Colorado tick fever
Encyclopedia
Colorado Tick Fever (also called Mountain tick fever, American tick fever, and "American mountain tick fever") is an obtuse viral infection transmitted from the bite of an infected tick
(Dermacentor andersoni). It should not be confused with the bacterial tick-borne infection, Rocky Mountain spotted fever
.
The type species
of the genus
Coltivirus
, Colorado tick fever virus (CTFV) infects haemopoietic cells, particularly erythrocytes, which explains how the virus is transmitted by ticks and also accounts for the incidence of transmission via blood transfusion.
s have been reported. The virus which causes Colorado Tick Fever may stay in the blood for as long as four months after onset of the illness.
First signs of symptoms can occur about 3–6 days after the initial tick bite, although it can have incubation periods of up to 20 days. Patients usually experience a two-staged fever and illness which can continue for three days, diminish, and then return for another episode of 1–3 days. The virus has the ability to live in the blood stream for up to 120 days; therefore coming in contact without proper precautions and the donation of blood are prohibited.
Initial symptoms include: fever, chills, headaches, pain behind the eyes, light sensitivity, muscle pain, generalized malaise abdominal pain, nausea, vomiting as well as a flat or pimply rash. During the second phase of the virus a high fever can return with an increase in symptoms. CTF can be very severe in cases involving children and have even required hospitalization. Complications with this disease have included aseptic meningitis, encephalitis, and hemorrhagic fever, but these are rare.
CTF is seasonal, mostly occurring in the Rocky Mountain region of the United States and usually in altitudes from 4,000 to 10,000 feet. Patients with CTF are mostly campers and young males, who most likely have been bitten because of their occupational activities.
Detection of antibodies is possible.
, and the rare occurrence of bleeding disorders. Someone who suspects that they have been bitten by a tick or is starting to show signs of CTF should contact their physician immediately.
Make sure after you pull it out that the nose is not left in your skin. This can cause painful infection to occur.
A match or flame should NOT be used to remove a tick. This method, once thought safe, can cause the tick to regurgitate expelling any disease it may be carrying into the bite wound.
Contracting the CTF virus is thought to provide long lasting immunity against reinfection. However it is always wise to be on the safe side and try to prevent tick bites.
Tick
Ticks are small arachnids in the order Ixodida, along with mites, constitute the subclass Acarina. Ticks are ectoparasites , living by hematophagy on the blood of mammals, birds, and sometimes reptiles and amphibians...
(Dermacentor andersoni). It should not be confused with the bacterial tick-borne infection, Rocky Mountain spotted fever
Rocky Mountain spotted fever
Rocky Mountain spotted fever is the most lethal and most frequently reported rickettsial illness in the United States. It has been diagnosed throughout the Americas. Some synonyms for Rocky Mountain spotted fever in other countries include “tick typhus,” “Tobia fever” , “São Paulo fever” or “febre...
.
The type species
Species
In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...
of the genus
Genus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...
Coltivirus
Coltivirus
Coltivirus is a genus of viruses that infects vertebrates, invertebrates, and plants. It includes the causative agent of Colorado tick fever....
, Colorado tick fever virus (CTFV) infects haemopoietic cells, particularly erythrocytes, which explains how the virus is transmitted by ticks and also accounts for the incidence of transmission via blood transfusion.
Epidemiology
The disease develops from March to September, with the highest infections occurring in June. The disease is found almost exclusively in the western United States and Canada, mostly in high mountain areas such as Colorado and Idaho. The CTFV was first isolated from human blood in 1944.Virology
The virus particle, like other Coltiviruses, is ~80 nm in diameter and is generally non-enveloped. The double stranded RNA viral genome is ~20,000bp long and is divided into 11 segments, which are termed Seg-1 to Seg-12. Viral replication in infected cells is associated with characteristic cytoplasmic granular matrices. Evidence suggests that viral presence in mature erythrocytes is a result of replication of the virus in hematopoitic erythrocyte precursor cells and simultaneous maturation of the infected immature cells rather than off direct entry and replication of CTFV in mature erythrocytes.Tick
The wood tick is usually found attached to a host, but when it is without a host it hides in cracks and crevices as well as soil. If for some reason the tick is not able to find a host before the winter months, it will stay under groundcover until spring when it can resume its search. The wood tick typically does not seek out available hosts in the hottest summer months as well. Adult ticks, for the most part, tend to climb to the top of grass and low shrubs to attach themselves to a host that is wandering by. These ticks are able to attach to their hosts by secreting a cement-like substance from their mouths and inserting it into the host.Transmission and symptoms
Colorado Tick Fever is acquired by tick bite. There is no evidence of natural person-to-person transmission. However, rare cases of transmission from blood transfusionBlood transfusion
Blood transfusion is the process of receiving blood products into one's circulation intravenously. Transfusions are used in a variety of medical conditions to replace lost components of the blood...
s have been reported. The virus which causes Colorado Tick Fever may stay in the blood for as long as four months after onset of the illness.
