Tuesday, September 01, 2009

RESEARCH NEWS: Four-Posters Reduce Numbers of Lyme-Carrying Ticks 71%

A device called the "4-poster" Deer Treatment Bait Station, developed and patented by scientists with the Agricultural Research Service (ARS), was highly effective at reducing the number of ticks infected with the Lyme disease bacterium in a six-year U.S. Department of Agriculture (USDA) study in five Northeastern states—Maryland, New Jersey, New York, Connecticut and Rhode Island—where the disease is endemic.

In the $2.1 million USDA Northeast Areawide Tick Control Project, investigators noted a 71 percent overall reduction in the number of ticks infected with the Lyme disease bacterium during summer months when most people get the disease. If the 4-poster is used in areas where the disease is endemic, this should translate to a corresponding 71 percent decrease in Lyme disease cases, according to Durland Fish, a professor of epidemiology at Yale School of Public Health and principal investigator for the project. The effectiveness of the 4-poster ranged from 60 to 82 percent among the seven individual 2-square-mile study sites.

The device is a bin that contains corn, with insecticide-laden paint rollers mounted at the bin's corners. When a deer-the primary carrier of the blacklegged tick, Ixodes scapularis, which carries the Lyme disease bacterium—inserts its muzzle into the bin to feed, it must rub its head, neck and ears against the insecticide-treated rollers. When the deer subsequently grooms itself, the insecticide is spread enough to protect the animal's entire body.

Developed by ARS scientists at the agency's Knipling-Bushland U.S. Livestock Insects Research Laboratory in Kerrville, Texas, the 4-poster's efficacy could be boosted to more than 90 percent by using newer, more effective insecticides that were not available at the start of the USDA study, according to J. Mathews Pound, an entomologist at the Kerrville laboratory and a co-investigator on the study.

The results of the study have been published in a series of 11 papers in the August 2009 issue of the medical journal Vector-borne and Zoonotic Diseases. The articles are available free online.

Source: USDA-ARS

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