Relapsing Fever: Symptoms, Treatments, Medications and Prevention

by topschoolsintheusa · Published October 12, 2024 · Updated September 14, 2024

Relapsing fever is an infectious disease caused by certain species of the Borrelia bacterium. The disease is characterized by recurring episodes of fever, headache, muscle pain, and other flu-like symptoms. Relapsing fever is transmitted to humans either through tick bites or lice, with the disease classified into two major forms: tick-borne relapsing fever (TBRF) and louse-borne relapsing fever (LBRF). While TBRF is more common and found in various parts of the world, LBRF tends to occur in regions with poor living conditions, particularly during periods of war and famine.

What is Relapsing Fever?

Relapsing fever is an acute febrile illness caused by Borrelia bacteria. The disease is named for its characteristic pattern of relapsing episodes of fever, where periods of high fever alternate with afebrile (fever-free) intervals. The fever typically recurs in cycles, with each episode lasting for several days, followed by a period of apparent recovery before the fever reappears.

Causative Agents of Relapsing Fever

There are two main types of relapsing fever based on the mode of transmission:

Tick-Borne Relapsing Fever (TBRF): Caused by various species of Borrelia, particularly Borrelia hermsii and Borrelia duttonii. TBRF is transmitted to humans through the bite of infected soft ticks of the genus Ornithodoros. TBRF is more geographically widespread and can be found in many regions, including parts of Africa, North America, and Asia.
Louse-Borne Relapsing Fever (LBRF): Caused by Borrelia recurrentis and transmitted through the body louse (Pediculus humanus corporis). LBRF is generally found in areas with poor sanitation and overcrowded conditions, such as refugee camps or areas affected by war or famine. It tends to cause more severe disease compared to TBRF.

How Relapsing Fever is Transmitted

The mode of transmission for relapsing fever depends on whether it is the tick-borne or louse-borne form:

Tick-Borne Relapsing Fever (TBRF): The bacteria are transmitted to humans when they are bitten by infected soft ticks. These ticks live in rodent nests, caves, and rural buildings, and they tend to feed on humans during the night. The bite is painless, and most people are unaware that they have been bitten. Unlike other tick-borne diseases, the transmission of TBRF can occur quickly, often within minutes of the tick bite.
Louse-Borne Relapsing Fever (LBRF): The transmission of LBRF occurs when infected body lice (Pediculus humanus corporis) release Borrelia recurrentis bacteria in their feces. When a person scratches the area of a louse bite, the bacteria enter the bloodstream through the broken skin. LBRF is closely associated with poor hygiene and overcrowded conditions, making it common in war zones, refugee camps, and areas affected by famine.

Once inside the human body, the Borrelia bacteria multiply in the bloodstream, causing the cycles of fever and other systemic symptoms.

Who is at Risk of Relapsing Fever?

The risk of contracting relapsing fever depends on several factors, including geographic location, living conditions, and specific activities that may lead to exposure to infected ticks or lice.

High-Risk Populations

1. People Living in Endemic Areas

Individuals who live in regions where relapsing fever is endemic are at a higher risk of contracting the disease. TBRF is found in parts of Africa, North America, Asia, and Europe, while LBRF is more common in East Africa, Ethiopia, Sudan, and Somalia.

2. Outdoor Workers and Travelers

People who work or spend time outdoors in rural or forested areas where soft ticks and rodents are common are at increased risk of exposure to TBRF. This includes:

Hikers, campers, and outdoor enthusiasts who may come into contact with tick habitats, such as rodent burrows or caves.
Farmers, foresters, and construction workers who work in rural environments with a high prevalence of soft ticks.
Travelers to areas where relapsing fever is endemic, especially if they stay in rural accommodations or shelters where ticks may be present.

3. Refugees and Displaced Populations

LBRF is often associated with poor living conditions, overcrowding, and inadequate hygiene, making refugees, displaced populations, and people living in camps more vulnerable to the disease. Outbreaks of LBRF are common in settings where people are forced to live in close quarters with limited access to clean water, sanitation, and healthcare.

