Facial Eczema (FE) is a disease of the liver caused by a mycotoxin (sporidesmin) that affects all ruminants even when they have low exposure to the fungus (Pithomyces Chartarum) which grows on dead and dying pasture litter when moisture and temperatures are favourable for spore growth.
Sporidesmin attacks the cells in the bile duct which impairs the liver’s capacity to detoxify and excrete waste products. One of these, phylloerythrin, a breakdown product of the green pigment in plants, chlorophyll, accumulates in various body tissues, including skin, making the animal sensitive to sunlight. UV radiation then causes immediate and extremely intense sunburn in poorly or non-pigmented parts of the body. The destructive effects on the bile ducts and liver cells will cause death as a result of liver failure. Fortunately, at low levels of FE challenge, most affected animals will survive and recover thanks to the liver’s enormous potential for repair and regeneration, but production will be seriously reduced in the short term.
Pithomyces Chartarum spores grow quickly in dead or dying grass litter typically found in the base of pasture during summer and autumn months when conditions are more favourable for spore development. This is usually towards the end of January or early February, but especially when the nights become warm and humid (>12°C), or a dry period is followed by rain. However, a slow build-up of spores and continual exposure over a period of time will also result in similar risk levels.