Disease Biology
In the United Kingdom, F. hepatica is a frequent cause of disease in ruminants, most commonly between March and December. Cattle and sheep are infected when they consume the infectious stage of the parasite from low-lying, marshy pasture. The effects of liver flukes are referred to as fascioliasis, and include anaemia, weight loss and submandibular oedema; diarrhoea is only an occasional consequence. Liver fluke infestation is diagnosed by yellow-brown eggs in the faeces. They are not distinguishable from the eggs of Fascioloides magna, although the eggs of F. magna are very rarely passed in sheep, goats or cattle.
A serious consequence of the liver damage caused by fascioliasis is that latent Clostridium novyi spores can be activated by the low oxygen conditions in the damaged tracts the parasite forms in the liver; this can lead to "black disease", caused by Clostridium novyi type B or immune-mediated haemolytic anaemia (IMHA) leading to haemoglobinuria caused by C. novyi type D.
Read more about this topic: Fasciola Hepatica
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