Permethrins

Permethrins are synthetic chemicals belonging to the pyrethroid class of insecticides. They are derived from pyrethrins, natural insecticides found in chrysanthemum flowers. Permethrins are designed to be more stable and longer-lasting than natural pyrethrins, making them effective for a wider range of applications.

Their primary mode of action is by disrupting the nervous system of insects. Permethrins interfere with sodium channels in nerve cell membranes, causing them to remain open for extended periods. This leads to repetitive nerve firing, paralysis, and ultimately death of the insect. They are generally considered to have low toxicity to mammals, birds, and fish compared to their toxicity to insects.

Permethrins are widely used in agriculture to protect crops from insect pests, in public health for mosquito control to prevent the spread of diseases like malaria and West Nile virus, and in veterinary medicine to control fleas, ticks, and lice on animals. They are also found in consumer products such as insect repellents, household insecticides, and treated clothing.

In humans, exposure can occur through direct contact with permethrin-containing products or through environmental contamination. Symptoms of overexposure can include skin irritation, tingling or numbness, and in rare cases, neurological effects. However, when used according to label instructions, permethrins are generally considered safe for human use. Environmental concerns include potential harm to non-target insects, particularly aquatic invertebrates.