RAYMOND -- Outdoor activities in the summer increase the risk of exposure to poison ivy, but the plant's danger does not disappear with the hot temperatures.

Thriving on Mississippi's hot, humid climate, poison ivy is very common in the state and causes discomfort for 80 to 85 percent of the population.

Norman Winter, extension horticulture specialist in Raymond, said poison ivy and poison oak have similar three-leaf patterns and should not be confused with the five-leaf Virginia creeper. Poison oak is the least common of the plants and rarely found in the state.

"Poison ivy is spread mainly by birds who feed on its clusters of white berries, which are present in late summer and early fall," Winter said. "Poison ivy can be found as either a shrub or a vine."

The horticulturist said in most cases a person must come in contact with the plant. Occasionally, the poison may be transmitted from a pet who has been exposed or from clothing that has touched the plants. Reaction to the plants will occur 12 to 48 hours after contact.

For those who are extremely sensitive, pollen under normal conditions or oil in the air from burning plants may cause an adverse reaction. Therefore, burning is not recommended for eliminating the plant.

Winter recommended the use of herbicides for removing the plants. More than one application may be required to ensure thorough removal. Use caution when removing dead plants after spraying with herbicides.

"The liquid blisters on the skin that result in serious cases will not spread the poison," Winter said. "The primary concern is for secondary infections resulting from the blisters."

If exposure or the possibility of exposure occurs, avoid touching sensitive parts of the body with unwashed hands. Eyelids are especially sensitive. The least susceptible areas are the palms, scalp and the soles of the feet.

Use caution in seasons other than summer when the plants may not be easy to distinguish. Because of its bright colorful leaves, many people mistakenly cut the plant for ornamental reasons in the fall. In the winter, when no leaves are present, reactions may be caused by breaking roots or plant stems.

Consult with a physician whenever the rash covers more than 5 percent of the body or if infection is occurring, said Linda Patterson, extension health specialist at Mississippi State University. If blisters have a yellowish rather than clear discharge, professional medical attention is necessary.

Patterson said the length of time the poison ivy remains on the skin before it is washed off will effect the severity of the rash and the time before the rash appears. For this reason, the rash may wrongly appear to spread from scratching.

After exposure to the plants, Patterson suggested washing the skin with very soapy water without scrubbing hard. Diluting the poison with soapy water or rubbing alcohol can reduce the infection.

Patterson suggested patients take Benadryl tablets and/or apply 1 percent hydrocortisone lotions or cream. Both medications will reduce itching and stop the allergic reaction.