Biology subjects

Paskewitz, S. M.

Publications and source records attributed to Paskewitz, S. M..

4 recordsLinked to original sources

bioRxiv2022

Semi-field evaluations of three botanically derived repellents against the blacklegged tick, Ixodes scapularis (Acari: Ixodidae)

Three compounds derived from botanicals sources, ethyl perillyl carbonate, geranyl isovalerate, and citronellyl cyclobutane carboxylate, were tested for repellent activity against Ixodes scapularis Say in a semi-field trial. Tick drags were treated with the compounds or with N, N-diethyl-m-toluamide (DEET) at high (0.25mg/cm2) or low (0.15mg/cm2) concentrations. Negative controls included untreated drags and drags treated with acetone, the carrier for all repellents. Freshly treated drags (within 20 minutes) were used to collect I. scapularis ticks at a county park in Wisconsin. To assess effectiveness, we measured tick encounter rates, detachment rate, and time to detachment. None of the repellent treatments resulted in significantly fewer encounters compared to both control treatments. However, the percentage of ticks that detached within 3 min was significantly higher on drags treated with repellents compared to controls. DEET was the most effective, repelling 69.7 - 87% of ticks by 3 min, but the effectiveness of the three test compounds was still high, ranging from 42% to 87% of ticks detaching by 3 min. For time to detachment, there were no significant differences between DEET and the three test compounds. We conclude that these botanically-derived repellents were effective against I. scapularis in a semi-field trial and could be viable alternatives to DEET.

zoology↗

bioRxiv2022

Influence of Nesting Material Composition on Tick Tube Use by Peromyscus leucopus

Host-targeted acaricides are a valuable tool for the reduction of ticks and tick-borne disease. Tick tubes (also known as tick control tubes) are commercially available products containing permethrin-treated nesting materials. Through superficial acaricide application to Peromyscus mice, tick tubes reduce populations of the blacklegged tick, Ixodes scapularis Say. Results of prior field trials have varied, suggesting that mouse behavior as well as the scale of the intervention and the composition of the local host community are important determinants of efficacy. Here we evaluated behaviors related to nest material collection by P. leucopus. Two forms of nest materials used in commercial tick tube products (cotton batting and balls) were assessed through side-by-side comparisons over a four-week period. We quantified cotton uptake by monitoring weekly changes in material weight and used video surveillance to categorize and assess mouse behaviors. The odds of cotton batting being taken from tubes was 2.14 times greater than cotton balls but the process was less efficient; mice removed 0.35 g less cotton batting for each removal event and required 2.17 times longer to complete the removal. While cotton balls were readily carried in the jaws of mice, batting required separating smaller fragments from the mass before placement in the oral cavity. Video surveillance suggested that a small number of mice were super users and responsible for 22% of the 119 visits in which material was removed. Combined, material weight loss and video-captured removal events improve our understanding of host usage of nest materials but also raise questions about dissemination of the material in nests of the local mouse community.

ecology↗

bioRxiv2022

Integrated Tick Management in the Upper Midwest: Impact of Invasive Vegetation Removal and Host-targeted Acaricides on Ixodes scapularis Infestation and Borrelia burgdorferi Prevalence of Small Mammals

Integration of tick management strategies has been suggested to overcome ecological variation in tick, host, pathogen, and habitat, yet empirical evidence assessing combined treatment effect on blacklegged ticks, Ixodes scapularis Say, is limited. In this 5-year study (2014-2018) we tested whether combining two methods targeting tick/mammal interactions could reduce juvenile I. scapularis parasitism of two small mammal species, Peromyscus leucopus Rafinesque and Tamias striatus Linnaeus. Infection of small mammals with Borrelia burgdorferi was used to evaluate host exposure to feeding ticks. Using a factorial design, removal of invasive vegetation (Amur honeysuckle, Lonicera maackii Ruprecht and common buckthorn, Rhamnus cathartica Linnaeus) was coupled with deployments of permethrin-treated cotton nesting materials (tick tubes) and evaluated against control sites. Removal of invasive vegetation resulted in lower captures of T. striatus suggesting that treatment impacted reservoir activity in the plots. Deployments of permethrin-treated cotton were effective at reducing the frequency of juvenile I. scapularis parasitism of P. leucopus by 91% across the study compared to controls. However, tick tubes did not offer consistent protection against mouse exposure to B. burgdorferi exposure. An additive negative effect was detected for juvenile tick intensity on P. leucopus when tick tubes were combined with invasive vegetation removal. We conclude that integration of these two methods provides very limited benefit and that permethrin treatment alone offers the best option for reducing I. scapularis infestation on P. leucopus.

ecology↗

bioRxiv2021

Identification of public submitted tick images: a neural network approach

Ticks and tick-borne diseases represent a growing public health threat in North America and Europe. The number of ticks, their geographical distribution, and the incidence of tick-borne diseases, like Lyme disease, are all on the rise. Accurate, real-time tick-image identification through a smartphone app or similar platform could help mitigate this threat by informing users of the risks associated and by providing researchers and public health agencies with better data on tick activity and geographic range. We report the development and validation of a convolutional neural network, a type of deep learning algorithm, trained on a dataset of more than 12,000 user-generated tick images. The model, which we call "TickIDNet," is trained to identify the three most common tick species found on humans in the U.S.: Amblyomma americanum, Dermacentor variabilis, and Ixodes scapularis. At baseline, TickIDNet scores an 87.8% identification accuracy across all three species, outperforming the accuracy of identifications done by a member of the general public or healthcare professionals. However, the model fails to match the performance of experts with formal entomological training. We find that image quality, particularly the size of the tick in the image (measured in pixels), plays a significant role in the networks ability to correctly identify an image: images where the tick is small are less likely to be correctly identified because of the small object detection problem in deep learning. TickIDNets performance can be increased by using confidence thresholds to introduce an "unsure" class and building image submission pipelines that encourage better quality photos. Our findings suggest that deep learning represents a promising frontier for tick identification that should be further explored and deployed as part of the toolkit for addressing the public health consequences of tick-borne diseases.

bioinformatics↗