Shannon Fox, age 14, of Dayton, Ohio, for her question:
WHAT MAKES POISON IVY DANGEROUS?
Poison ivy is the common name for several kinds of harmful shrubs and vines related to the sumac. Poison ivy grows in almost all parts of the United States and southern Canada. It is dangerous because of a poisonous oil somewhat like carbolic acid.
In the Southern states and on the Pacific Coast, the bush form is found more than the vine. Poison oak is another name for a dangerous plant that grows in bush form. Like poison ivy, poison oak has leaves composed of three leaflets.
The tissues of all the poison ivy varieties contain an oil that is extremely irritating to the skin. It may be brushed onto the clothing or skin of persons coming in contact with the plants. Many people have been poisoned merely by taking off their shoes after walking through poison ivy.
People can get poisoned from other people, but only if the oil remains on their skin. The eruptions themselves are not a source of infection.
Because poison ivy is very common, everyone who goes into the fields or woods should learn to recognize it. In spring, the three leaflets on the bushes and vines turn to shiny green. They turn red or orange in autumn.
Small greenish flowers grow in bunches attached to the main stem close to the point where each leaf joins it. Later in the season clusters of poisonous, berrylike drupes form. They are a dirty yellowish white, with a waxy look like the berries of mistletoe.
The plants can be destroyed by uprooting them or by spraying them with plant killing chemicals. But poison ivy and poison oak are so common that such methods have not been very effective. Avoiding contact with the plants is the best method to follow if you don't want to suffer the discomfort contact with the plants can cause.
If you have touched poison ivy, it is best to immediately wash thoroughly with soap and water.
Washing quickly after touching a poison ivy plant is good because it usually takes some time for the oil to penetrate the skin and do its damage. Also, care should be taken not to touch the face or any other part of the body, for even tiny amounts of the oil will cause irritation.
If poisoning develops, the itching reddened skin and blisters may be treated with soothing dressings of calamine lotion, Epsom salts or bicarbonate of soda.
Scientists have developed a vaccine that can be injected or taken by the mouth. However, this is effective only if taken before exposure.
Several species of poison ivy and poison oak belong to the cashew family.
Each poison ivy and poison oak leaf is made up of three leaflets which are notched at the edges. Two of the leaflets form a pair on opposite sides of the stalk, while the third leaflet stands by itself at the tip of the leaf.