Borrelia turicatae

Relapsing Fever Borrelia

Borrelia turicatae is a relapsing fever Borrelia, as oppposed to the more widely known Borrelia burgdorferi (Lyme disease) that isn't relapsing.

The 2019 study linked below indicates when testing the two different types of Borrelia there can be a cross-reaction so you don't know what organism is actually infecting you.

In humans and animals the two are treated differently, making this situation a sincere concern.

QUOTE- "In this study, B. burgdorferi-negative dogs were inoculated with B. turicatae and seroconversion was confirmed by the rBipA Western blot.

Seropositive samples were tested with commercial and veterinary diagnostic laboratory B. burgdorferi-based tests.

Borrelia turicatae-seroreactive samples cross-reacted with a whole cell IFA and two multi-antigen tests; but not with single antigen tests using C6."

Link to Study


The CDC reports (take with a grain of salt)... "Findings on physical exam vary depending on the severity of illness and when the patient seeks medical care.

Regardless, there are no findings specific for TBRF. Patients typically appear moderately ill and may be dehydrated.

Occasionally a macular rash or scattered petechiae may be present on the trunk and extremities.

Less frequently, patients may have jaundice, hepatosplenomegaly, meningismus, and photophobia (Table 1). Although less common, infection with B. turicatae is especially likely to result in neurologic involvement."

Table 1. Selected Symptoms and Signs among Patients with Tick-borne Relapsing Fever, United States*

*Abstracted from Dworkin, M. S., et al. Tick-borne relapsing fever in the northwestern United States and southwestern Canada. Clinical Infectious Diseases 1998; 26: 122-31.

CDC Information for Clinicians


Relapsing Fever Bacteria

Relapsing fever is caused by certain species of Borrelia, a gram negative bacteria 0.2 to 0.5 microns in width and 5 to 20 microns in length.

They are visible with light microscopy and have the cork-screw shape typical of all spirochetes.

Relapsing fever spirochetes have a unique process of DNA rearrangement that allows them to periodically change the molecules on their outer surface.

This process, called antigenic variation, allows the spirochete to evade the host immune system and cause relapsing episodes of fever and other symptoms.

Three species cause TBRF in the United States: Borrelia hermsii, B. parkerii, and B. turicatae. The most common cause is cause is B. hermsii.

Tick-borne relapsing fever is characterized by recurring febrile episodes that last ~3 days and are separated by afebrile periods of ~7 days duration.

Along with fever, patients may experience a wide range of nonspecific symptoms (Table 1).

Each febrile episode ends with a sequence of symptoms collectively known as a “crisis.”

During the “chill phase” of the crisis, patients develop very high fever (up to 106.7°F or 41.5°C) and may become delirious, agitated, tachycardic and tachypneic.

Duration is 10 to 30 minutes. This phase is followed by the “flush phase”, characterized by drenching sweats and a rapid decrease in body temperature.

During the flush phase, patients may become transiently hypotensive. Overall, patients who are not treated will experience several episodes of fever before illness resolves.


Spirochetemia (spirochetes in blood) in TBRF patients often reaches high concentrations (>106 spirochetes/ml). Thus, microscopy is a useful diagnostic tool for TBRF.

The diagnosis of TBRF may be based on direct microscopic observation of relapsing fever spirochetes using dark field microscopy or stained peripheral blood smears.

Spirochetes are more readily detected by microscopy in symptomatic, untreated patients early in the course of infection.

Other bacteria, such as Helicobacter, may appear morphologically similar, so it is important to consider clinical and geographical characteristics of the case when making a diagnosis of TBRF based on microscopy.

Additional testing, such as serology or culture, is recommended.

Serologic testing for TBRF is not standardized and results may vary by laboratory.

Serum taken early in infection may be negative, so it is important to also obtain a serum sample during the convalescent period (at least 21 days after symptom onset).

A change in serology results from negative to positive, or the development of an IgG response in the convalescent sample, is supportive of a TBRF diagnosis.

However, early antibiotic treatment may limit the antibody response. Patients with TBRF may have false-positive tests for Lyme disease because of the similarity of proteins between the causative organisms.

A diagnosis of TBRF should be considered for patients with positive Lyme disease serology who have not been in areas endemic for Lyme disease.

Speciation of the relapsing fever Borrelia is typically not done in absence of a culture. The Borrelia species is often inferred from the location of the patient’s exposure.

If the exposure occurred in a western state, at high elevation (1200-8000 feet), TBRF is usually due to Borrelia hermsii.

If the exposure occurred in a southern state, specifically Texas or Florida, at lower elevation, TBRF is usually due to Borrelia turicatae.

Incidental laboratory findings include normal to increased white blood cell count with a left shift towards immature cells, a mildly increased serum bilirubin level, mild to moderate thrombocytopenia, elevated erythrocyte sedimentation rate (ESR), and slightly prolonged prothrombin time (PT) and partial thromboplastin time (PTT).

CDC Recommendations

Treatment of Tick-borne Relapsing Fever

TBRF spirochetes are susceptible to penicillin and other beta-lactam antimicrobials, as well as tetracyclines, macrolides, and possibly fluoroquinolones.

CDC has not developed specific treatment guidelines for TBRF; however, experts generally recommend tetracycline 500 mg every 6 hours for 10 days as the preferred oral regimen for adults.

