Estimating the Geographic Distribution of Host-Seeking AdultAmblyomma americanum(Acari: Ixodidae) in Florida

Abstract

The lone star tick, Amblyomma americanum, is the most commonly reported human-biting tick in the southeastern United States and is a vector for several human and livestock pathogens. Although it is endemic to Florida, little is known about the ecological preferences and current spatial distribution within the state. Using occurrence records of adult A. americanum collected between August 2015 and September 2016, a logistic regression model was used to estimate environmental associations, as well as to predict the distribution of the tick at a one hectare resolution. Occurrence of adult lone star ticks was associated with land cover and bioclimatic variables, namely the presence of forested areas and precipitation seasonality. The estimated spatial distribution indicated that central and northern regions show greater suitability than the southern half of the state. Furthermore, areas predicted to be suitable for the species decreases from north to south with very little area deemed suitable in the far southern reaches of the state. High heterogeneity in the distribution of suitable habitat has implications for the distribution of tick-borne disease cases in the state. The subcounty resolution of the estimated distribution is an improvement over distributions currently published and may better inform the public and state or federal agencies of potential risk of exposure to A. americanum and its associated pathogens.

Modeling Potential Habitat for Amblyomma Tick Species in California

“…Similar modeling methods have successfully preempted tick establishment in novel ranges, for example the establishment of Ixodes scapularis in Canada [32,33], and the retrospective range expansion of I. scapularis across the eastern USA [34]. The potential distribution of A. americanum in the USA has been predicted using SDM methods [35,36,37,38], but typically only for eastern states or based on presence data at a coarse county-level spatial resolution. To the best of our knowledge, distributions of A. maculatum, A. cajennense, and A. mixtum have not been predicted for the USA using SDM methods.…”

Standardized Ixodid Tick Survey in Mainland Florida

“…National and regional analyses that relied on information from various collection sources [4,5] indicate that selected species should be widely distributed in the region. Recently, Kessler and colleagues [14] developed a more spatially detailed analysis of Amblyomma americanum within the state and reported that the predicted species distribution was anticipated to be substantially more nuanced, with much of the spatial heterogeneity in the species distribution associated with landcover, temperature, and precipitation patterns, which was obscured in national-level analyses which focused on regional climatic variability.…”

Modeling the Distribution of Medically Important Tick Species in Florida

“…We used georeferenced records from three years of tick collections performed from late 2015 through 2018 containing observations of adult Amblyomma americanum , Dermacentor variabilis , or Ixodes scapularis [39,40]. The initial dataset included 1956 surveys of presence or absence for each of the three species.…”

“…Temporally, these transects were repeated regularly throughout the study period (repeated surveys of each transect). Collection efforts occurred year-round to ensure all sites were sampled with the same intensity regardless of when individual species’ peak seasonal activity occurred [39,40]. The methods for collection are described in further detail elsewhere [39,40].…”

“…Collection efforts occurred year-round to ensure all sites were sampled with the same intensity regardless of when individual species’ peak seasonal activity occurred [39,40]. The methods for collection are described in further detail elsewhere [39,40]. The repeated sampling of multiple biotopes within sites produced a total of 1956 presence or absence records for the dataset.…”