White snakeroot
General poisoning notes:
White snakeroot (Eupatorium
rugosum) is a native herb that grows in rich soils in eastern Canada. This
plant has caused illness and death of humans and several types of livestock.
Large losses of human life occurred in the 19th century from the mysterious
milk sickness. Mortality ranged from 10 to 25%, and the population of entire
villages left a location because they could not find the cause of the disease.
It was later discovered that cattle had ingested white snakeroot and that a
toxin was subsequently passed through the milk to humans and was toxic. With
modern collection and combination techniques, milk sickness from commercial
milk sources is no longer a problem. However, the resurgence of small-scale
farming and home milk production may result in occasional cases of milk
sickness (Kingsbury 1964, Stotts 1984, Cheeke and Schull 1985, Beier and Norman
1990).
Several
types of herbivorous livestock have also been poisoned by ingesting white
snakeroot, resulting in a disease called trembles. Cattle, goats, horses,
sheep, and swine have shown toxic reactions. Suckling animals can develop milk
sickness as well. Trembles was more of a problem in the past, before the increased
use of herbicides and prepared feeds. Poisoning was also more frequent when
animals were allowed to range through bushlots. The amount of white snakeroot
that must be ingested before death is variable, ranging from 1 to 20%. Symptoms
can occur within a few days or up to 3 weeks later. Daily intake rates of
0.5-1.5% of body weight generally leads to the onset of symptoms. Drying the
plant material does not completely remove the danger to animals (Doyle and
Walkley 1949, Kingsbury 1964, Cheeke and Schull 1985, Beier and Norman 1990).
Additional
care must be taken with milk from cattle or goats that may have ingested white
snakeroot. Many articles state that a lactating animal does not always show
symptoms. However, milk from that animal can still cause milk sickness. Calves,
humans, and cats have been poisoned in such cases. Dogs given the milk are also
be at risk. Experimental work has shown that trembles can occur in rabbits and
guinea pigs. White snakeroot grows in rich moist open woods and along water courses.
Animals should not be allowed to graze this plant.
Description:
Plant: erect,
perennial, 1'-5' tall forb with 1 to 3 mostly hairless, leafy stems Flower: head with
12-25 white disk flowers; inflorescence 3" flat to roundish,
branched clusters of many heads; blooms July-Oct. Fruit:dry seed on
fluffy pappus Leaf:opposite, blade 1 1/2 to 5 times longer than the long
stalk, bases rounded, edges coarsely toothed.
Nomenclature:
Scientific Name: Eupatorium rugosum Houtt.
Synonyms: incl. Eupatorium rugosum
Houtt. var. rugosum f. villicaule Fernald, var. tomentellum (B.L. Rob.) S.F.
Blake; Ageratina altissima (L.) R.M. King & H. Rob., incl. var. angustatum
(A. Gray) S.F. Blake
Vernacular
name(s): white snakeroot
Scientific family
name: Compositae
Vernacular family
name: composite
Geographic Information:
New Brunswick, Ontario,
Nova Scotia, Prince Edward Island, Quebec.
Toxic parts:
Stems, leaves.
Notes on Toxic plant chemicals:
Tremotol is a
secondary aromatic alcohol with a sterol and ketone fraction. One of these
ketones, tremetone, has been tested on chickens, with negative results, but was
toxic to goldfish in experimental studies. In Iowa the concentration of
tremotol was found to be highest during the summer (Kaufmann 1982).
Toxic plant chemicals:
Tremetol.
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:
Appetite,
loss of, ataxia, brain, congestion of, breathing, rapid, coma, constipation, death,
depression, gait, unsteady, lungs, congestion of, nasal discharge, nausea, recumbency,
prostration, trembling, urine, yellowish, weakness, vomiting.
Dogs
Goats
Horses
General symptoms of
poisoning:
Breathing,
labored, breathing, rapid, breathing, shallow, constipation, death, depression,
gait, rigid, lungs, congestion of, nasal discharge, pupil dilation, sweating, recumbency,
trembling, prostration.
Humans
Rabbits
Sheep
General symptoms of
poisoning:
Acidosis, death, nervousness,
trembling.
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