| dc.description.abstract | Previous studies have shown that the rat is
not a permissive host of Schistosoma mansoni. More
cercariae die in the skin of this host during penetration
than in the permissive laboratory hosts such as mice and
hamsters; the worms which grow in this host are usually
stunted; and they inhab:t the liver and produce relatively
few eggs which give rise to non-viable miracidia. Also
it has been observed that there is always a rapid drop in
the number of worms recovered by perfusion after the fourth
week of infection. However, there are still many gaps in
our knbwledge of the biology of this parasite in this
particular host.
In this study attempts were made: to trace the
route(s) of migration of the schistosome from the lungs
to the liver; to study its development; and to determine
the fate of the worms which apP?rently disappear
from the liver of this host after the fourth
week of infection.
Results of these investigations have
shown that: S, mansoni migrates from the lungs
to the liver mainly through the blood vascular
system; and that, a few parasites may migrate
through the pleural ti~ue, into the pleural
cavity, across the diaphragm, into the
peritoneal cavity, and thence into the liver;
but there was no evidence of the use of any
other route(s), The development of the parasite
in the rat ~s the same as that occuring ~n the
mouse (a permissive hostof the parasite) upto
around the twenty-eighth day, Thereafter
development, particularly that of the female
worms appears to be delayed, and is completed
around the forty-second day of development.
Most of the worms which appear to disappear
from the liver of this host, actually rema~n
trapped ~n blood vessels of the organ and
therefore can not be recovered by perfusiono
He re they induce a leucocytic inflammatory
reaction, involving mainly eosinophils,
macrophages and lymphocytes, which eventually
destroys them. A few of the "disappearing",
worms are carried in the ~loodstream to other
parts of the body such as the heart and | en |