4. People Living in Poverty or Conflict Zones

LBRF outbreaks tend to occur during periods of war, famine, and social disruption. People living in conflict zones or areas affected by natural disasters are at higher risk due to the breakdown of infrastructure, lack of sanitation, and increased prevalence of lice infestations.

5. People in Rodent-Infested Areas

TBRF is often associated with areas where rodents and their soft tick vectors are abundant. Individuals who live in rodent-infested environments, particularly in rural or mountainous regions, are at increased risk of exposure to infected ticks.

Symptoms of Relapsing Fever

Relapsing fever is characterized by repeated episodes of fever and systemic symptoms, followed by periods of apparent recovery. These symptoms can range from mild to severe, and the severity may depend on the specific species of Borrelia and the patient’s overall health.

Early Symptoms

The symptoms of relapsing fever typically develop 3 to 10 days after exposure to the bacteria. The onset of symptoms is often sudden, and the first episode of fever may last for several days before resolving spontaneously.

1. High Fever

A sudden onset of high fever (often reaching 39°C to 40°C or 102°F to 104°F) is the hallmark symptom of relapsing fever. The fever may last for 3 to 7 days before disappearing abruptly, only to return after a few days of being fever-free.

2. Chills and Sweats

Patients often experience intense chills at the onset of the fever, followed by profuse sweating as the fever subsides. These symptoms are part of the cyclical nature of the disease.

3. Severe Headache

Severe, throbbing headaches are common during fever episodes. The headaches may persist throughout the febrile period.

4. Muscle Aches (Myalgia)

Muscle aches and joint pain (arthralgia) are frequent symptoms of relapsing fever. These symptoms can be severe and debilitating during fever episodes.

5. Nausea and Vomiting

Gastrointestinal symptoms such as nausea, vomiting, and abdominal discomfort are common, particularly during the early stages of the disease.

6. Fatigue and Weakness

People with relapsing fever often experience extreme fatigue and weakness, which may persist even during the afebrile periods between episodes of fever.

Relapsing Episodes

After the initial fever subsides, patients typically experience a period of remission (afebrile interval) lasting 4 to 10 days. During this time, symptoms may disappear completely, and the person may feel well. However, the fever returns in a relapsing pattern, with each episode typically shorter and milder than the previous one.

Patients may experience 3 to 10 cycles of relapsing fever, depending on the type of relapsing fever (TBRF or LBRF) and whether treatment is initiated.
During each relapse, the fever and systemic symptoms recur, followed by another afebrile period.

Severe Symptoms and Complications

In severe cases of relapsing fever, particularly LBRF, complications can arise. These complications are more likely in untreated cases or in individuals with compromised immune systems.

1. Neurological Symptoms

In some cases, relapsing fever can affect the nervous system, leading to neurological symptoms such as confusion, seizures, and even coma. Meningitis and encephalitis (inflammation of the brain) are potential complications of severe relapsing fever.

2. Respiratory Symptoms

Respiratory distress, including cough and shortness of breath, may occur in severe cases, particularly in patients with pneumonia or pleuritis (inflammation of the lining around the lungs).

3. Jaundice and Liver Dysfunction

Relapsing fever can affect the liver, leading to jaundice (yellowing of the skin and eyes) and elevated liver enzyme levels. Hepatomegaly (enlarged liver) may also occur.

4. Splenomegaly

The spleen may become enlarged (splenomegaly) as a result of the body’s immune response to the infection.

5. Bleeding Disorders

In some cases, relapsing fever can cause bleeding complications, such as nosebleeds, gum bleeding, or petechiae (small red or purple spots caused by bleeding under the skin). This is due to low platelet counts (thrombocytopenia) and coagulation abnormalities.

6. Death (Rare)

In untreated cases of LBRF, particularly in malnourished or immunocompromised individuals, the mortality rate can be as high as 40%. Death usually occurs due to complications such as multi-organ failure, severe bleeding, or secondary bacterial infections.

Diagnosis of Relapsing Fever

Diagnosing relapsing fever can be challenging because its symptoms overlap with those of other febrile illnesses, such as malaria, typhoid fever, and leptospirosis. A combination of clinical evaluation, patient history, and laboratory tests is used to confirm the diagnosis.

