PATERSON’S CURSE

PATERSON’S CURSE

Echium plantagineum, commonly known as Paterson’s curse, is an invasive winter annual herb. It can be identified by its deep purple spring blossoms, which can cover broad fields of agricultural land. Paterson’s curse was introduced to Australia in the 1850’s and can now be found in all states and territories of Australia. The most significant growth occurs in pastoral regions of NSW, VIC, SA and the south-west region of WA. Whilst Paterson’s curse is more commonly found in areas with greater winter rainfall, its tolerance of different climates and soil conditions allows it to grow almost everywhere in Australia.

Paterson’s curse is poisonous to all grazing animals, with horses and pigs being most susceptible to the toxic effects. The main toxins of concern in the plant are known as pyrrolizidine alkaloids. Unlike other livestock, horses and pigs do not have the necessary micro-organisms in their stomach to break down these alkaloids. As a result, following repeated ingestion over weeks to months these toxins can accumulate in the body and result in poisoning. Whilst the toxin accumulates, animals can remain well and this can make the diagnosis of poisoning from Paterson’s curse challenging.

Horses affected by this plant may experience loss of appetite, persistent diarrhoea, dullness, aimless walking, persistent yawning, muscle tremors and potentially blindness. In severe poisoning, horses can develop liver injury which often results in death by the time the illness becomes apparent. Although pigs are known to be highly susceptible to the toxic effects of Paterson’s curse, poisoning is rarely reported in this species due to limited access to the plant. Once established, eradication of Paterson’s curse can be extremely difficult. This makes prevention of further spread a high priority. Animal owners requiring more information about the control of Paterson’s curse can contact their state or territory agricultural department (or equivalent).

The Animal Poisons Helpline provides free advice to pet owners in Australia and New Zealand and can be reached on 1300 869 738 (AU) or 0800 869 738 (NZ). If you don’t already follow the Animal Poisons Helpline Facebook page, follow now to receive live animal poisons alerts and updates. If you are a member of a veterinary team in Australia or New Zealand, you can join the Animal Poisons Centre For Vets Facebook group which is regularly updated with toxicology tidbits and poisoning trends. We thank the Western Australian Department of Primary Industries and Regional Development for supporting this post.