Eggs of these parasites get into freshwater via human or animal faeces and are ingested by certain snails. Inside these snails the eggs are hatched, producing a large number of larvae which will leave the snail and swim around in the water until they see a chance to penetrate a fish. Humans will get infected after eating the fish. The larvae will make their way to the bile where they mature and reside the rest of their life, shedding eggs. A less common way to get infected, is swimming in rivers full of the larvae of the flukes.
Symptoms vary with the amount of flukes that get into the body.
Chronic symptoms include feeling weak, diarrhoea and jaundice. Don't swim in waters of regions where the worms pose a threat. The disease is rarely fatal. Although correct to the best of my belief, these pages should be used as a source of information only, not as a substitute for seeking competent medical advice. I can accept no responsibility whatsoever for errors which may damage health or cause any other problems.