Clinical Evaluation

The first step in diagnosing relapsing fever is a detailed clinical evaluation. Healthcare providers will ask about the patient’s symptoms, travel history, and possible exposure to ticks or lice. Key clinical signs, such as repeated episodes of high fever, chills, and muscle pain, should raise suspicion for relapsing fever, especially in people who have traveled to or live in endemic areas.

Laboratory Tests for Relapsing Fever

Several laboratory tests can confirm the diagnosis of relapsing fever and detect the presence of Borrelia bacteria.

1. Blood Smear (Microscopy)

A blood smear is the most common method for diagnosing relapsing fever. During a febrile episode, a sample of the patient’s blood is taken and examined under a microscope to detect the presence of Borrelia spirochetes (the corkscrew-shaped bacteria responsible for the disease).

Advantages: Blood smear microscopy can provide a definitive diagnosis by directly visualizing the bacteria in the bloodstream.
Disadvantages: The bacteria are often present only during the fever episodes, so timing the blood sample correctly is crucial. In the afebrile periods, the bacteria may not be detectable.

2. Polymerase Chain Reaction (PCR)

PCR is a molecular diagnostic technique that can detect the DNA of Borrelia bacteria in blood samples. PCR is more sensitive than microscopy and can confirm the diagnosis even when the bacterial load is low.

Advantages: PCR can detect Borrelia DNA during both febrile and afebrile periods, making it a more reliable diagnostic tool than blood smear microscopy.
Disadvantages: PCR testing is not always available in all regions and requires specialized laboratory equipment.

3. Serological Testing

Serological tests can detect antibodies produced by the immune system in response to Borrelia infection. However, these tests are less useful for diagnosing relapsing fever because antibody production may be delayed, and cross-reactivity with other bacterial infections can occur.

Advantages: Useful for confirming the diagnosis in the later stages of the disease.
Disadvantages: Antibodies may not be detectable in the early stages of infection, and false positives may occur due to cross-reactivity with other spirochetes.

4. Culture

In some cases, the Borrelia bacteria can be cultured from blood samples. However, this method is rarely used in routine clinical practice because it is time-consuming and requires specialized laboratory conditions.

Differential Diagnosis

Because the symptoms of relapsing fever are non-specific and resemble those of other febrile illnesses, healthcare providers must rule out other potential causes, such as:

Malaria
Typhoid fever
Leptospirosis
Dengue fever
Other tick-borne diseases (e.g., Lyme disease)

Accurate diagnosis is essential for initiating the correct treatment and preventing complications.

Treatments for Relapsing Fever

Relapsing fever is a treatable disease, and antibiotics are the mainstay of treatment. The key to successful treatment is early diagnosis and the prompt initiation of appropriate antibiotic therapy. When treated correctly, the prognosis is excellent, with most patients recovering fully within a few days.

Antibiotic Therapy

Antibiotic therapy is the cornerstone of treatment for relapsing fever, and it is highly effective in eradicating Borrelia bacteria from the bloodstream.

1. Tetracyclines (Doxycycline)

Doxycycline, a tetracycline antibiotic, is the first-line treatment for both tick-borne and louse-borne relapsing fever. It is highly effective at killing Borrelia bacteria and is typically administered orally.

Dosage for Adults: 100 mg twice daily for 7 to 10 days.
Dosage for Children: In children weighing less than 45 kg (100 lbs), the dose is 2.2 mg/kg body weight twice daily.
Mechanism of Action: Doxycycline inhibits bacterial protein synthesis by binding to the bacterial ribosome, preventing the bacteria from growing and replicating.
Efficacy: Doxycycline is highly effective, and most patients show rapid improvement within 48 hours of starting treatment.
Side Effects: Common side effects include nausea, vomiting, and photosensitivity. Doxycycline is not recommended for children under 8 years old or pregnant women due to the risk of tooth discoloration and bone development issues in children.

