Claviceps purpurea (claviceps,
rye ergot). A mould belonging to the CLAVICEPTA family. Parasitic fungus growing
on rye, oats, other cereals and various grasses. Produces a mass of hyphae protected
by a hard, black coat (sclerotia), eventually taking the place of a grain on the
head of the cereal; exudes an unpleasant odour. On ripening and harvesting, the ergot
detaches itself from the spikelets of grains and becomes mixed in with the healthy
seeds or falls to the ground.
Animals most affected
Cattle, (sheep, goats, pigs, poultry and fowl).
Livestock fed contaminated grain, seed or fodder containing infected forage crops
or grasses. Today poisoning by ergot is considered to be rare due to improved modern
treatment of cereals with fungicides has greatly reduced the frequency and significance
of the parasite;
ingestion needs to be prolonged (over several weeks) before chronic ergotism
However, cereals contaminated with ergot are still to be found in 25-40% of crops,
notably after a period of drought.
Contains a number of alkaloids, all derivatives of lysergic acid: ergotamine, ergotoxine
(which is composed of a mixture of alkaloids), ergometrine (ergonovine or ergobasine)
with vasoconstrictive, sympathomimetic and oxytocic effects; amines and other nitrogenous
compounds.death through paralysis of the respiratory centres.
Oral doses are not well documented, g contaminated feed by mouth:
11 000 over a period of 2 months
100/day for 11 days
Clinical features Acute form
lethargy, shaking, stupor, blindness; insecticide available commercially
clonic convulsions, then CNS depression
death through paralysis of the respiratory centres.
diarrhoea, weakness, drowsiness, lameness;
stiffness and swelling of the lower joints of legs, coldness and loss of sensitivity
of the extremities, paraesthia;
development of necrosis and dry gangrene in distal parts (feet, muzzle, ear and
tail of animals; comb, tongue or wattles of birds), with distinct demarcation
between healthy and gangrenous tissues;
occasionally abortion, foetal death and sterility.
There is no specific treatment and no antidote for ergot poisoning:
for acute poisoning: symptomatic care only;
for chronic ergotism: no treatment advised;
avoid feeding ergot-ridden fodder (where the ergot-level is > 10%) to livestock
over a prolonged period;
remove animals from the source of infected grass, and ensure rest.