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Colorado Tick Fever

Mountain Fever

Colorado tick fever is a rare, self-limiting febrile illness caused by an RNA virus of the genus Coltivirus. It is spread through tick bites to people living or traveling in the endemic regions of the western United States and western Canada. It presents clinically with non-specific symptoms, usually in adult males, although central nervous system involvement in children has also been reported.


Presentation

Colorado tick fever (CTF) is a self-limiting, often benign, febrile illness spread to humans through infected tick bites [1] [2]. A spurt in CTF cases is usually noticed from April until August as the ticks are active in these months. Ticks get infected with the virus when feeding on the blood of rodents such as mice, squirrels, and chipmunks, and then transmit the virus while feeding on either humans or animals. Rarely, the infection can be transmitted via blood transfusion, but otherwise, person to person transmission has not been reported. The onset of symptoms can occur anytime between 1 to 14 days after the tick bite.

The clinical presentation is non-specific with fever, malaise, myalgias, arthralgias, lassitude, fatigue, sore throat, nausea, or vomiting. A maculopapular rash with palatal spots may be present in some patients. Some patients may have the classic CTF "biphasic" or "saddleback" fever characterized by fever for a few days, followed by improvement in symptoms for the next few days, and then another short phase of fever with constitutional symptoms. A majority of patients have a self-limiting illness and recover without sequelae although the weakness can persist for several weeks. There have been rare reports of central nervous system involvement with meningitis and encephalitis in children [1] [2] [3] [4] [5], as well as in some adults [6]. Other uncommon clinical presentations include photophobia [7], diarrhea, hepatitis, epididymo-orchitis, arthritis, hemorrhagic diathesis, carditis, pneumonia, and even coma [1] [2] [8] [9].

