Preventing Ticks and Lyme Disease: Scientists Test New Strategy

Throughout human history, ticks have performed notorious roles, usually as bloodthirsty villains. According to DreamBible.com, "to dream of ticks represents an annoyance in your life that forces you to be extra careful." The third plague sent upon Egypt, described in Exodus 8:16-18, describes lice miraculously forming from dust; some scholars have proposed that the word denotes not lice, but ticks. In Shakespeare's Troilus and Cressida, to imagine oneself as a tick serves as an insult:

Would the fountain of your mind were clear again,
that I might water an ass at it! I had rather be a
tick in a sheep than such a valiant ignorance.

Today, ticks appear in scientific and medical literature, usually after they have done their worst damage. Scientists are seeking ways to prevent infected ticks from biting deer, mice, or people, because that is how ticks share the bacteria that cause Lyme disease. Once those bacteria get kicking, people have chills, fever, even palsy that can last a lifetime. There were over 150,000 confirmed and probable cases of Lyme in the U.S. in five recent years, reflecting a steadily increasing trend over previous years.

Reported cases of Lyme disease by year in the United States. Source: Centers for Disease Control and Prevention.

Money for Good Work

The Northeastern IPM Center is funding research to foil the villains while reducing the use of pesticides. We've funded research on rosemary oil, a food-grade compound that ticks hate as much as synthetic pesticides. Then came deer-feeding stations. Ticks cling to the necks of deer as they feed on corn, but these contraptions swab them with a deadly solution to rub out the bad actors.

In 2016, the Center awarded Andrew Li of the USDA Agricultural Research Service $49,469 to evaluate integrated control measures for keeping ticks off of school grounds. They'll bring out the deer feeding stations for a return performance, along with rodent bait boxes. The bait targets rodents that carry the blacklegged tick, one of the most significant vectors of Lyme.

The bait boxes consist of three components: a child-resistant box, a non-toxic bait block attractant, and an applicator that applies fipronil, the same insecticide as the commercial pet product Frontline for flea and tick control. It kills ticks, not the bacteria that cause Lyme. When a rodent (typically a mouse or a chipmunk) enters the box to feed or investigate, it is treated with the insecticide, interrupting the Lyme transmission cycle.

Prevention for Schools

"Tick-borne Lyme disease is the most important vector-borne human disease in the United States," Li said. "It is anticipated that the risk for tick bite and Lyme disease can be reduced by significantly lowering the population density of questing nymphs in environment."

According to the National Climate Assessment, it is unclear how climate change will impact Lyme disease, yet "several studies in the Northeast have linked tick activity and Lyme disease incidence to climate, specifically abundant late spring and early summer moisture."1

The authors of the National Climate Assessment also point to increased favorable habitat for ticks, a lengthened season when disease can be transmitted, higher tick densities due to milder winters and increased rodent populations, and people spending increased time outdoors.2

"To the best of my knowledge," Li added, "this is the first host-targeted tick IPM project conducted on school grounds. Anything we learn from this project would help improve tick control and Lyme prevention efforts in the Northeast."

References

1 Horton, R., G. Yohe, W. Easterling, R. Kates, M. Ruth, E. Sussman, A. Whelchel, D. Wolfe, and F. Lipschultz, 2014: Ch. 16: Northeast. Climate Change Impacts in the United States: The Third National Climate Assessment, J. M. Melillo, Terese (T.C.) Richmond, and G. W. Yohe, Eds., U.S. Global Change Research Program, 16-1-nn. http://nca2014.globalchange.gov/report/regions/northeast Accessed on April 25, 2017.

2 Luber, G., K. Knowlton, J. Balbus, H. Frumkin, M. Hayden, J. Hess, M. McGeehin, N. Sheats, L. Backer, C. B. Beard, K. L. Ebi, E. Maibach, R. S. Ostfeld, C. Wiedinmyer, E. Zielinski-Gutiérrez, and L. Ziska, 2014: Ch. 9: Human Health. Climate Change Impacts in the United States: The Third National Climate Assessment, J. M. Melillo, Terese (T.C.) Richmond, and G. W. Yohe, Eds., U.S. Global Change Research Program, 220-256. doi:10.7930/J0PN93H5 http://nca2014.globalchange.gov/report/sectors/human-health Accessed on April 25, 2017.

— by CHRIS GONZALES


The Northeastern IPM Center promotes integrated pest management for reducing risks to human health and the environment. If republishing our news, please acknowledge the source ("From Northeast IPM Insights") along with a link to our website.