Erythromycin, 500 mg (or 12.5 mg/kg) every 6 hours for 10 days is an effective alternative when tetracyclines are contraindicated.

Parenteral therapy with ceftriaxone 2 grams per day for 10-14 days is preferred for patients with central nervous system involvement, similar to early neurologic Lyme disease.

In contrast to TBRF, LBRF caused by B. recurrentis can be treated effectively with a single dose of antibiotics.

When initiating antibiotic therapy, all patients should be observed during the first 4 hours of treatment for a Jarisch-Herxheimer reaction.

The reaction, a worsening of symptoms with rigors, hypotension, and high fever, occurs in over 50% of cases and may be difficult to distinguish from a febrile crisis.

Cooling blankets and appropriate use of antipyretic agents may be indicated.

In addition acute respiratory distress syndrome requiring intubation has been described recently in several patients undergoing treatment for TBRF.

CDC- Complications and Prognosis

Given appropriate treatment, most patients recover within a few days. Long-term sequelae of TBRF are rare but include iritis, uveitis, cranial nerve and other neuropathies.

Tick-borne Relapsing Fever in Pregnancy

TBRF contracted during pregnancy can cause spontaneous abortion, premature birth, and neonatal death.

The maternal-fetal transmission of Borrelia is believed to occur either transplacentally or while traversing the birth canal.

In one study, perinatal infection with TBRF was associated with lower birth weights, younger gestational age, and higher perinatal mortality (Jongen, van Roosmalen et al. 1997).

In general, pregnant women have higher spirochete loads and more severe symptoms than nonpregnant women. Higher spirochete loads have not, however, been found to correlate with fetal outcome.

CDC- Immunity

Although there is limited information on the immunity of TBRF, there have been patients who developed the disease more than once.

CDC- Public Health Reporting Requirements

Although not a nationally notifiable condition, prompt reporting of TBRF cases is currently required in at least 12 states: Arizona, California, Colorado, Idaho, Montana, North Dakota, Nevada, New Mexico, Oregon, Texas, Utah, and Washington.

Regardless of location, health care providers should report cases to appropriate state or local health authorities.

Large multistate outbreaks have been linked to rental cabins near national parks and other common vacation locations, and prompt reporting by clinicians was critical to the identification and control of these outbreaks.

Without corrective action, tick-infested cabins can remain a source of human infection for many years.

Page last reviewed: November 26, 2018

Content source: Centers for Disease Control and Prevention, Centers for Disease Control and Prevention National Center for Emerging and Zoonotic Infectious Diseases (NCEZID), National Center for Emerging and Zoonotic Infectious Diseases (NCEZID) Division of Vector-Borne Diseases (DVBD) Division of Vector-Borne Diseases (DVBD)

Additional Information

CDC Map of Cases of TBRF

(They forgot all the other places it has been found- don't rely on this map.)

This CDC info is old and much of it is inaccurate, however, I am highlighting some points below that should be noted.


Borrelia bacteria that cause TBRF are transmitted to humans through the bite of infected “soft ticks” of the genus Ornithodoros.

Soft ticks differ in two important ways from the more familiar “hard ticks” (e.g., the dog tick and the deer tick).

First, the bite of soft ticks is brief, usually lasting less than half an hour.

Second, soft ticks do not search for prey in tall grass or brush. Instead, they live within rodent burrows, feeding as needed on the rodent as it sleeps.

In Cabins- The ticks emerge at night and feed briefly while the person is sleeping. The bites are painless, and most people are unaware that they have been bitten.

Between meals, the ticks may return to the nesting materials in their host burrows.

CDC Information

There are several Borrelia species that cause TBRF, and these are usually associated with specific species of ticks.

For instance, B. hermsii is transmitted by O. hermsi ticks, B. parkerii by O. parkeri ticks, and B. turicatae by O. turicata ticks.

Each tick species has a preferred habitat and preferred set of hosts:

  • Ornithodoros hermsi tends to be found at higher altitudes (1500 to 8000 feet) where it is associated primarily with ground or tree squirrels and chipmunks.
  • Ornithodoros parkeri occurs at lower altitudes, where they inhabit caves and the burrows of ground squirrels and prairie dogs, as well as those of burrowing owls.
  • Ornithodoros turicata occurs in caves and ground squirrel or prairie dog burrows in the plains regions of the Southwest, feeding off these animals and occasionally burrowing owls or other burrow- or cave-dwelling animals.

Soft ticks can live up to 10 years; in certain parts of the Russia the same tick has been found to live almost 20 years.

Individual ticks will take many blood meals during each stage of their life cycle, and some species can pass the infection along through their eggs to their offspring.

The long life span of soft ticks means that once a cabin or homestead is infested, it may remain infested unless steps are taken to find and remove the rodent nest.

Page last reviewed: October 15, 2015

Link To Page Here

If you find nests in your building that may have ticks- do not try to remove them yourself since you could expose yourself to histoplasmosis and the plague.

CDC Information

Why shouldn't I remove the nests myself?

Activities that put you in contact with deer mouse droppings, urine, saliva, or nesting materials can place you at risk for infection with Hantavirus Pulmonary Syndrome (HPS), a potentially fatal condition.

Hantavirus is spread when virus-containing particles from deer mouse urine, droppings, or saliva are stirred into the air. Infection occurs when you breathe in virus particles.

Last Updated- July 2019

Lucy Barnes