Fever
  • Mountain tick fever; Mountain fever; American mountain fever Bolgiano EB, Sexton J. Tick-borne illnesses. In: Walls RM, Hockberger RS, Gausche-Hill M, eds. Rosen's Emergency Medicine: Concepts and Clinical Practice . 9th ed.[nlm.nih.gov]
  • Ecology of Colorado tick fever. Annu Rev Microbiol. 1988; 42 :49–64. [ PubMed ] [ Google Scholar ] Emmons RW, Oshiro LS, Johnson HN, Lennette EH. Intra-erythrocytic location of Colorado tick fever virus.[pubmedcentral.nih.gov]
  • This disease is caused by infection with the Colorado tick fever virus, a member of the Coltivirus genera. In the past, it has been named Mountain fever or American mountain fever. CTF virus was first isolated from human blood in 1944.[web.archive.org]
  • […] a high fever can return with an increase in symptoms.[en.wikipedia.org]
Chills
  • Symptoms generally include acute onset of fever, headache, chills, and myalgias; illness often lasts for 3 weeks or more.[ncbi.nlm.nih.gov]
  • .- ) Certain infectious and parasitic diseases Clinical Information A febrile illness characterized by chills, aches, vomiting, leukopenia, and sometimes encephalitis.[icd10data.com]
  • Symptoms fever headache chills light sensitivity myalgias malaise fatigue and malaise, for weeks to months nausea, diarrhea light sensitivity rare pneumonitis myocarditis hepatitis Signs and tests Complement fixation antibody test Immunofluorescence antibody[whatislyme.com]
  • Symptoms of Colorado tick fever include: Fever and chills. Headache, often severe. Muscle aches (myalgias). Sensitivity to light (photophobia). Medical treatment can help relieve the symptoms of Colorado tick fever.[myhealth.alberta.ca]
  • The initial symptoms of the disease often include fever, chills, headache, muscular and skeletal pain, and malaise. Other symptoms may include nausea, vomiting, stomach pain, light sensitivity and sore throat.[aldf.com]
Malaise
  • Symptoms fever headache chills light sensitivity myalgias malaise fatigue and malaise, for weeks to months nausea, diarrhea light sensitivity rare pneumonitis myocarditis hepatitis Signs and tests Complement fixation antibody test Immunofluorescence antibody[whatislyme.com]
  • Col·o·ra·do tick fever \ ˌkäl-ə-ˈrad-(ˌ)ō-, -ˈräd- \ : a mild disease of the western United States and western Canada that is characterized by intermittent fever, malaise, headaches, myalgia, and the absence of a rash and is caused by a reovirus (species[merriam-webster.com]
  • The initial symptoms of the disease often include fever, chills, headache, muscular and skeletal pain, and malaise. Other symptoms may include nausea, vomiting, stomach pain, light sensitivity and sore throat.[aldf.com]
  • The clinical presentation is non-specific with fever, malaise, myalgias, arthralgias, lassitude, fatigue, sore throat, nausea, or vomiting. A maculopapular rash with palatal spots may be present in some patients.[symptoma.com]
  • Symptoms, which are often non-specific, begin 3 to 5 days after the bite with an abrupt onset of fever and any of these: headaches, chills, malaise, photophobia, myalgias, nausea, vomiting, diarrhea and abdominal pain.[lymediseaseassociation.org]
Fatigue
  • Initial clinical diagnosis of CTF is based on the patient's history of travel to endemic areas with probable tick bites followed by fever and fatigue.[symptoma.com]
  • Symptoms fever headache chills light sensitivity myalgias malaise fatigue and malaise, for weeks to months nausea, diarrhea light sensitivity rare pneumonitis myocarditis hepatitis Signs and tests Complement fixation antibody test Immunofluorescence antibody[whatislyme.com]
  • […] for a rare disease Colorado tick fever Disease definition Colorado tick fever (CTF) is an acute arboviral infection caused by a Coltivirus transmitted by an infected tick and characterized by a biphasic fever with headache, myalgias, arthralgias, and fatigue[orpha.net]
  • In contrast, many adults over the age of 30 tend to have lingering symptoms, primarily fatigue and malaise, for weeks to months. Death from Colorado tick fever is extremely uncommon, but has been reported in a few pediatric cases.[coloradoticks.org]
Biphasic Fever
  • Abstract Colorado tick fever (CTF) virus elicits an acute illness in humans, producing nonspecific flu-like symptoms and a biphasic fever in approximately 50% of patients.[ncbi.nlm.nih.gov]