2. Penicillins (Benzylpenicillin or Ampicillin)

Penicillin-based antibiotics such as benzylpenicillin or ampicillin are often used to treat relapsing fever, particularly in pregnant women and young children who cannot take tetracyclines.

Dosage: Intravenous benzylpenicillin or oral ampicillin can be used, depending on the severity of the infection and the patient’s condition.
Mechanism of Action: Penicillins work by inhibiting bacterial cell wall synthesis, leading to bacterial cell death.
Efficacy: Penicillins are effective against Borrelia bacteria, though they may require longer treatment courses compared to doxycycline.

3. Macrolides (Erythromycin or Azithromycin)

Macrolide antibiotics, such as erythromycin or azithromycin, can be used as alternative treatments for relapsing fever, particularly in patients who cannot tolerate tetracyclines or penicillins.

Dosage: Erythromycin is typically administered at 250 mg four times daily, while azithromycin can be given as a single dose of 500 mg daily for 5 days.
Mechanism of Action: Macrolides inhibit bacterial protein synthesis by binding to the bacterial ribosome.
Efficacy: Macrolides are generally less effective than tetracyclines but may be useful in patients with contraindications to other antibiotics.

Jarisch-Herxheimer Reaction

One common complication of treating relapsing fever with antibiotics is the Jarisch-Herxheimer reaction, a systemic inflammatory response that occurs when large numbers of bacteria are killed and release toxins into the bloodstream.

Symptoms: The reaction typically manifests as a sudden worsening of symptoms, including fever, chills, headache, muscle pain, and low blood pressure. It usually occurs within hours of starting antibiotic treatment.
Management: The Jarisch-Herxheimer reaction is usually self-limiting and resolves within 24 to 48 hours. Supportive care, such as antipyretics (acetaminophen or ibuprofen) and intravenous fluids, may be required to manage symptoms.

Supportive Care

In addition to antibiotics, supportive care is often necessary to manage symptoms and prevent complications. Supportive care measures may include:

Antipyretics: Medications such as acetaminophen or ibuprofen can be used to reduce fever and alleviate pain.
Hydration: Ensuring adequate hydration is important, especially in patients with severe vomiting or dehydration.
Hospitalization: In severe cases, hospitalization may be required to manage complications such as respiratory distress, multi-organ failure, or neurological involvement.

Duration of Treatment

The standard duration of antibiotic treatment for relapsing fever is 7 to 10 days. It is important to complete the full course of antibiotics even if symptoms improve early, as this ensures the infection is fully eradicated and reduces the risk of relapse.

Common Medications for Relapsing Fever

Several antibiotics are commonly used to treat relapsing fever, depending on the type of infection and the patient’s overall health. Doxycycline is the most frequently prescribed medication, but alternatives are available for patients who cannot take tetracyclines.

1. Doxycycline

Doxycycline is the first-line treatment for both tick-borne and louse-borne relapsing fever due to its high efficacy and rapid action.

How It Works: Doxycycline inhibits bacterial protein synthesis by binding to the bacterial ribosome, preventing the bacteria from growing and replicating.
Dosage: 100 mg twice daily for 7 to 10 days for adults. In children under 45 kg, the dose is 2.2 mg/kg twice daily.
Side Effects: Common side effects include nausea, vomiting, photosensitivity, and, in some cases, esophagitis.

2. Penicillin (Benzylpenicillin or Ampicillin)

Penicillin-based antibiotics are often used as an alternative to doxycycline in pregnant women and young children.

How It Works: Penicillins inhibit bacterial cell wall synthesis, leading to bacterial cell death.
Dosage: Intravenous benzylpenicillin or oral ampicillin can be used, depending on the patient’s condition.
Side Effects: Common side effects include allergic reactions, diarrhea, and gastrointestinal discomfort.

3. Erythromycin or Azithromycin

Macrolide antibiotics, such as erythromycin or azithromycin, are used as alternatives in patients who cannot tolerate tetracyclines or penicillins.

How It Works: Macrolides inhibit bacterial protein synthesis by binding to the bacterial ribosome.
Dosage: Erythromycin is typically given at 250 mg four times daily, while azithromycin is given as 500 mg once daily for 5 days.
Side Effects: Common side effects include gastrointestinal symptoms, such as nausea and diarrhea.

