Pyrethrins are a group of insecticides derived from the flowers of the chrysanthemum plant. They have been widely used in domestic and industrial applications since the 1800s. Pyrethrin is a common ingredient in poisons to kill jumping and flying insects, including bug bombs, aerosol sprays, and shampoos to treat fleas and lice.
Neurotoxic Effects
Pyrethrin has an effect on the central nervous system, and can cause changes in nerve and brain function. Symptoms of pyrethrin poisoning can last up to two days. Long-term, regular exposure can damage the central nervous system. Short-term skin exposure to large amounts of pyrethrin causes itching, numbness, and burning. Exposure to large amounts of pyrethrin by inhalation or eating traces left on food can cause nausea and headaches, as well as skin symptoms. Severe symptoms of pyrethrin poisoning include muscle twitching, convulsions, lethargy, and changes in awareness. Loss of consciousness is also possible.
Allergic Effects
Some people are allergic to pyrethrin, and may experience a reaction to any type of exposure. Mild symptoms such as sneezing, hives, and shortness of breath are possible, as well as more serious symptoms, such as severe asthmatic reactions, difficulty breathing, and heart failure.
Carcinogenic Effects
There is currently no clear evidence that pyrethrin causes cancer in either people or animals. However, the "Journal of Pesticide Reform" warns that pyrethrin caused thyroid tumors in laboratory in vitro tests. Farmers who regularly use pyrethrin pesticides in their fields may have an increased risk for leukemia.
Effects on Children
Pyrethrin's effects on children are similar to those for adults. The Agency for Toxic Substances and Diseases states that reactions are possible at lower doses of exposure because children's skin absorbs the chemical more easily. There is some evidence from animal studies that babies exposed to pyrethrin in utero may suffer damage to their immune systems. Animal studies also indicate the possibility of brain damage in young mammals.
Reproductive Effects
There is no clear evidence that pyrethrin causes reproductive damage. However, the "Journal of Pesticide Reform" cites an in vitro study which showed that pyrethrin disrupted normal functioning of human and animal sex hormones. The Extension Toxicology Network notes one study that showed pyrethrin exposure immediately prior to mating in rats led to decreased birth weight in the offspring. Pyrethrin has been found in the milk of cows exposed to the chemical.
Member Comments