<i>Notes from the Field:</i>Investigation of Colorado Tick Fever Virus Disease Cases — Oregon, 2018

McDonald, Emily G.; George, Douglas A.; Rekant, Steven I.; Curren, Emily J; DeBess, Emilio; Hedberg, Katrina; Lutz, Jon; Faith, Jennifer; Kaisner, Heather; Fawcett, R.H.; Sherer, Rebecca; Kanyuch, Rob; Gudmundsson, Audrey; Gardner, N. R.; Salt, Marianne; Kosoy, Olga; Velez, Jason O.; Staples, Erin; Fischer, Marc; Gould, Carolyn V.

doi:10.15585/mmwr.mm6812a4

Cited by 6 publications

(4 citation statements)

References 6 publications

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“…By providing current information about CTFV in western tick populations, we hope to increase physician awareness of CTF in areas of risk. Based on these results, as well as recent results from tick surveillance in Montana (Williamson et al, 2019 ), tick and human surveillance in Wyoming (Geissler et al, 2014 ), and human case follow-up and serological surveillance in Oregon (McDonald et al, 2019 ), CTF may still be a tick-borne disease of public health importance (Brackney et al, 2010 ). CTFV-infected ticks are abundant in many regions in the west, including popular recreational areas, and thus it is reasonable for a health care provider who has a patient presenting with a biphasic fever to consider CTF as a differential diagnosis, particularly if the patient lives or recreates in mountainous areas or reports tick bite exposure.…”

Section: Discussionmentioning

confidence: 85%

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Colorado Tick Fever Virus in the Far West: Forgotten, but Not Gone

Padgett

Kjemtrup

Novak

et al. 2022

Vector-Borne and Zoonotic Diseases

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In the past few decades, reported human cases of Colorado tick fever in the western United States have decreased dramatically. The goal of this study was to conduct surveillance for Colorado tick fever virus (CTFV) in Dermacentor ticks in recreational sites in Colorado, Wyoming, and California to determine whether the virus is still present in Dermacentor ticks from these states. Surveillance focused on regions where surveys had been conducted in the 1950s, 1960s, and 1970s. Adult Rocky Mountain wood ticks ( Dermacentor andersoni ), Pacific Coast ticks ( Dermacentor occidentalis ), and winter ticks ( Dermacentor albipictus ) were tested by PCR. A subset of PCR-positive D. andersoni ticks ( n = 7) were cultured in Vero cells. CTFV-positive Rocky Mountain wood ticks were found in all states: Colorado (58% prevalence), Wyoming (21%), and California (4%). Although no winter ticks tested positive, Pacific Coast ticks tested positive in one county (Siskiyou County, 15% prevalence) and were positive only in a location that also maintained Rocky Mountain wood ticks and golden mantled ground squirrels, a known CTFV host. In summary, CTFV is prevalent in D. andersoni and D. occidentalis in regions where they are sympatric in California and in D. andersoni in Colorado and Wyoming. Although the number of human CTFV cases has declined dramatically, this decrease in reported disease does not appear to be due to the disappearance or even the decline in prevalence of this virus in ticks in historically endemic regions of the country.

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Section: Discussionmentioning

confidence: 85%

“…This test is available at some state public health laboratories and at the U.S. Centers for Disease Control and Prevention (CDC). Later in disease progression, IgG antibodies can be detected and a fourfold increase in titer supports a confirmed diagnosis (McDonald et al, 2019 ).…”

Section: Introductionmentioning

confidence: 99%

Colorado Tick Fever Virus in the Far West: Forgotten, but Not Gone

Padgett

Kjemtrup

Novak

et al. 2022

Vector-Borne and Zoonotic Diseases

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“…Other reported complications include meningoencephalitis, hepatitis, pericarditis, myocarditis, atypical pneumonia, disseminated intravascular coagulation, and epididymo-orchitis [ 14 , 15 ]. In general, the number of CTFV cases reported annually has decreased over time [ 14 , 16 ]. It is unclear if this reflects changes in the testing or reporting practices and certain states where the disease is found not having given it a notifiable condition.…”

Section: Introductionmentioning

confidence: 99%

“…It is unclear if this reflects changes in the testing or reporting practices and certain states where the disease is found not having given it a notifiable condition. However, recent increases in case counts were seen in selected states, but it is unclear if the incidence is related to human activity or increased clinical awareness [ 16 ]. Although CTFV has been a recognized cause of human illness since the 1940s, very limited genetic information is available for CTFV, with only one complete genome sequence available for the exemplar CTFV isolate, Florio.…”

Section: Introductionmentioning

confidence: 99%

Genomic Evaluation of the Genus Coltivirus Indicates Genetic Diversity among Colorado Tick Fever Virus Strains and Demarcation of a New Species

et al. 2021

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The type species of the genus Coltivirus, Colorado tick fever virus (CTFV), was discovered in 1943 and is the most common tick-borne viral infection in the Western US. Despite its long history, very little is known about the molecular diversity of viruses classified within the species Colorado tick fever coltivirus. Previous studies have suggested genetic variants and potential serotypes of CTFV, but limited genetic sequence information is available for CTFV strains. To address this knowledge gap, we report herein the full-length genomes of five strains of CTFV, including Salmon River virus and California hare coltivirus (CTFV-Ca). The sequence from the full-length genome of Salmon River virus identified a high genetic identity to the CTFV prototype strain with >90% amino acid identity in all the segments except segment four, suggesting Salmon River virus is a strain of the species Colorado tick fever coltivirus. Additionally, analysis suggests that segment four has been associated with reassortment in at least one strain. The CTFV-Ca full-length genomic sequence was highly variable from the prototype CTFV in all the segments. The genome of CTFV-Ca was most similar to the Eyach virus, including similar segments six and seven. These data suggest that CTFV-Ca is not a strain of CTFV but a unique species. Additional sequence information of CTFV strains will improve the molecular surveillance tools and provide additional taxonomic resolution to this understudied virus.

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Reoviruses: Colorado Tick Fever Virus and Other Vector-Borne Reoviruses

Staples

2022

Viral Infections of Humans

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Notes from the Field:Investigation of Colorado Tick Fever Virus Disease Cases — Oregon, 2018

Cited by 6 publications

References 6 publications

Colorado Tick Fever Virus in the Far West: Forgotten, but Not Gone

Colorado Tick Fever Virus in the Far West: Forgotten, but Not Gone

Genomic Evaluation of the Genus Coltivirus Indicates Genetic Diversity among Colorado Tick Fever Virus Strains and Demarcation of a New Species

Reoviruses: Colorado Tick Fever Virus and Other Vector-Borne Reoviruses

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