From August 2, 2005
*Note: The chemicals discussed in this piece are hazardous and while baiting systems reduce exposure, these systems can result in the dispersal of toxic chemicals in homes and the environment. Please see Beyond Pesticides' fact sheet on least toxic tick control.
Rejects Pesticide Spraying, New Tools Emerge for Lyme Disease Prevention
(Beyond Pesticides, August 2, 2005) Most of the pesticides that are registered for backyard spraying for tick control, typically synthetic pyrethroids, have been linked to asthma and cancer. Marc Dolan, a senior research scientist with the Centers for Disease Control (CDC), recently told the Associated Press (AP) that 75 percent of the public is opposed to spraying for ticks, despite high tick populations in the Northeast. This has lead to several new options in the battle against Lyme Disease.
While the ticks that transmit Lyme Disease are called deer ticks, both deer and rodents serve as their primary hosts. With this in mind, CDC developed a bait system (Maxforce Tick Management System), which rodents are lured into plastic boxes where a wick coats their fur with fipronil, a pesticide that kills ticks for up to six weeks. The bait stations are installed seasonally by professional applicators. The active ingredient in the system is still a toxic chemical, however, bait stations are preferred to spraying because exposure is not widespread. Fipronil is the active ingredient in popular pet treatments as well.
Another bait system, the 4-Poster Deer Treatment Bait Station, feeds deer a mixture of corn and permethrin, an insecticide that later kills feeding ticks. The four poster system was developed by the U.S. Department of Agriculture (USDA) and is licensed to the American Lyme Disease Foundation, which gets a small royalty on sales.
As with the fipronil in the mouse baits, permethrin is also a hazardous chemical, but may kill ticks with reduced public exposure. J. Allen Miller, a supervisory research engineer with the USDA's Agricultural Research Service, told the AP that a study in five Northeast states found 4-Poster killed 70 percent to 90 percent of ticks in two years. “It's not spread over the environment,” Miller said, and spraying uses about 1,500 times as much insecticide as the 4-Poster system.
However, Durland Fish, science adviser to the foundation, said told the AP that while it endorses the 4-Poster system, it needs improvements. One drawback is that it cannot be used near homes because children could touch the exposed chemical.
Dr. Fish says other strategies are in development, including a fungal spray safer than other pesticides, a Lyme disease vaccine for mice and use of nematodes, tiny worms that eat ticks.
According to the CDC, 21,273 cases of Lyme disease were reported in 2003, mostly in New England and mid-Atlantic states. The CDC estimates only 10 percent of cases are reported because Lyme disease often causes only mild, flu-like symptoms.
Symptoms also can include fever, fatigue, joint and muscle aches, headache and, in some people, a bull's-eye rash. Untreated, it can cause neurological problems, personality changes, sleep disturbances, disabling joint pain and swelling, meningitis or heart problems.
Immunologist Dr. Steven Schutzer of University of Medicine and Dentistry of New Jersey in Newark, who has done research on tick habitats, said infected patients seem to be seeking help sooner, when antibiotics are most effective. He said few patients follow the "long sleeves, long pants tucked in" strategy to avoid tick bites, so people should avoid areas with ankle-deep brush where ticks and mice are likely to be.
For more information, see Beyond Pesticides factsheet on ticks.