Surveillance of Host-Seeking Ticks in the Flint Hills Region (USA) and Associations with Environmental Determinants

Abstract

Diversity and phenology of host-seeking ticks were studied in the Flint Hills region of the USA, which is a prominent region for raising beef cattle. Between a two-year period from 2015–2017, ticks were collected using the dragging method from 9 distant locations, 6 of which were studied seasonally and 3 continuously throughout the study period. Of the 10,055 ticks collected, 76.5% were the Lonestar tick (Amblyomma americanum), 14% were American dog tick (Dermacentor variabilis), and 9.1% were Gulf Coast tick (A. maculatum). The blacklegged tick, Ixodes scapularis were also found, albeit in low numbers. The host-seeking activity of all three predominant tick species peaked once during the late spring, summer months in the region. The phenology of all ticks was positively associated with accumulated temperature and photoperiod. Additionally, the Normalized Vegetation Difference Index (NDVI) was associated with A. americanum, and saturation deficit and relative humidity were negatively associated with D. variabilis and A. maculatum tick phenology, respectively. This finding is useful to predict the times during a year in which cattle are at higher risk for exposure to these ticks and associated pathogens.

Phenology of five tick species in the central Great Plains

“…We identified five tick species of public health importance. Previous studies conducted at sites near, and including some of our sites, have identified much the same set of species [ 4 , 10 , 17 – 19 ]. Amblyomma americanum was the most abundant, comprising approximately 97% of all individual ticks collected.…”

“…americanum activities with the historical questing patterns [ 25 , 26 ], shows a general earlier shift in peak timings of up to 2 months across the sites. The changes in peak timings could be attributed in part to warming climate [ 10 ], which has been associated with north-and-westward ranges expansion of the tick [ 27 – 30 ]. Phenology studies in warmer southeastern parts of United States have reported peak activity between March and April for A .…”

“…The occurrence of a second questing peak has been attributed to early larvae to nymph molting with newly molted nymphs actively seeking for host before winter onset [ 34 ]. Early winter onset in the region—when compared to the past period—[ 10 ] could have driven early nymphal diapause, however this could change with the warming conditions.…”

“…The phenology of ticks in the Central Great Plains is likely influenced by an interplay of factors, including temperature, humidity, vegetation type, and host availability [ 10 ], given the region’s distinctive blend of grasslands, forests, and agricultural landscapes. Different tick species’ seasonal prevalence, abundance, and distribution, on these landscapes might offer important clues to their ecological preferences, and likely responses to change in climate conditions [ 11 ].…”

Geographical distribution and pathogenesis of ticks and tick-borne viral diseases

“…According to research findings, A. americanum may be infected with the BRBV at the larva or nymph stages ( Spare et al, 2021 ; Aziati et al, 2022 ). Multiple BRBV detections in A. americanum indicate that these viruses have similar life cycles and routes of transmission ( Miller, 2018 ; Savage et al, 2018 ).…”