  • Homepage Rare diseases Search Search for a rare disease Colorado tick fever Disease definition Colorado tick fever (CTF) is an acute arboviral infection caused by a Coltivirus transmitted by an infected tick and characterized by a biphasic fever with[orpha.net]
  • fever Rash – uncommon and short-lived (can be macular, maculopapular, or petechial) Central nervous system diseases (stiff neck, confusion, meningitis, meningoencephalitis) (rare), life-threatening illnesses or death (rare) E. chaffeensis, E. ewingii[arupconsult.com]
Nausea
  • Symptoms fever headache chills light sensitivity myalgias malaise fatigue and malaise, for weeks to months nausea, diarrhea light sensitivity rare pneumonitis myocarditis hepatitis Signs and tests Complement fixation antibody test Immunofluorescence antibody[whatislyme.com]
  • In some cases, macular, maculopapular, or petechial rash and/or stiff neck, nausea, vomiting, abdominal pain, diarrhea, and sore throat may also occur.[orpha.net]
  • The clinical presentation is non-specific with fever, malaise, myalgias, arthralgias, lassitude, fatigue, sore throat, nausea, or vomiting. A maculopapular rash with palatal spots may be present in some patients.[symptoma.com]
  • Symptoms, which are often non-specific, begin 3 to 5 days after the bite with an abrupt onset of fever and any of these: headaches, chills, malaise, photophobia, myalgias, nausea, vomiting, diarrhea and abdominal pain.[lymediseaseassociation.org]
Vomiting
  • In some cases, macular, maculopapular, or petechial rash and/or stiff neck, nausea, vomiting, abdominal pain, diarrhea, and sore throat may also occur.[orpha.net]
  • The clinical presentation is non-specific with fever, malaise, myalgias, arthralgias, lassitude, fatigue, sore throat, nausea, or vomiting. A maculopapular rash with palatal spots may be present in some patients.[symptoma.com]
  • Symptoms, which are often non-specific, begin 3 to 5 days after the bite with an abrupt onset of fever and any of these: headaches, chills, malaise, photophobia, myalgias, nausea, vomiting, diarrhea and abdominal pain.[lymediseaseassociation.org]
  • Other symptoms include: Feeling weak all over and muscle aches Headache behind the eyes Lethargy (sleepiness) or confusion Nausea and vomiting Rash (may be light colored) Sensitivity to light ( photophobia ) Skin pain Sweating The health care provider[nlm.nih.gov]
Abdominal Pain
  • In some cases, macular, maculopapular, or petechial rash and/or stiff neck, nausea, vomiting, abdominal pain, diarrhea, and sore throat may also occur.[orpha.net]
  • Symptoms, which are often non-specific, begin 3 to 5 days after the bite with an abrupt onset of fever and any of these: headaches, chills, malaise, photophobia, myalgias, nausea, vomiting, diarrhea and abdominal pain.[lymediseaseassociation.org]
  • Abdominal pain and vomiting occur occasionally. The first attack lasts about two days.[britannica.com]
  • Signs and Symptoms Following infection, symptoms that may occur include fever, headache, chills, light sensitivity, muscle aches, malaise, nausea, vomiting, diarrhea, abdominal pain, and rarely a rash.[columbia-lyme.org]
Diarrhea
  • Symptoms fever headache chills light sensitivity myalgias malaise fatigue and malaise, for weeks to months nausea, diarrhea light sensitivity rare pneumonitis myocarditis hepatitis Signs and tests Complement fixation antibody test Immunofluorescence antibody[whatislyme.com]
  • In some cases, macular, maculopapular, or petechial rash and/or stiff neck, nausea, vomiting, abdominal pain, diarrhea, and sore throat may also occur.[orpha.net]
  • Other uncommon clinical presentations include photophobia, diarrhea, hepatitis, epididymo-orchitis, arthritis, hemorrhagic diathesis, carditis, pneumonia, and even coma.[symptoma.com]
  • Symptoms, which are often non-specific, begin 3 to 5 days after the bite with an abrupt onset of fever and any of these: headaches, chills, malaise, photophobia, myalgias, nausea, vomiting, diarrhea and abdominal pain.[lymediseaseassociation.org]
Loss of Appetite
  • Symptoms of Colorado tick fever include: fever up to 105 F chills severe headache light sensitivity muscle aches skin tenderness loss of appetite nausea vomiting abdominal pain weakness and fatigue faint rash It’s important to note that symptoms of Colorado[healthline.com]
