Turning a Leaf

A poison ivy vaccine is near

Fire fighters battling brushfires in Southern California's Los Padres National Forest have long had to cope with an occupational hazard beyond that of smoke and flames: poison oak, the Western cousin of poison ivy. Not only do they risk coming into contact with the vine, but they also breathe in fumes from its burning leaves, often resulting in infections of the eyes, throat and lungs, as well as rashes and itching skin. "It's almost everywhere," says Forest Service Researcher Jerry Oltman. "It's a real problem."

Every year Americans from gardeners to hikers groan and curse at the effects of poison ivy. As much as 25% of the population is so sensitive to the weed that contact can result in high fever and oozing blisters. Lotions are generally ineffective, and steroids, prescribed for the most severe cases, can produce a serious drug reaction. But help is at hand. A flurry of scientific advances promises to take the sting out of one of North America's most irritating environmental hazards:

> An experimental vaccine, in pill form, offering real hope for permanent protection has passed its preliminary tests at the University of California at San Francisco and seems headed for Food and Drug Administration approval within two years.

> More immediately, the Forest Service is testing a method for quickly showing if a person is sensitive to the poison ivy family. In the test, also developed at U.C.S.F., a small drop of the plant's poisonous chemical, urushiol, is placed on the arm, and the reaction is monitored.

> For those shown to be sensitive to the plant, scientists at the Oregon Health Sciences University in Portland have developed a cream that can be applied daily and that prevents the toxin from reaching the skin. To shield fire fighters from the plant's toxic smoke, the researchers are also developing a specially treated material that can be fashioned into protective clothing and masks.

Scientists have long understood how to make vaccines from urushiol. But what protection these drugs provided was accompanied by an excruciating side effect: anal itching. Last year, researchers found a way to neutralize the urushiol molecules that cause the itching. Dr. William Epstein, who heads the U.C.S.F. research team, told a meeting of dermatologists in Toronto last week that the new vaccine could be on the market in time for the 1986 poison ivy season.