Pithomyces chartarum- ‘Stellenbosch photosensitivity
By Dr Mackie Hobson BSc(Agric),BVSc

1. Poisoning

The fungus Pithomyces chartarum can cause hepatogenous photosensitivity. Not all animals in the flock will show photosensitivity.

Under what conditions does poisoning occur?

Varies from cool coastal regions to hot arid karoo. The condition has occurred in sheep on ryegrass and clover pastures.

The fungus grows on dead plant material in the pasture and produce conidia (spores). These spores contain the hepatotoxic substance. The spores contaminate the pasture.

How long before photosensitivity occurs?

10-14 days with range 9 to 24 days

What is seen on Post Mortem?

• Yellow-brown mottles appearance of liver
• Lobulated in chronic cases
• Thickened bile ducts
• Oedema and ulceration of gall bladder and urinary bladder may occur
• Kidney is swollen and yellow brown in colour

Reference:
Plant poisonings and mycotoxicoses of livestock in southern Africa, Kellerman, Coetzee, Naude