  • The symptoms of Heartland virus are headaches, muscle aches, diarrhea, loss of appetite and nausea. 364D Richettsiosis This disease is found in California and other west coast areas where the Pacific Coast tick is found.[orkin.com]
Photophobia
  • Sensitivity to light (photophobia). Medical treatment can help relieve the symptoms of Colorado tick fever. Current as of: July 30, 2018 Author: Healthwise Staff Medical Review: William H.[myhealth.alberta.ca]
  • Other uncommon clinical presentations include photophobia, diarrhea, hepatitis, epididymo-orchitis, arthritis, hemorrhagic diathesis, carditis, pneumonia, and even coma.[symptoma.com]
  • Symptoms, which are often non-specific, begin 3 to 5 days after the bite with an abrupt onset of fever and any of these: headaches, chills, malaise, photophobia, myalgias, nausea, vomiting, diarrhea and abdominal pain.[lymediseaseassociation.org]
  • Other symptoms include: Feeling weak all over and muscle aches Headache behind the eyes Lethargy (sleepiness) or confusion Nausea and vomiting Rash (may be light colored) Sensitivity to light ( photophobia ) Skin pain Sweating The health care provider[nlm.nih.gov]
Myalgia
  • Symptoms generally include acute onset of fever, headache, chills, and myalgias; illness often lasts for 3 weeks or more.[ncbi.nlm.nih.gov]
  • Typical symptoms of fever, myalgia, and headache were common, but gastrointestinal symptoms were also prominent in 20% of the patients. Twenty percent were hospitalized; no deaths or permanent sequelae were noted.[ncbi.nlm.nih.gov]
  • CTF illness includes fever, headache, and severe myalgia lasting for weeks.[ncbi.nlm.nih.gov]
  • Symptoms fever headache chills light sensitivity myalgias malaise fatigue and malaise, for weeks to months nausea, diarrhea light sensitivity rare pneumonitis myocarditis hepatitis Signs and tests Complement fixation antibody test Immunofluorescence antibody[whatislyme.com]
  • Col·o·ra·do tick fever \ ˌkäl-ə-ˈrad-(ˌ)ō-, -ˈräd- \ : a mild disease of the western United States and western Canada that is characterized by intermittent fever, malaise, headaches, myalgia, and the absence of a rash and is caused by a reovirus (species[merriam-webster.com]
Headache
  • Symptoms generally include acute onset of fever, headache, chills, and myalgias; illness often lasts for 3 weeks or more.[ncbi.nlm.nih.gov]
  • Typical symptoms of fever, myalgia, and headache were common, but gastrointestinal symptoms were also prominent in 20% of the patients. Twenty percent were hospitalized; no deaths or permanent sequelae were noted.[ncbi.nlm.nih.gov]
  • CTF illness includes fever, headache, and severe myalgia lasting for weeks.[ncbi.nlm.nih.gov]
  • The initial symptoms of the disease often include fever, chills, headache, muscular and skeletal pain, and malaise. Other symptoms may include nausea, vomiting, stomach pain, light sensitivity and sore throat.[aldf.com]
  • Symptoms fever headache chills light sensitivity myalgias malaise fatigue and malaise, for weeks to months nausea, diarrhea light sensitivity rare pneumonitis myocarditis hepatitis Signs and tests Complement fixation antibody test Immunofluorescence antibody[whatislyme.com]
Lethargy
  • Other symptoms include: Feeling weak all over and muscle aches Headache behind the eyes Lethargy (sleepiness) or confusion Nausea and vomiting Rash (may be light colored) Sensitivity to light ( photophobia ) Skin pain Sweating The health care provider[nlm.nih.gov]
  • Other symptoms include: Feeling weak all over and muscle aches Headache behind the eyes Lethargy (sleepiness) or confusion Nausea and vomiting Rash (may be light-colored) Sensitivity to light ( photophobia ) Skin pain Sweating Exams and Tests The health[ufhealth.org]
  • Other symptoms include: Feeling weak all over and muscle aches Headache behind the eyes Lethargy (sleepiness) or confusion Nausea and vomiting Rash (may be light colored) Sensitivity to light ( photophobia ) Skin pain Sweating Exams and Tests The health[mountsinai.org]
Neck Stiffness
  • Cerebrospinal fluid analysis may be warranted in CTF patients presenting with neck stiffness or features of encephalitis and may reveal mild protein elevation with lymphocytic pleocytosis.[symptoma.com]
  • CNS illnesses are commonly characterized by severe headache, sensory impairment, neck stiffness and light sensitivity. Diagnosis An initial diagnosis is based on the patient’s signs and symptoms and confirmation depends on laboratory testing.[aldf.com]