Where is Relapsing Fever Most Prevalent?

Relapsing fever is found in various parts of the world, with the geographical distribution of the disease depending on the specific type (tick-borne or louse-borne) and the vector involved.

Geographic Distribution

1. Africa

Relapsing fever is endemic in several African countries, particularly in East Africa and North Africa. Louse-borne relapsing fever (LBRF) is more common in areas with poor sanitation and overcrowding, while tick-borne relapsing fever (TBRF) is found in rural and mountainous regions.

Ethiopia, Sudan, Somalia, and Eritrea: These countries have reported outbreaks of LBRF, particularly in conflict zones and refugee camps.
Tanzania, Kenya, and Uganda: TBRF is more common in rural areas where soft ticks and rodent populations are abundant.

2. North America

Tick-borne relapsing fever (TBRF) is found in parts of the United States, particularly in the western states, including:

California, Colorado, Idaho, Washington, and Texas: These states have reported cases of TBRF, particularly in rural and mountainous areas where rodent populations are high.

3. Europe

TBRF is rare in Europe but has been reported in Spain and Portugal, where soft ticks are known to inhabit rural areas.

4. Asia

Relapsing fever is found in several parts of Asia, particularly in Iran, Turkey, and Afghanistan. Both TBRF and LBRF have been reported in these regions, with outbreaks linked to poor living conditions and rodent infestations.

Prevention of Relapsing Fever

Preventing relapsing fever involves reducing exposure to the vectors that transmit the disease—ticks and lice—and improving public health measures, especially in areas prone to outbreaks.

Personal Protective Measures

Individuals living in or traveling to areas where relapsing fever is endemic can reduce their risk of infection by taking personal protective measures.

1. Avoiding Tick Habitats

To prevent TBRF, individuals should avoid areas where soft ticks are likely to be found, such as rodent burrows, caves, and rural buildings. People who spend time outdoors in these environments should take the following precautions:

Wearing Protective Clothing: Long-sleeved shirts, long pants, and closed-toe shoes can help prevent tick bites. Tucking pants into socks and wearing gloves can provide additional protection.
Using Insect Repellents: Insect repellents containing DEET or permethrin can be applied to clothing and exposed skin to repel ticks.

2. Preventing Louse Infestation

To prevent LBRF, individuals should avoid overcrowded and unsanitary living conditions that promote louse infestations. Measures to prevent lice infestations include:

Good Personal Hygiene: Regular bathing and washing clothes in hot water can help prevent lice infestations.
Louse Control: In areas with known outbreaks of LBRF, louse control measures, such as insecticidal powders or shampoos, can be used to eliminate lice from clothing and bedding.

Environmental Control Measures

Controlling the environment and reducing rodent populations can help prevent the spread of TBRF.

1. Rodent Control

Reducing the population of rodents, which serve as the natural hosts for soft ticks, is important for preventing TBRF. Measures include:

Trapping and Extermination: Using traps and rodenticides to control rodent populations in and around homes and workplaces.
Improved Sanitation: Reducing access to food waste and improving waste management practices to decrease the rodent population.

2. Tick Control

Controlling soft tick populations in endemic areas is essential for preventing the spread of TBRF. This can be achieved through:

Insecticides: Applying insecticides to rodent nests and other areas where soft ticks are known to live can reduce tick populations.

Public Health Education

Public health education plays a critical role in preventing relapsing fever by raising awareness of the risks associated with tick and louse exposure.

1. Community Education Campaigns

Community education campaigns can inform people about the dangers of relapsing fever, how it is transmitted, and how to avoid exposure to ticks and lice. These campaigns should target high-risk populations, such as outdoor workers, travelers, and people living in refugee camps or conflict zones.

2. Training Healthcare Workers

Healthcare workers in endemic regions should be trained to recognize the early signs and symptoms of relapsing fever and provide prompt treatment. Early diagnosis and treatment are crucial for preventing complications and reducing the burden of the disease.