First signs of symptoms can occur about 3–6 days after the initial tick bite, although it can have incubation periods of up to 20 days. Patients usually experience a two-staged fever and illness which can continue for three days, diminish, and then return for another episode of 1–3 days. The virus has the ability to live in the blood stream for up to 120 days; therefore coming in contact without proper precautions and the donation of blood are prohibited.
Initial symptoms include: fever, chills, headaches, pain behind the eyes, light sensitivity, muscle pain, generalized malaise abdominal pain, nausea, vomiting as well as a flat or pimply rash. During the second phase of the virus a high fever can return with an increase in symptoms. CTF can be very severe in cases involving children and have even required hospitalization. Complications with this disease have included aseptic meningitis, encephalitis, and hemorrhagic fever, but these are rare.
CTF is seasonal, mostly occurring in the Rocky Mountain region of the United States and usually in altitudes from 4,000 to 10,000 feet. Patients with CTF are mostly campers and young males, who most likely have been bitten because of their occupational activities.
Diagnosis
A combination of clinical signs, symptoms and laboratory tests can confirm the likelihood of having CTF. Some tests include complement fixation to Colorado tick virus, Immunofluoresence for Colorado tick fever, and some other common laboratory findings suggestive of CTF including leucopenia, thrombocytopenia, and mildly elevated liver enzyme levels.Detection of antibodies is possible.
Treatment
At this time there is no specific treatment for CTF. The first thing to do is make sure the tick is fully removed from the skin, then Acetaminophen and analgesics can be used to help relieve the fever and pain. Aspirin is not recommended for children it has been linked to Reye’s syndrome in some viral illnesses. Salicylates should not be used because of thrombocytopeniaThrombocytopenia
Thrombocytopenia is a relative decrease of platelets in blood.A normal human platelet count ranges from 150,000 to 450,000 platelets per microliter of blood. These limits are determined by the 2.5th lower and upper percentile, so values outside this range do not necessarily indicate disease...
, and the rare occurrence of bleeding disorders. Someone who suspects that they have been bitten by a tick or is starting to show signs of CTF should contact their physician immediately.
Proper tick removal
Ticks should be removed promptly and carefully with tweezers and by applying gentle steady traction. The tick's body should not be crushed when it is removed and the tweezers should be placed as close to the skin as possible to avoid leaving tick mouth parts in the skin. Ticks should not be removed with bare hands. Hands should be protected by gloves and/or tissues and thoroughly washed with soap and water after the removal process. This should be performed with great care.Make sure after you pull it out that the nose is not left in your skin. This can cause painful infection to occur.
A match or flame should NOT be used to remove a tick. This method, once thought safe, can cause the tick to regurgitate expelling any disease it may be carrying into the bite wound.
Prevention
To avoid tick bites and infection, experts advise:- Avoid tick infested areas, especially during the warmer months.
- Wear light colored clothing so ticks can be easily seen. Wear a long sleeved shirt, hat, long pants, and tuck pant legs into socks.
- Walk in the center of trails to avoid overhanging grass and brush.
- Check your body every few hours for ticks when you spend a lot of time outdoors in tick infested areas. Ticks are most often found on the thigh, arms, underarms and legs. Ticks can be very small (no bigger than a pinhead). Look carefully for new "freckles".
- Use insect repellentInsect repellentAn insect repellent is a substance applied to skin, clothing, or other surfaces which discourages insects from landing or climbing on that surface. There are also insect repellent products available based on sound production, particularly ultrasound...
s containing DEETDEETN,N-Diethyl-meta-toluamide, abbreviated DEET, is a slightly yellow oil. It is the most common active ingredient in insect repellents...
on your skin or permethrinPermethrinPermethrin is a common synthetic chemical, widely used as an insecticide, acaricide, and insect repellent. It belongs to the family of synthetic chemicals called pyrethroids and functions as a neurotoxin, affecting neuron membranes by prolonging sodium channel activation. It is not known to...
on clothing. Be sure to follow the directions on the container and wash off repellents when going indoors. - Remove attached ticks immediately.
Contracting the CTF virus is thought to provide long lasting immunity against reinfection. However it is always wise to be on the safe side and try to prevent tick bites.