Diversity of piroplasms detected in blood-fed and questing ticks from several states in the United States.
Piroplasms in the genera Babesia, Theileria, and Cytauxzoon are tick-borne parasites that may be animal and human pathogens. Most piroplasms with known life cycles are transmitted by ixodid ticks; however, for many species, the vector is unknown. This study was conducted to determine the prevalence and diversity of piroplasms in ticks from several US states. Piroplasm-specific polymerase chain reaction (PCR) assays were used to test 1631 ticks from Georgia (n=486), Kentucky (n=103), Pennsylvania (n=1), Tennessee (n=626), and Texas (n=414). Ticks were either questing (n=42) or collected from animals (n=627) or humans (n=962). The 2 primary species tested were Dermacentor variabilis (n=702) and Amblyomma americanum (n=743), but Amblyomma cajennense (n=99), Amblyomma maculatum (n=16), Ixodes scapularis (n=4), I. woodi (n=1), and unidentified Amblyomma spp. nymphs (n=64) were also tested. A low prevalence of piroplasms was detected with 37 (2.3%), 35 (2.1%), and 9 (0.6%) ticks positive for Theileria spp., Babesia spp., or Cytauxzoon felis, respectively. Based on sequence analysis, at least 6 Babesia spp. were detected and 15 of the 35 (41%) Babesia-positive ticks were A. americanum, 19 (56%) were D. variabilis, and one (3%) was an I. scapularis. Nine Babesia-positive ticks were removed from humans from Kentucky (n=1), Georgia (n=2), Texas (n=5), and Pennsylvania (n=1). Three Babesia-positive ticks were questing A. americanum which represents the first report of Babesia-infected questing Amblyomma in the US. Theileria infections were only detected in A. americanum, and all sequences were similar to white-tailed deer associated Theileria spp. C. felis was only detected in D. variabilis. These data suggest that A. americanum may be a vector of Babesia spp., although experimental studies are needed to confirm vector competence. Finally, these data demonstrate a high diversity of piroplasms in both questing and partially fed ticks in the US; although, host-blood meals can be present in non-questing ticks.
Southeastern Cooperative Wildlife Disease Study, University of Georgia, Athens, GA, USA; Warnell School of Forestry and Natural Resources, University of Georgia, Athens, GA, USA. Electronic address: barbarashock@gmail.com.
Barbara C
BC
Shock
Vector-Borne Diseases Section, Communicable and Environmental Diseases, Tennessee Department of Health, Nashville, TN, USA.
Abelardo
A
Moncayo
Vector-Borne Diseases Section, Communicable and Environmental Diseases, Tennessee Department of Health, Nashville, TN, USA.
Sara
S
Cohen
Department of Forensic and Investigative Genetics, University of North Texas Health Science Center, Fort Worth, TX, USA.
Elizabeth A
EA
Mitchell
Department of Forensic and Investigative Genetics, University of North Texas Health Science Center, Fort Worth, TX, USA; Creative Testing Solutions, 2424 W. Erie Drive, Tempe, AZ, USA.
Phillip C
PC
Williamson
Georgia Poison Center, 80 Jesse Hill Junior Dr. SE, Atlanta, GA, USA.
Gaylord
G
Lopez
Georgia Department of Human Resources, Division of Public Health, 2 Peachtree St. NW, Atlanta, GA, USA.
Laurel E
LE
Garrison
Southeastern Cooperative Wildlife Disease Study, University of Georgia, Athens, GA, USA; Warnell School of Forestry and Natural Resources, University of Georgia, Athens, GA, USA.
Michael J
MJ
Yabsley
D000818:Animals; D001061:Appalachian Region / Q000453:epidemiology; D001096:Arachnid Vectors / Q000469:parasitology*; D001403:Babesia / Q000235:genetics / Q000302:isolation & purification; D001483:Base Sequence; D016054:DNA, Protozoan / Q000737:chemistry / Q000235:genetics; D004283:Dog Diseases / Q000453:epidemiology / Q000469:parasitology*; D004285:Dogs; D006801:Humans; D026863:Ixodidae / Q000469:parasitology*; D008969:Molecular Sequence Data; D016792:Piroplasmida / Q000235:genetics* / Q000302:isolation & purification; D016133:Polymerase Chain Reaction; D015995:Prevalence; D011528:Protozoan Infections / Q000453:epidemiology / Q000469:parasitology*; D017422:Sequence Analysis, DNA; D013045:Species Specificity; D013781:Texas / Q000453:epidemiology; D016794:Theileria / Q000235:genetics / Q000302:isolation & purification
D016054:DNA, Protozoan
Amblyomma americanum; Babesia; Cytauxzoon; Dermacentor variabilis; Theileria; Tick-transmitted diseases