tick-borne relapsing fever

Tick-Borne Relapsing Fever (TBRF) Symptoms and Characteristics

Tick-borne relapsing fever (TBRF) is a bacterial infection transmitted by ticks, characterized by recurring episodes of fever. The symptoms of TBRF typically include:

• High fever: A sudden high fever (104–105 F) accompanied by chills, headache, and muscle ache [2].
• Recurring episodes: Symptoms arise abruptly, presenting with a high fever as well as rapid breathing and fast heart rate, then transitioning to decreased body temperature and apparent recovery [4].
• Chills or shakes: A common symptom of TBRF, indicating the onset of a new episode of fever [5].
• Fatigue: Feeling extremely tired or exhausted due to recurring episodes of fever [5].
• Nausea or vomiting: Some people may experience nausea or vomiting during an episode of fever [5].

Characteristics and Transmission

TBRF is transmitted by ticks, which are typically infected with the bacteria Borrelia. The infection can be spread through tick bites, and symptoms usually develop about a week after being bitten by an infected tick [2]. TBRF is not very common, but most cases occur in specific regions where ticks are prevalent.

References

• [1] Symptoms typically include high fever (e.g., 103⁰ F), along with shaking chills, headaches, muscle or joint aches, nausea, vomiting, and possibly rash.
• [2] Apr 12, 2023 — Persons with TBRF develop a sudden high fever (104–105 F), chills, headache, and muscle ache about a week after being bitten by an infected tick.
• [4] Symptoms arise abruptly, presenting with a high fever as well as rapid breathing and fast heart rate, then transitioning to decreased body temperature and apparent recovery.
• [5] May 15, 2024 — Signs and symptoms · Chills or shakes · Fatigue · Nausea or vomiting · Headache · Muscle and joint aches.

Symptoms of Tick-Borne Relapsing Fever

Tick-borne relapsing fever (TBRF) is characterized by recurring episodes of fever, accompanied by other non-specific symptoms. The main signs and symptoms of TBRF include:

• High fever: A high fever is the primary symptom of TBRF, which can last for a few days, go away for a week, and then come back.
• Headaches: Headaches are a common symptom of TBRF, often accompanied by muscle and joint aches.
• Muscle and joint aches: Muscle and joint pain are also common symptoms of TBRF.
• Chills or shakes: Chills or shakes can occur during fever episodes.
• Vomiting: Vomiting is another symptom that can occur during fever episodes.
• Abdominal pain: Abdominal pain can also be a symptom of TBRF.

These symptoms can recur repeatedly if the infection is not treated, with cycles of 2-5 days of fever followed by periods of apparent recovery. It's essential to seek medical attention if you suspect you have been bitten by an infected tick and are experiencing these symptoms.

References:

• [1] Tick-borne relapsing fever (TBRF) is an infection spread by a certain kind of tick. The telltale symptom is a high fever that lasts for a few days, goes away for a week, and then comes back.
• [4] The main symptoms of TBRF are high fever, headaches, and muscle and joint aches.
• [6] Symptoms of TBRF include repeated episodes of fever, along with headache, muscle and joint aches, and nausea.
• [10] Other symptoms can include: Chills or shakes. Fatigue. Nausea or vomiting. Headache. Muscle and joint aches.
• [12] Symptoms of tick-borne relapsing fever are recurring episodes of fever accompanied by other non-specific symptoms including headaches, muscle pain, joint pain, chills, vomiting, and abdominal pain.

Diagnostic Tests for Tick-Borne Relapsing Fever

Tick-borne relapsing fever (TBRF) can be diagnosed through various laboratory tests, which are crucial in confirming the diagnosis and ruling out other conditions. Here are some of the diagnostic tests used to diagnose TBRF:

• Peripheral Blood Smear: This is typically the first step in diagnosis, where a sample of peripheral blood is examined under a microscope for the presence of spirochetes ( spiral-shaped bacteria). [8]
• Microscopic Visualization: Direct microscopic visualization of borreliae in a Giemsa-stained thick blood smear is considered the gold-standard diagnosis for relapsing fever borreliae. [9]
• Polymerase Chain Reaction (PCR): PCR testing is available from some commercial laboratories or through CDC, and it can be used to detect the presence of TBRF-causing bacteria in whole blood samples. Some PCR methods may not distinguish between HTRF and STRF. [1][10]
• Serologic Testing: Serologic testing is also available for diagnosing TBRF, particularly when diagnosis is suspected later in the course of illness. Repeated testing with a rise in Immunoglobulin G (IgG) is suggestive of infection. [12]

Other Considerations

It's essential to note that laboratory testing for tickborne disease includes serology and nucleic acid amplification testing (NAAT), and the appropriate testing strategy depends on the clinical presentation and exposure history. [6] Additionally, other tick-borne diseases such as Lyme disease, Rocky Mountain spotted fever (RMSF), ehrlichiosis, anaplasmosis, babesiosis, tularemia, Colorado tick fever, and Bourbon virus should be considered in the differential diagnosis. [11][14]

