Poison ivy
General poisoning notes:
Poison ivy (Rhus
radicans; synonym Toxicodendron radicans) is a native shrub or
vine found throughout southern Canada. Three recognized varieties are found in
various parts of the country (Mulligan and Junkins 1977). Urushiol is the
allergenic agent found in most parts of the plant. Damage to plant tissues
causes the nonvolatile chemicals to be exposed. Humans are often sensitized,
with symptoms ranging from mild itchiness and redness to severe oozing lesions
with fever. Poison ivy is probably responsible for more cases of plant
dermatitis in Canada than any other plant. Urushiol can contaminate clothes,
tools, and the fur of domestic animals. Humans can subsequently develop
dermatitis from contact. Humans do not contract the dermatitis on first
contact, but most people are sensitized the first time (Mulligan 1990, Schwartz
and Downham 1981, Gayer and Burnett 1988).
Nomenclature:
Scientific Name: Rhus radicans L.
Vernacular
name(s): poison ivy
Scientific family
name: Anacardiaceae
Vernacular family
name: cashew
Geographic Information
Alberta, British
Columbia, Manitoba, New Brunswick, Nova Scotia, Ontario, Prince Edward Island, Quebec,
Saskatchewan.
Toxic parts:
All parts, leaves,
plant juices.
Notes on Toxic plant chemicals:
Urushiol, a group
of alkylcatechols, is found in the sap of poison-ivy plants. The allergic
reaction has been traditionally thought to involve initial oxidation by which a
protein-reactive quinone is formed. Recent work indicates that redox cycling in
the skin, following penetration of the allergenic alkybenzenes, initially
depletes local levels of endogenous-reducing equivalents such as NADH and
glutathione. Further cycling results in the uncontrolled generation of radical
species that exhibit protein reactivity. The urushiol is not volatile and can
contaminate clothing, tools, and domestic animals. Under dry conditions, the
chemical can remain harmful for long periods (Mulligan 1990,Schmidt et al.
1990).
Toxic plant chemicals:
Urushiol oil, 3-pentadecyl
catechol.
Animals/Human Poisoning:
Note: When an
animal is listed without additional information, the literature (as of 1993)
contained no detailed explanation.
Humans
General symptoms of
poisoning:
Blistering
blisters,
weeping
erythema
face,
edema of
itchiness
pneumonitis
temperature,
elevated
tracheitis.
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