TY - JOUR
T1 - Prevalence and Strains of Colorado Tick Fever Virus in Rocky Mountain Wood Ticks in the Bitterroot Valley, Montana
AU - Williamson, Brandi N.
AU - Fischer, Robert J.
AU - Lopez, Job E.
AU - Ebihara, Hideki
AU - Schwan, Tom G.
N1 - Funding Information:
This work was supported by the Division of Intramural Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health. We thank Ashley Kelly Palacio, Forest Hoyt, Sandra Stewart, and Paul Policastro for field help, Mike and Michael Zielinski and employees of the BNF, USDA, for collecting ticks, Austin Athman for help with figures, and Stephanie Seifert for article review.
Publisher Copyright:
© 2019, Mary Ann Liebert, Inc., publishers 2019.
PY - 2019/9
Y1 - 2019/9
N2 - The Rocky Mountain wood tick, Dermacentor andersoni, has long been known to transmit human pathogens. Within the Bitterroot Valley, Ravalli County, Montana, these agents include Rickettsia rickettsii, Francisella tularensis, and Colorado tick fever virus (CTFV). Found in the western United States where wood ticks occur, CTFV causes a biphasic, febrile illness in humans and persists in enzootic cycles involving the ticks and small mammals. CTFV belongs to the genus Coltivirus, family Reoviridae, whose genome consists of 12 double-stranded RNA segments. Previous studies revealed the presence of CTFV-infected ticks and rodents in select locations within the valley in the 1960s and 1970s, using animal and cell culture methods for detection. We aimed to determine the range and prevalence of the virus in adult questing ticks throughout the valley using molecular tools and to examine the genomic variation between virus strains. Adult D. andersoni ticks were collected during 2002-2003 and 2009-2013. RNA extractions and reverse transcription-polymerase chain reaction were performed on 921 ticks, of which 61 ticks were positive for CTFV, resulting in a 6.6% prevalence of infection. Four genetic loci, one from each of the segments 9, 10, 11, and 12, within the viral genome were sequenced. Reassortment was detected between CTFV sequence strains within the valley. This study confirmed the prevalence of CTFV in D. andersoni ticks within the Bitterroot Valley, which has remained at levels found in the 1950s and 60s. Additional CTFV sequences were obtained and evidence of reassortment was observed between strains within the valley.
AB - The Rocky Mountain wood tick, Dermacentor andersoni, has long been known to transmit human pathogens. Within the Bitterroot Valley, Ravalli County, Montana, these agents include Rickettsia rickettsii, Francisella tularensis, and Colorado tick fever virus (CTFV). Found in the western United States where wood ticks occur, CTFV causes a biphasic, febrile illness in humans and persists in enzootic cycles involving the ticks and small mammals. CTFV belongs to the genus Coltivirus, family Reoviridae, whose genome consists of 12 double-stranded RNA segments. Previous studies revealed the presence of CTFV-infected ticks and rodents in select locations within the valley in the 1960s and 1970s, using animal and cell culture methods for detection. We aimed to determine the range and prevalence of the virus in adult questing ticks throughout the valley using molecular tools and to examine the genomic variation between virus strains. Adult D. andersoni ticks were collected during 2002-2003 and 2009-2013. RNA extractions and reverse transcription-polymerase chain reaction were performed on 921 ticks, of which 61 ticks were positive for CTFV, resulting in a 6.6% prevalence of infection. Four genetic loci, one from each of the segments 9, 10, 11, and 12, within the viral genome were sequenced. Reassortment was detected between CTFV sequence strains within the valley. This study confirmed the prevalence of CTFV in D. andersoni ticks within the Bitterroot Valley, which has remained at levels found in the 1950s and 60s. Additional CTFV sequences were obtained and evidence of reassortment was observed between strains within the valley.
KW - Dermacentor andersoni
KW - reassortment
KW - vector borne
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U2 - 10.1089/vbz.2018.2407
DO - 10.1089/vbz.2018.2407
M3 - Article
C2 - 30939106
AN - SCOPUS:85072058176
SN - 1530-3667
VL - 19
SP - 694
EP - 702
JO - Vector-Borne and Zoonotic Diseases
JF - Vector-Borne and Zoonotic Diseases
IS - 9
ER -