How2Day: What Are the Dangers of Spraying Insecticides to Kill Ticks?

Ticks are blood-sucking parasites that feed on warm-blooded mammals, including humans. There are over 800 species of ticks worldwide. Many people choose to treat their yard for ticks to prevent them from attaching to pets or feeding on family members, but chemical pesticides come with their own significant risks. Some of the most commonly used pesticide sprays for eradicating ticks are pyrethrins, permethrins, organophosphates and carbamates.

Pyrethrins are powerful neurotoxins derived from the chrysanthemum plant. They kill ticks by interrupting the electrical impulses in their nervous systems, causing paralysis and death. In large amounts, pyrethrins are toxic to mammals; they are widely used in lawn pesticides, mosquito repellents and pet tick control products. Pyrethrins break down quickly in light and bind tightly to the soil, so they are typically not a danger to the environment, according to the National Pesticide Information Center. However, human contact with large amounts of pyrethrins can cause skin irritation, coughing, wheezing and difficulty breathing.

Permethrins are man-made pesticides derived from the chemical structure of pyrethrins but with many molecular differences. Permethrins are sold as a spray to kill ticks upon contact, and they have a similar effect to pyrethrins on the nervous system, though they are less potent. Permethrins can cause skin and eye irritation, irritability to touch or sound, tingling, numbness, headache, nausea, dizziness, vomiting, fatigue and diarrhea. In extreme cases of massive exposure, permethrins can cause seizures.

Carbamates and organophosphates, or pesticides such as malathion, chlorpyrifos, diazinon and terbufos, are acetylcholinesterase inhibitors. Acetylcholinesterase is an enzyme necessary for normal nerve function, according to the Delaware Department of Health and Social Services. In ticks, these chemicals inhibit enzymes, interrupting their metabolic activity and causing death. In humans, short-term exposure can result in headache, dizziness, nausea, memory loss, tremors, weakness, sweating, tearing, salivation, pupil constriction, slowed heartbeat and diarrhea. Long-term exposure can result in liver, kidney, bone marrow and immune system damage and, in some cases, paralysis.

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