Workup

Initial clinical diagnosis of CTF is based on the patient's history of travel to endemic areas with probable tick bites followed by fever and fatigue. Physical examination findings are not specific although a maculopapular rash and nuchal rigidity may be present. Routine laboratory tests like complete blood count, erythrocyte sedimentation rate, and liver function tests are ordered. Atypical lymphocytes [7], relative lymphocytosis, thrombocytopenia, and leukopenia are often noticed in CTF patients. Certain patients may have elevated levels of liver transaminases. The diagnosis of CTF can be confirmed with the detection of viral RNA and specific immunoglobulins in serum. Reverse-transcriptase polymerase chain reaction (RT-PCR) is a more useful test in early phases of the disease since serological tests may not be positive until 2-3 weeks after the patient's initial clinical presentation. Cerebrospinal fluid analysis may be warranted in CTF patients presenting with neck stiffness or features of encephalitis and may reveal mild protein elevation with lymphocytic pleocytosis. Finally, genetic material can be isolated from the tick to confirm the presence of a virus [10].

Radiological investigations are not helpful in the diagnosis or management of CTF except in cases of central nervous system involvement. Magnetic resonance imaging can be considered in cases presenting with features of encephalitis or other serious neurological diseases.

Treatment

  • If complications develop, treatment will be aimed at controlling the symptoms. Colorado tick fever usually goes away by itself and is not dangerous.[nlm.nih.gov]
  • What is the treatment for CTF? There is no specific treatment for CTF. Symptomatic relief includes treatment of fever and pain with acetominophen and analgesics.[web.archive.org]
  • Other blood tests may include: Complete blood count ( CBC ) Liver function tests Treatment There are no specific treatments for this viral infection. The provider will make sure the tick is fully removed from the skin.[ufhealth.org]

Prognosis

  • Prognosis The prognosis for patients with Colorado tick fever is excellent, even in cases complicated by neurologic symptoms. Although prompt recovery is the expected outcome, rare fatalities have been reported.[emedicine.com]
  • Outlook (Prognosis) Colorado tick fever usually goes away by itself and is not dangerous.[ufhealth.org]

Etiology

  • The reverse transcriptase PCR method is a promising tool for the early diagnosis of CTF viral infection, or for ruling out CTF virus as the etiologic agent, in order to facilitate appropriate medical support.[ncbi.nlm.nih.gov]
  • Pathophysiology and Etiology The cause of Colorado tick fever is infection with the causative agent that is transmitted by a tick bite. This agent is a double-stranded RNA virus of the genus Coltivirus in the family Reoviridae.[emedicine.com]

Epidemiology

  • Additional descriptive epidemiologic data were obtained by medical record abstraction. Ninety-one cases were identified from 1995 to 2003, resulting in an overall annual incidence of 2.7 per 1,000,000 population.[ncbi.nlm.nih.gov]
  • This study summarizes national surveillance data for CTF from 2002 through 2012 and examines trends in the epidemiology and testing of identified CTF cases.[ncbi.nlm.nih.gov]
  • Colorado tick fever: clinical, epidemiologic, and laboratory aspects of 228 cases in Colorado in 1973-1974. Ann Intern Med . 1978 Mar. 88(3):303-10. [Medline] . Crowder CD, Rounds MA, Phillipson CA, et al.[emedicine.com]
Sex distribution
Age distribution

Pathophysiology

  • Pathophysiology and Etiology The cause of Colorado tick fever is infection with the causative agent that is transmitted by a tick bite. This agent is a double-stranded RNA virus of the genus Coltivirus in the family Reoviridae.[emedicine.com]

Prevention

  • Heightened awareness for the disease and tick prevention messages should be part of public health measures to further decrease the incidence of disease.[ncbi.nlm.nih.gov]
  • However, limiting exposure to ticks is presently the most effective method of prevention. Return to top[web.archive.org]
  • Prevention of tick-borne diseases. Med Clin North Am . 2002 Mar. 86(2):219-38. [Medline] . Centers for Disease Control and Prevention. Colorado Tick Fever: Prevention. Available at . January 13, 2015; Lindquist L, Vapalahti O.[emedicine.com]

References

Article

  1. Spruance SL, Bailey A. Colorado tick fever: a review of 115 laboratory confirmed cases. Arch Intern Med. 1973;131:288-293
  2. Goodpasture HC, Poland JD, Francy DB, et al. Colorado tick fever: clinical, epidemiologic, and laboratory aspects of 228 cases in Colorado in 1973-1974. Ann Intern Med.1978;88(3):303-310.
  3. Fraser CH, Schiff DW. Colorado tick fever encephalitis: report of a case. Pediatrics. 1962;29:187-190
  4. Florio L, Miller MS, Mugrage ER. Colorado tick fever: recovery of virus from human cerebrospinal fluid. J. infect Dis. 1952; 91:285-289
  5. Silver HK, Meiklejohn G, Kempe CH. Colorado tick fever. An J Dis Child. 1961;101: 30-36
  6. Romero JR, Simonsen KA. Powassan encephalitis and colorado tick fever. Infect Dis Clin North Am. 2008;22(3):545-559,
  7. Meagher KE, Decker CF. Other tick-borne illnesses: tularemia, Colorado tick fever, tick paralysis. Dis Mon. 2012;58 (6):370-376.
  8. Hierholzer WJ, Barry DW. Colorado tick fever pericarditis. JAMA. 1971;217:825
  9. Emmons RW, Schade HI. Colorado tick fever simulating acute myocardial infarction. JAMA.1972;222:87-88
  10. Crowder CD, Rounds MA, Phillipson CA, et al. Extraction of total nucleic acids from ticks for the detection of bacterial and viral pathogens. J Med Entomol. 2010;47(1):89-94.

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Last updated: 2018-06-22 04:43