On April 28, a stoical, experienced 60 year old hunter, was on a three day trip deerstalking with two friends in the Kaweka Ranges on the southern side of the remote Mangatainoka River. They were to be collected by helicopter at a prearranged time, and carried no means of emergency communication.
At around 9am while descending into a small clearing, he slipped on wet grass, and fell into a tree nettle known as ongaonga, Urtica ferox. He was scratched about the legs, face and hands. Within the first 15–20 minutes he began to experience severe abdominal cramps, and thereafter a terrible burning sensation in his feet, and visual blurring.
By the time he reached camp at 10.30am, he was weak, confused and pale, sweating profusely, salivating, and beginning to struggle for breath. His companions report his ability to hold a cup was grossly impaired by shaking. He was writhing in agony from cramps. He became hypothermic despite multiple layers of woollen clothing, a mountain-down sleeping bag, and fires being lit in an attempt to warm him. He was unable to speak clearly, but denied hallucinations or loss of consciousness. He did not sleep until midnight, when he began to feel a little warmer.
Before dawn he attempted to leave the tent to pass urine, but was unable to stand or control his lower limbs, falling repeatedly. His companions came to his rescue, and replaced him in his bag. He was now freezing cold after exposure to the -5 ̊ C temperatures, and again experienced extreme difficulty breathing.
Twenty-four hours after the encounter with Urtica ferox he was able to walk stifflegged around the clearing with the assistance of his friends. The helicopter arrived in the afternoon and he returned home late that evening.
On presentation the next day, his gait remained stiff, and he complained of residual tingling in fingers and tongue, muscular stiffness and soreness in his shoulders and limbs, and a foul taste in association with some flavours. He was orientated and appropriate in behaviour, and able to give a good account of events. Examination revealed increased muscle tone in lower limbs, and grip strength bilaterally reduced, but little else of note.
Thus was a severe response to the well documented but poorly publicised poisonous tree nettle, which has claimed at least one human and many animal lives in the past. The National Poison Centre was able to provide good information regarding the components of the sting which include histamine, 5-hydroxytryptamine and acetylcholine, and other substances not yet identified. An anaphylaxis kit has been prepared and its use taught to the patient and one of his companions.
It is my concern that noncareer hunter, fishers and trampers, as well as many tourists now exploring our reputedly ‘benign’ bush may be unwittingly at risk from this plant’s unpleasant and potentially fatal effects. It is found over a wide geographical area throughout the North Island and west of the main divide in the South Island, between sea level and 600m growing on the fringes of forested areas, in scrublands, and frequently forming thickets with individual specimens reaching 3m high. Resource material is listed below, providing drawings, photographs and clear identifying information,
Auckland Faye P. Clark