration and marked vasculitis was the main pathologic feature; at 5000 rep numerous granulonnatous foci were seen in the lung; and at 2500 rep foci of liver cell necrosis and liver granulomata occurred. Irradiation of 2500 rep appeared to be the best dose since the less heavy concentration of parasites in a single organ produced the least amount of objectionable pathologic changes. The findings confirm that the life span, maturation, and migration of irradiated cercariae are affected in proportion to the irradiation level. No eggs were produced at any of the radiation levels studied. Stunted young adults developed from cercariae irradiated at 2500 rep. These attained their greatest number 40 days after exposure, but by day 50 most of the schistosomula had died, leaving small granulomas and calcified foci as a residue. When cercariae were exposed at 5000 rep, only a few sporadic stunted worms were found in the liver, and with 50,000 rep, most of the schistosomula died in the skin injection site. However, variations of biological vigor were such that even at 50,000 rep some parasites were able to migrate from the skin to the lungs and reach the liver, as shown by onc granuloma observed in that organ. (BBB)
- Research Organization:
- Harvard Medical School, Boston
- NSA Number:
- NSA-18-004986
- OSTI ID:
- 4146390
- Journal Information:
- Exptl. Parasitol., Vol. Vol: 13; Other Information: Orig. Receipt Date: 31-DEC-64
- Country of Publication:
- Country unknown/Code not available
- Language:
- English
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