Infection by liver flukes

Infection by liver fluke, a type of flatworm, is a widespread parasitic disease present on all continents. Also known as fascioliasis, it affects the liver and bile ducts of a large variety of warm-blooded animals, domestic and wild, and humans, causing enlargement and thickening of the walls of the bile ducts and fibrosis of the liver tissue, resulting in loss of condition, digestive disorders, anaemia and other symptoms of parasitism. In sheep, extensive liver damage caused by flukes contributes directly to 'black disease', (infectious necrotic hepatitis), which does not occur in healthy animals. Economic losses arise from emaciation of domestic animals, and from production of liver unfit for human consumption.

Liver flukes are hermaphroditic and release their eggs into the bile ducts of the host, which are then passed out through the faeces. There are many species of liver flukes and since all need intermediate hosts, it is hard to develop control measures which apply to all. In the three most common species, the eggs embryonate when they reach water, where they hatch in two to six weeks and find suitable snails (intermediate hosts) in which to mature. Transmission comes via the snails, from which the fluke larvae are deposited on grass or other vegetation or under the surface of the water, and are then ingested by the host animals. Carnivores or man may become infected from eating the livers of diseased animals, or from drinking contaminated water intake.

Four common species are: the common liver fluke Fasciola hepatica, large American liver fluke Fascioloides magna, giant liver fluke Fasciola gigantica, and lancet fluke Dicrocoelium dendriticum. The lancet fluke differs from the other three in so far as the eggs are eaten by land snails in which they mature into cercariae which escape from the snails and are eaten by ants. The ants in turn are eaten by cattle and other host animals while grazing. Adult flukes have a long life cycle inside the infected animal.

Treatment of fascioliasis required high or drug multiple doses often with unpleasant side-effects. Recently, products derived from myrrh, from the tree Commophora molmol , and various other species of Commiphora, are becoming recognized as possessing significant antiseptic, anaesthetic, anti-parasitic and anti-tumour properties and appear to offer a natural (and ancient) remedy.

Fascioliasis was known in ancient Egypt since remote times; fasciola eggs (liver fluke) have been detected in a mummy. At the height of the Roman Empire, Dhofar (Oman) was exporting immense quantities of frankincense, myrrh and other oils, by ship to Yemen and thence up the Red Sea, and by camel caravan overland to Petra and the Mediterranean. Myrrh is still harvested in Oman

Liver flukes infect over 17 million people worldwide causing marked morbidity and mortality.