A new device may offer a better way to prevent tick bites

A new device may offer a better way to prevent tick bites

A new device may offer a better way to prevent tick bites

A new device may offer a better way to prevent tick bites

Controlled Release Device (CRD). Credit: VERY ONE (2022). DOI: 10.1371/journal.pone.0269150

When it comes to preventing tick bites—especially in light of the dramatic, decades-long rise in tick-borne diseases—insect sprays are helpful, but not optimal.

For example, DEET is designed to prevent swift mosquitoes from landing on their host, where they bite and fly away in seconds. Ticks, on the other hand, do not fly, but lurk in ambush and then slowly climb up to their host until they settle in, feed and can stay for days.

“Unfortunately, most repellents were developed for mosquitoes 75 years ago and not for ” says vector-borne disease expert Stephen Rich, professor of microbiology at the University of Massachusetts Amherst and executive director of the New England-based UMass Amherst Center of Excellence for Vector-borne Diseases (NEWVEC). “DEET, the gold standard, works pretty well, but the holy grail would was to have another repellent tool—not a contact repellent like DEET, but a spatial repellent—that works as well or better than DEET against ticks.”

Experiments in Rich’s Laboratory of Medical Zoology used a new controlled-release device developed by scientist-entrepreneur Noel Elman. Rich and colleagues tested the effects on ticks after releasing the synthetic pyrethroids transfluthrin and metofluthrin into a small, transparent chamber equipped with three vertical climbing rods. Ticks do not come into direct contact with repellents; rather, the active ingredients create more of a “force field” that alters and slows the tick’s progress toward its target.

Isključeno: Novi uređaj možda nudi bolji način za sprječavanje ugriza krpelja

Experimental setup. The controlled release device was placed in the upper left corner of the experimental chamber. Three vertical climbing poles were lined up along the upper side. The camera recorded tick climbing from the perspective shown for quantitative analysis of behavior based on vertical movement. Credit: VERY ONE (2022). DOI: 10.1371/journal.pone.0269150

The results, published today, November 8, in the journal VERY ONEfound that two spatial repellents were effective in altering the behavior of ticks, making them less likely to climb vertically and more likely to detach or fall from the stick.

“While we still have a lot of work to do, these innovative findings prove the principle that these spatial repellents change tick behavior in a way that we hope will lead to less ,” says Rich, senior author.

The paper’s lead author, Eric Siegel, helped design the vision system that precisely tracked the ticks’ movements in the experimental chamber. “People often use the word ‘repellency,’ and we set out to redefine repellency in tick protection and find ways to measure it,” says Siegel, a lab technician who will begin his Ph.D. studies in microbiology under Rich. “There is so much we still don’t know about ticks’ sense of smell [smell] and delicious [taste] mechanisms, and that was the biggest challenge in these experiments, as is generally the case in the development of protective products.”

The compounds were tested against three major ticks that bite humans in the US: I. scapularis (the black-legged or deer tick), which can spread Lyme disease and anaplasmosis, among other diseases; D. variabilis (American dog tick), which can transmit Rocky Mountain spotted fever and tularemia; and A. americanum (lone star tick), which can spread ehrlichiosis and has been associated with red meat allergy.

Isključeno: Novi uređaj možda nudi bolji način za sprječavanje ugriza krpelja

Concentration gradient from CFD simulation, 25 minutes after release. Concentration gradients obtained by CFD simulation are plotted for (A) transfluthrin and (B) metofluthrin, 25 minutes after release. Taking into account the induction time of 20 minutes before tick introduction, the concentrations represented tick exposure halfway (5 minutes) during the test. A vertical concentration gradient was observed, with higher concentrations (warmer colors) present at the bottom of the chamber and lower concentrations (cooler colors) at the top. Two perspectives are illustrated: viewing the chamber from the perspective of the camera (right) and the side with the CRD (left). The CRD is placed in the upper left corner of the right frame perspective and the upper center of the side perspective. Credit: VERY ONE (2022). DOI: 10.1371/journal.pone.0269150

Trials revealed that transfluthrin deterred 75% of D. variabilis, 67% of A. americanum and 50% of I. scapularis. Metofluthrin was slightly more effective, deterring 81% of D. variabilis, 73% of A. americanum and 72% of I. scapularis.

“We were impressed not only by the rejection, but also in a tick,” says co-author Elman, founder and CEO of GearJump Technologies, which designed a controlled-release device that can be attached to a soldier’s boot. Many ticks in the experiments became slower, less mobile and appeared to be in a “drunk state “, according to the newspaper.

Elman approached Rich several years ago to design and conduct experiments using the device with various repellents. The next step is to conduct experiments with real host animals.

“Repellents probably won’t stop ticks from attacking us,” says Rich. “We’re hoping the repellents will help keep them off us, and that’s really where the battle lines should be drawn.”

Researchers can envision a day when such devices will be commercially available to the general population. Until then, research will continue. “We still largely don’t know how the chemicals we use work,” says Siegel. “Once we do that, we can develop and improve these measures in a more targeted way.”

More information:
Eric L. Siegel et al, The spatial repellents transfluthrin and metofluthrin affect the behavior of Dermacentor variabilis, Amblyomma americanum, and Ixodes scapularis in an in vitro vertical climbing assay, VERY ONE (2022). DOI: 10.1371/journal.pone.0269150

Quote: New device may offer better way to prevent tick bites (2022, November 8) Retrieved November 9, 2022 from https://phys.org/news/2022-11-device.html

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