What Is Louse-Borne Relapsing Fever (LBRF)?

Medically Reviewed by Dany Paul Baby, MD on October 18, 2022
Written by Mallika Bhattacharya
4 min read

Louse-borne relapsing fever (LBRF) is a severe bacterial infection. You can get it from a body louse that has sucked the blood of an infected person. As the name suggests, the most common symptom of LBRF is getting a fever repeatedly. If you encounter this type of illness, make sure to seek treatment immediately.

Louse-borne relapsing fever is a vector-borne disease caused by the spiral-shaped bacteria Borrelia recurrentis. This disease, along with other relapsing fevers like tick-borne relapsing fever (TBRF), is caused by bacterial species belonging to the Borrelia family.

LBRF is typically transmitted by the human body louse Pediculus humanus corporis and maybe also by the head louse P. humanus capitis, though transmission by head lice has not been proven. However, the latter is yet to be confirmed. Studies have found Louse-borne relapsing fever to be fatal in 10% to 40% of cases when the patients are not treated. When treatment is given, loss of life is seen in 2% to 5% of the cases.

LBRF-causing bacteria enter and multiply inside the louse once the latter takes blood from an infected person. Note that you won't get this disease even if such an infected louse bites you. Rather, the bacteria inside the lice would have to enter through a break in your skin for you to get infected. This could happen if you scratch a bite and crush the infected lice by mistake, releasing their body fluids onto your skin. Once the bacteria enter your body, they could multiply in your bloodstream and within other organs like the liver, brain, and spleen.

Louse-borne recurring fever has been known to cause many epidemics. It usually occurred and still does when conditions suitable for the spread of body lice are met. Those who live in such conditions mostly include slum dwellers, refugees, famine survivors, and prisoners of war. Their living spaces are overcrowded, poorly maintained, and unhygienic — all helping lice to spread.

Historically, the largest LBRF outbreaks occurred in Africa and Eastern Europe. For example, a million cases were seen in North Africa during World War II. With living standards improving over the world, though, the spread of this disease has decreased drastically. Today, it's mostly seen in the poor localities of countries like Ethiopia, Sudan, Somalia, northern China, and Peru.

The symptoms of louse-born recurring fever usually occur suddenly while the bacteria are moving through the blood. The intensity of the symptoms increases during the next five days — usually from day 5 to day 7 — and gradually reduces as the bacteria start to disappear from the blood. Once the bacteria proliferate again, sometimes weeks later, the symptoms return. Usually, less than 10 such relapses occur, even without treatment.

The most distinct symptom of LBRF is a sudden fever, which usually occurs either during the first or second week of infection. The fever lasts anywhere between 3 to 6 days. Often, a single episode of milder fever follows this period of sudden fever. Every time the fever episode ends, you may face a "crisis" — a condition characterized by:

  • Shaking chills
  • Falling body temperature
  • Intense sweating
  • Falling blood pressure

In severe, untreated cases, the "crisis" period can lead to a coma or death.

Other symptoms of louse-born recurring fever may include:

  • Headaches
  • Nausea and vomiting
  • Stiff neck
  • Muscle and joint pain
  • Bleeding 
  • Jaundice
  • Weakness 

Medical experts might suspect that you have a louse-borne recurring fever if you come from a high-risk area and have a high fever, don't respond well to antimalarial medicines, and experience.

  • Chills
  • Jaundice
  • Joint ache

A doctor may also recommend some or all of these tests to confirm if you are infected with the LBRF bacteria:

  • Borrelia bacteria can be identified using your blood smear or stained blood films, typically during the phase where the bacteria are moving through your blood. Tests can be carried out to identify the genetic material of the bacteria in your blood and support clinical test findings.
  • In some cases, blood antibody tests can also be performed. However, their effectiveness may be limited.

Doctors usually prescribe antibiotics for suspected and confirmed cases of louse-borne recurring fever. While most cases can be cured by a single dose of antibiotics, your healthcare provider may suggest a longer course of treatment to prevent the disease from returning.

The type of drugs prescribed (such as Doxycycline, Erythromycin, penicillins, and tetracyclines), as well as their dosage, will differ based on the patient and their condition. The doctor may prescribe paracetamol (PO) for fever as well as medications for diarrhea and pain if required. Medical experts will also take steps to help you get rid of body lice.

Before taking the treatment for louse-borne relapsing fever, keep in mind that there is a chance of the potentially fatal Jarisch–Herxheimer reaction occurring. For this reason, your doctor may prefer to monitor you closely to look for any possible symptoms of this reaction. If you experience a high fever, tension, confusion, or anxiety followed by excessive sweating and a fall in temperature, you should let the doctors know immediately.

Avoid becoming infested with lice to prevent louse-borne relapsing fever from occurring. Besides direct contact with an infected person, you can also catch lice from infested bedding and clothing. Make sure to regularly bathe and wash your clothes and bedding.

If your surroundings have already been infested, discard your infected clothes. If that's not possible, wash them at a temperature of 60 degrees Celsius or higher. In the case of an outbreak, trained personnel may also treat your clothes with an insecticide like DDT or 0.5% permethrin dust.

Louse-born recovering fever can be fatal if left untreated. Talk to a doctor immediately if you develop a fever and "crisis" period symptoms, especially if you have been exposed to conditions that promote lice infestation.