title: Heterogeneous Associations of Ecological Attributes with Tick-Borne Rickettsial Pathogens in a Periurban Landscape.
abstract: The variations in prevalence levels of two tick-borne rickettsial pathogens, Ehrlichia chaffeensis and Ehrlichia Ewingii, in a periurban environment were evaluated along with their ecological determinants. Tick life stage and sex, month of tick collection, landscape fragmentation, and ecological covariates specific to pasture and woodland sites were considered as explanatory covariates. Questing lone star ticks (Amblyomma americanum) were collected by flagging for an hour once every week during mid-April through mid-August in years 2013 and 2014. A total of 4357 adult and nymphal ticks (woodland = 2720 and pasture = 1637) were collected and assessed for pathogen prevalence by molecular methods. Female A. americanum ticks were more infected with E. chaffeensis than males or nymphs in woodland areas [♂ = 6.05%; ♀ = 12.0%; nymphs = 2.09%] and pastures [♂ = 8.05%; ♀ = 12.03%; nymphs = 3.33%], and the prevalence was influenced by edge density in the landscape. Higher E. ewingii infection was noted among female A. americanum ticks within woodland areas [♂ = 1.89%; ♀ = 2.14%; nymphs = 1.57%], but no such difference was evident in pastures [♂ = 1.03%; ♀ = 1.33%; nymphs = 1.12%]. Prevalence of E. ewingii was influenced by edge contrast index, and the percentage of pasture perimeter that was less than 20 meters from woodland areas. This study elucidates the complexity of tick-borne pathogen ecology and points to the need for further studies on the role of reservoir hosts, particularly that played by small vertebrates, which is not fully understood in the region.
authors.affiliation: 1 Kansas State Veterinary Diagnostic Laboratory, Department of Diagnostic Medicine/Pathobiology, Kansas State University , Manhattan, Kansas.|2 Center of Excellence for Vector Borne Diseases, Department of Diagnostic Medicine and Pathobiology, Kansas State University, Manhattan, Kansas.
authors.forename: Ram K
authors.initials: RK
authors.lastname: Raghavan
authors.affiliation: 3 Department of Geography, Kansas State University , Manhattan, Kansas.
authors.forename: Douglas G
authors.initials: DG
authors.lastname: Goodin
authors.affiliation: 1 Kansas State Veterinary Diagnostic Laboratory, Department of Diagnostic Medicine/Pathobiology, Kansas State University , Manhattan, Kansas.|2 Center of Excellence for Vector Borne Diseases, Department of Diagnostic Medicine and Pathobiology, Kansas State University, Manhattan, Kansas.
authors.forename: Michael W
authors.initials: MW
authors.lastname: Dryden
authors.affiliation: 1 Kansas State Veterinary Diagnostic Laboratory, Department of Diagnostic Medicine/Pathobiology, Kansas State University , Manhattan, Kansas.|4 Department of Biology, Pittsburg State University , Pittsburg, Kansas.
authors.forename: Ali
authors.initials: A
authors.lastname: Hroobi
authors.affiliation: 4 Department of Biology, Pittsburg State University , Pittsburg, Kansas.
authors.forename: David M
authors.initials: DM
authors.lastname: Gordon
authors.affiliation: 2 Center of Excellence for Vector Borne Diseases, Department of Diagnostic Medicine and Pathobiology, Kansas State University, Manhattan, Kansas.
authors.forename: Chuanmin
authors.initials: C
authors.lastname: Cheng
authors.affiliation: 2 Center of Excellence for Vector Borne Diseases, Department of Diagnostic Medicine and Pathobiology, Kansas State University, Manhattan, Kansas.
authors.forename: Arathy D
authors.initials: AD
authors.lastname: Nair
authors.affiliation: 2 Center of Excellence for Vector Borne Diseases, Department of Diagnostic Medicine and Pathobiology, Kansas State University, Manhattan, Kansas.
authors.forename: Laxmi U M R
authors.initials: LU
authors.lastname: Jakkula
authors.affiliation: 1 Kansas State Veterinary Diagnostic Laboratory, Department of Diagnostic Medicine/Pathobiology, Kansas State University , Manhattan, Kansas.
authors.forename: Gregg A
authors.initials: GA
authors.lastname: Hanzlicek
authors.affiliation: 1 Kansas State Veterinary Diagnostic Laboratory, Department of Diagnostic Medicine/Pathobiology, Kansas State University , Manhattan, Kansas.
authors.forename: Gary A
authors.initials: GA
authors.lastname: Anderson
authors.affiliation: 2 Center of Excellence for Vector Borne Diseases, Department of Diagnostic Medicine and Pathobiology, Kansas State University, Manhattan, Kansas.
authors.forename: Roman R
authors.initials: RR
authors.lastname: Ganta
mesh_terms: D000818:Animals; D002947:Cities; D004269:DNA, Bacterial / Q000235:genetics; D017753:Ecosystem; D004536:Ehrlichia / Q000145:classification* / Q000235:genetics / Q000302:isolation & purification*; D005260:Female; D007615:Kansas; D008297:Male; D009758:Nymph / Q000382:microbiology; D016133:Polymerase Chain Reaction; D013987:Ticks / Q000382:microbiology*; D015047:Zoonoses
chemical_list: D004269:DNA, Bacterial
keywords: Ehrlichia; geostatistics; rickettsia; surveillance; tick(s)