Tick Species Transmission

TBRF is transmitted to humans via the bite of infected Ornithodoros ticks (such as Ornithodoros hermsii). A definitive diagnosis of TBRF can be made by detecting Borrelia spirochetes in the patient's blood, bone marrow, or cerebrospinal fluid. [15]

References

[1] Molecular testing for HTRF by PCR is available from some commercial laboratories or through CDC. [8] TBRF results in circulating spirochete bacteria (spirochetemia), which can be visualized during microscopic blood smear examination. [9] The gold-standard diagnosis for relapsing fever borreliae is direct microscopic visualization of borreliae in a Giemsa-stained thick blood smears. [10] PCR is more sensitive than microscopy and may also be used during asymptomatic periods or soon after treatment initiation. [12] Serology may also be used to diagnose tick-borne relapsing fever, particularly in situations in which diagnosis is suspected later in the course of illness. [14] Also consider contacting the public health department for additional testing options based on exposure history (eg, Bourbon virus, Colorado tick fever virus).

Treatment Options for Tick-Borne Relapsing Fever

Tick-borne relapsing fever (TBRF) can be effectively treated with antibiotics. The primary treatment options include:

• Tetracycline: A single dose of 500 mg or a course of tetracycline every 6 hours for 7-10 days is recommended [4].
• Doxycycline: A single dose of 200 mg or a course of doxycycline twice daily for 7-10 days is also effective [3]. In fact, treatment with doxycycline has been found to be safe and efficacious in preventing TBRF after suspected exposure to ticks in high-risk environments [5].
• Penicillin: A combination of penicillin and doxycycline or azithromycin for a longer duration has also been used to treat LBRF, which is another form of tick-borne relapsing fever [6].

Post-Exposure Prophylaxis

In addition to treating the infection, post-exposure prophylaxis (PEP) with doxycycline for 5 days has been recommended to prevent TBRF after suspected exposure to ticks in high-risk environments [7].

Important Considerations

It is essential to note that treatment should be initiated promptly after diagnosis. The risk of Jarisch-Herxheimer reaction (JHR) appears to be lower in TBRF, but it can still occur [9]. Therefore, patients should be monitored for any signs or symptoms of JHR.

References

• [3] Feb 15, 2023 — Tick-borne relapsing fever · Tetracycline 500 mg PO every 6 hours for 7-10 days · Doxycycline 100 mg PO twice daily for 7-10 days
• [4] Feb 15, 2023 — Tick-borne relapsing fever · Tetracycline 500 mg PO every 6 hours for 7-10 days · Doxycycline 100 mg PO twice daily for 7-10 days
• [5] by T Hasin · 2006 · Cited by 83 — Treatment with doxycycline is safe and efficacious in preventing TBRF after suspected exposure to ticks in a high-risk environment.
• [6] May 15, 2024 — LBRF has been successfully treated with a single dose of antibiotics. However, using a combination of penicillin and doxycycline or azithromycin for a longer duration has also been used.
• [7] by Y Binenbaum · 2019 · Cited by 12 — Post-exposure prophylaxis (PEP) with doxycycline for 5 days has been recommended to prevent TBRF after suspected exposure to ticks in high-risk environments.
• [9] by Dworkin MS, Schwan TG, Anderson DE, et al. · 2008 · Cited by 22 — The risk of Jarisch-Herxheimer reaction (JHR) appears to be lower in TBRF, but it can still occur.

The differential diagnosis of tick-borne relapsing fever (TBRF) involves a range of conditions that can present with similar symptoms, making it essential to consider multiple possibilities when diagnosing this disease.

Conditions to Consider:

• Lyme arthritis: A bacterial infection caused by Borrelia burgdorferi, which can cause fever, headache, and joint pain.
• Malaria: A mosquito-borne illness caused by Plasmodium parasites, which can lead to fever, chills, and flu-like symptoms.
• Dengue: A viral infection transmitted by mosquitoes, characterized by high fever, severe headache, and muscle pain.
• Yellow fever: A viral disease spread by mosquitoes, causing fever, chills, and liver damage.
• Leptospirosis: A bacterial infection caused by Leptospira bacteria, which can lead to fever, headache, and muscle aches.
• Typhus: A bacterial infection caused by Rickettsia bacteria, characterized by high fever, headache, and rash.
• Influenza: A viral respiratory illness that can cause fever, cough, and body aches.
• Enteric fevers: Bacterial infections of the intestines, such as typhoid fever, which can lead to fever, abdominal pain, and diarrhea.

Key Points to Consider:

• The prognosis for TBRF is generally better than for other tick-borne illnesses, with a case fatality rate of 10% for untreated patients and 2% for treated patients [13].
• The clinical manifestations of Lyme disease (LD) are shared with TBRF caused by a different group of Borrelia species termed relapsing fever Borreliae (RFB), highlighting the importance of accurate diagnosis [14].

References:

[1] - A handout on tick-borne relapsing fever, written by the authors of this article, is provided on page 2046. [2] - The differential diagnosis includes Lyme arthritis, malaria, dengue, yellow fever, leptospi