Death camas-Zigadenus venenosus S. Wats.-Poisonous plant

Death camas

General poisoning notes:

Death camas (Zigadenus venenosus) is a native perennial herb that is found from British Columbia to southwestern Saskatchewan. The plant is one of the most toxic springtime plants, especially to sheep. Cattle and horses are also occasionally poisoned. Swine vomit the plant so readily that no natural cases of poisoning have been reported. Poultry may also be poisoned, although there are no reported cases. Honey bees are poisoned by the nectar and pollen (Kingsbury 1964, Barker 1978; Panter and James 1989). Humans have also been poisoned after ingesting the bulbs, which were mistaken for other plants such as onions (Allium spp.) or camas (Camassia quamash). Ingesting the flowers and flower buds has caused poisoning in children (Cameron 1952, Spoerke and Spoerke 1979). These plants should be considered poisonous to all livestock and humans.

Nomenclature:

Scientific Name: Zigadenus venenosus S. Wats.

Vernacular name(s): death camas

Scientific family name: Liliaceae

Vernacular family name: lily

Geographic Information

Alberta, British Columbia, Saskatchewan.

Notes on Poisonous plant parts:

All parts of death camas contain toxic alkaloids, with the bulbs containing the most. The bulbs may be pulled up by animals when the ground is wet or may be ingested by humans who mistake them for other plants, such as onions. The nectar and pollen are poisonous to bees. Most cases of animal poisoning occur in spring, when other forage is not plentiful (Kingsbury 1964, Barker 1978).

Toxic parts:

All parts, bulbs, flowers, leaves, pollen.

Notes on Toxic plant chemicals:

Steroidal alkaloids, including zygacine, have been found in these plants. Death camas is considered to be the most toxic members of the genus Zigadenus. The average minimum lethal dose in sheep is estimated to be equal to ingesting 0.6-2.0% of an animal''s body weight in plant material (Kingsbury 1964).

Toxic plant chemicals:

zygacine

Chemical diagram(s) are courtesy of Ruth McDiarmid, Biochemistry Technician, Kamloops Range Station, Agriculture and Agri-Food Canada, Kamploops, British Columbia, Canada.

Animals/Human Poisoning:

Note: When an animal is listed without additional information, the literature (as of 1993) contained no detailed explanation.

Cattle

General symptoms of poisoning:

Ataxia, death, dyspnea, nausea, prostration, salivation, trembling.

Notes on poisoning:

Cattle are occasionally poisoned by death camas. Symptoms are very similar to those for other livestock. Salivation is sometimes less and nausea greater than in sheep. Other symptoms include muscular weakness, ataxia, trembling, prostration, and death. The heart action becomes weakened (Kingsbury 1964).

Honey bees

General symptoms of poisoning:

Death.

Notes on poisoning:

In field cases, adult bees died after foraging on this plant. In experiments, both the nectar and pollen, collected by centrifugation, poisoned the bees. The plants bloom for only a couple of weeks and secrete little nectar. Solitary native bees seem less affected by the toxins (Barker 1978).

Horses

General symptoms of poisoning:

Colic, depression, diarrhea, salivation.

Notes on poisoning:

Horses have been poisoned after ingesting hay containing immature seed pods of death camas. The symptoms of illness included colic, salivation, cramping, depression, and intermittent diarrhea (Fuller and McClintock 1986).

Humans

General symptoms of poisoning:

Blood pressure, low, breathing, shallow, coma, death, diarrhea, drowsiness, pupil dilation, vomiting.

Notes on poisoning:

Humans have been poisoned after ingesting the bulbs and flowers. In most cases, the bulbs are mistaken for onions. A 2-year-old child became ill after eating the blossoms. Symptoms of poisoning include vomiting, slow breathing, unconsciousness (though responsive to pain or movement), hyperactive tendons and limbs, pupil dilation, and hypotension. The alkaloids cause local irritation when ingested and affect the cardiovascular system by slowing the heart and decreasing blood pressure. Treatment includes emesis, activated charcoal, and saline cathartic. Atropine was also given (Cameron 1952, Spoerke and Spoerke 1979).

Poultry

General symptoms of poisoning:

Coma, death, diarrhea, incoordination, prostration.

Notes on poisoning:

In one case (with an related species of Zigadenus), poultry were poisoned. Symptoms included diarrhea, staggering gait, incoordination, prostration, and coma. Many birds died (Kingsbury 1964). Death camas can also poison poultry if they ingest the tender shoots.

Sheep

General symptoms of poisoning:

Breathing, shallow, cyanosis, death, mouth, frothing of, muscle, weakness of, nasal, discharge, prostration, salivation, urination, frequent, vomiting.

Notes on poisoning:

Death camas is considered to be one of the most toxic plants on the western rangelands, and ingestion causes greater loss of life of sheep than any other plant in springtime. Symptoms include excessive salivation, nausea, frothing at the nose and mouth, vomiting, increased urination and defecation, muscular weakness, ataxia, prostration, and death resulting from heart failure. Postmortem examination shows the heart in complete diastole. Coma may occur for a few hours to several days before death. Lesions include severe pulmonary congestion, edema, and hemorrhage. Losses occur most frequently in the spring, when other forage is not plentiful (Long 1981, Panter and James 1989).

Swine

General symptoms of poisoning:

Diarrhea, vomiting.

Notes on poisoning:

Experiments show that swine are susceptible to the poisons, but cases of poisoning are not encountered under natural conditions because swine readily expel the material by vomiting (Kingsbury 1964).