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A Survey of Tick Species in Missouri: 2019 and 2021
Henry O. Agbonpolo, MBBS, MPH Department of Housing and Neighborhood Health, Marion County Public Health Department
spreading in animals (Gettings et al., 2020). Some researchers have speculated that, due to climate change, the population of ticks is shifting from the East Coast, where there is a higher population density, to the Midwest, where there is a lower population density (Alkishe et al., 2021; Gettings et al., 2020). Additionally, the tick population is increas- ing quickly in Missouri (Hudman & Sargen- tini, 2016) and surrounding areas, including Arkansas, Illinois, Kansas, Nebraska, Okla- homa, and Tennessee. In Oklahoma (Small et al., 2019), the dominant species are the American dog tick ( Dermacentor variabilis ), black-legged deer tick ( Ixodes scapularis ), lone star tick ( Amblyomma americanum ), and Gulf Coast tick ( Amblyomma macula- tum ). Additionally, the winter tick ( Derma- centor albipictus ) has been reported to be among frequently occurring species (Mit- cham et al., 2017). In Missouri, the most frequently occurring species, however, is A . americanum , which is responsible for the transmission of the Bourbon virus (Savage et al., 2017). Further, a study conducted in Illi- nois indicated the endemicity of tickborne disease based on reports of multiple cases across human and animal populations (Her- rmann et al., 2014). Several circumstances have been implicated as risk factors for transmitting ticks and tick- borne diseases. One risk factor is the increasing number of animals as pets, with the increased prevalence of E. canis , which is commonly transferred via Rhipicephalus sanguineus , the brown dog tick (Gettings et al., 2020). Land practices can also aect the tick population. For example, a study conducted in Missouri on land management indicated that ticks are more likely to be found in unmanaged land compared with managed land. Hence, land practices such as mowing and burning are
b>?r-/? The population of ticks within North America has been increasing and expanding geographically due to climate change, reforestation, resurging deer populations, and other factors. A study was conducted to determine which species of ticks occur in Missouri during the summer season (June, July, and August). We initiated an expanded statewide surveillance using environmental samples and ticks collected by veterinary oces across the state in 2021. This work was a continuation of 2019 surveillance that involved 34 conservation areas from 22 counties. The survey was funded by the Missouri Department of Health and Senior Services, in part to determine if the invasive Haemaphysalis longicornis was present in Missouri. Among all the species detected, only four species of medical importance were identified in 2019: Amblyomma americanum, Amblyomma maculatum, Dermacentor variabilis, and Ixodes scapularis . In 2021 following an expanded surveillance, however, sampling did detect the invasive species H. longicornis in Missouri. Our study is intended to inform environmental health professionals of the prevalence of tick species of importance in Missouri, the pathogens these species harbor, and human health risks. This information can increase awareness of tick species—including new novel species—to educate the public about safety and preventive practices, as well as possibly inform the development of diagnostic and treatment protocols. Keywords: Amblyomma americanum , Amblyomma maculatum , Dermacentor variabilis , Haemaphysalis longicornis , Ixodes scapularis , tickborne diseases, vector control
Introduction The presence of ticks has been established in North America and its population is fast increasing due to reforestation, resurging deer populations, and other factors (Alk- ishe et al., 2021). Also, climate change and
increasing temperatures have been identified as contributors to the increasing tick popula- tion (Alkishe et al., 2021). Among the vari- ous tickborne diseases, ehrlichiosis (caused by Ehrlichia canis ) has been reported to be endemic in the U.S. and its prevalence is fast
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Volume 87 • Number 1
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