THE VARIED ROLES OF SNAILS - National Universities Commission

(known as the lancet fluke). This fluke is a
very common biliary parasite of sheep and
other herbivores and accidentally infects Man
in Japan and China, Europe, N. Africa far
East and Northern Asia.
Eggs passed in faeces are ingested by land
snails Limicolaria Cercariae appear in slime
balls secreted by the snails and are eaten by
ants of the genus Formica in which the
metacercariae develop.
Infection occurs when the hosts accidentally
eat the ants while feeding. Spurious
infections have occurred in persons who ate
infected sheep liver and can pass eggs in
faeces for about a week or several days.
(ii) Eurytrema pancreaticum, is a related fluke
and is commonly present in the pancreas, is a
related fluke and is commonly present in the
pancreatic duct of cattle, sheep and monkeys.
Occasional human infection has been noticed
in China and Japan.
(iii) Intestinal Flukes:
A number of fluke parasites parasitize the
human intestine. These include Heterophyes,
Metagonimus, Wastonium and Echinostoma.
Only one fluke Gastrodiscoides hominis
parasitizes the human large intestine.
The snail intermediate hosts for these are
presented in table 7.
86