Did you know that Karaka Berries are highly toxic for dogs?
The New Zealand native evergreen Karaka tree (Corynocarpus laevigatus) is a common sight in coastal regions, particularly in the North Island. Each year during the Summer to Autumn months it produces a fleshy orange berry which can be highly toxic to our canine companions. Karaka trees are more common than you may think and are found frequently in backyards and parks, hence being able to recognise them is essential for dog owners.
The Karaka tree is a large tree than can grow up to 15 metres tall. They can be identified by their dark glossy leaves, and when in season, produce characteristic orange, olive shaped fruit.
The principal toxin, commonly called Karakin (a glucose ester of 3 nitropropionic acid) is found in highest concentrations in the fruit and enclosed seeds.
The pathophysiology of Karakin toxicity is complex; it causes oxidative stress, inhibits normal energy (ATP) production in the mitochondria of the cell and causes excessively high neurotransmitter levels resulting in neuron cell death.
Fruit remains toxic for several months, hence toxicity can occur even after the fruiting season has ended.
Karakin acts as a potent neurotoxin when ingested and can cause convulsions, spasms, hindlimb paralysis, incoordination and death.
Karaka toxicity affects not only dogs; cases have also been seen in livestock, the native Kiwi bird and has even been reported in Honey Bees feeding on the trees nectar.
Its critical given the highly toxic nature of these fruits that all dog owners familiarise themselves with the leaves and fruit and are able to identify any dangers of these trees on their walks.
There are many tree identification resources available online, and a quick google for ‘Karaka trees’ will display a range of images that will help you to identify the potential dangers on your routes.
What to do if you think your dog has eaten Karaka Berries
Ingestion of any number of Karaka berries should be treated immediately by your local vet or an emergency vet; decontamination (inducing vomiting) is the most effective way to avoid toxicity. Induction of vomiting should never be attempted at home; most of the commonly suggested home remedies can have dangerous side effects and complications such as aspiration.
Should your dog present with clinical signs of Karaka toxicity, which can often be delayed up to 48 hours after ingestion, decontamination is no longer an option. Treatment of clinical disease is symptomatic as there is no specific antidote for Karakin. Supportive care will generally include intravenous fluids, anti-nausea medication and anticonvulsants in case of seizures. Despite aggressive therapy, some cases may still lead to death if damage to the central nervous system is severe.
Affected dogs will typically remain in hospital for several days before discharge can be considered.
Awareness is our greatest preventative for this tragic toxicity. All dog owners should familiarise themselves with the Karaka’s appearance and be on the look out for fruiting trees during January to April.
Chronic scavengers should be watched closely on walks and be kept on a lead around identified trees. Training dogs to wear a basket muzzle, which prevents the dog from eating, during walks may be necessary for the repeat offender. Unfortunately despite the unpleasant experience of being made to vomit after eating something they shouldn’t, most dogs never learn!
You can read more about the Karaka Tree and view images on the New Zealand Plant Conservation Network Karaka Page