Summary about Disease
Louse-borne relapsing fever (LBRF) is an infectious disease caused by the bacterium Borrelia recurrentis and transmitted to humans through the bite of the human body louse (*Pediculus humanus corporis*). It's characterized by recurring episodes of fever separated by periods without symptoms.
Symptoms
Sudden high fever (104-106°F or 40-41°C)
Severe headache
Muscle and joint pain (myalgia and arthralgia)
Chills and shaking
Nausea and vomiting
Abdominal pain
Cough
Jaundice (yellowing of the skin and eyes)
Petechiae (small, pinpoint-sized red or purple spots on the skin)
Enlarged liver and spleen (hepatosplenomegaly)
Neurological symptoms (e.g., confusion, seizures, coma) can occur in severe cases.
Causes
LBRF is caused by the bacterium Borrelia recurrentis. The bacteria are transmitted to humans when infected body lice are crushed or scratched into the skin, mucous membranes, or conjunctiva. The bacteria then enter the bloodstream and cause infection. Transmission does NOT typically occur through louse bites alone, but rather when the lice are crushed.
Medicine Used
Tetracycline: A common antibiotic used to treat LBRF.
Doxycycline: Another tetracycline antibiotic.
Erythromycin: Used for individuals who cannot tolerate tetracyclines (e.g., pregnant women, children under 8).
Jarisch-Herxheimer Reaction Management: Treatment often triggers this reaction (fever, chills, headache, muscle pain) which is managed with supportive care such as fluids, antipyretics (e.g., acetaminophen), and sometimes corticosteroids in severe cases.
Is Communicable
LBRF is not directly communicable from person to person. The disease is transmitted through infected body lice. A person-to-person transmission can only occur when the lice travel from one person to another.
Precautions
Personal hygiene: Regular bathing and washing clothes significantly reduce the risk of louse infestation.
Delousing: Treating clothing and bedding with insecticides to kill lice. Permethrin is a common insecticide used.
Avoid contact with infested individuals and their belongings: Minimize close contact with people who have body lice and avoid sharing clothing, bedding, or other personal items.
Public health measures: Implementing control measures in areas with outbreaks, including mass delousing campaigns.
How long does an outbreak last?
The duration of an LBRF outbreak depends on several factors, including:
Effectiveness of control measures: Prompt and effective delousing campaigns can shorten the outbreak.
Living conditions and hygiene: Overcrowding and poor sanitation contribute to the spread of lice and prolong outbreaks.
Availability of treatment: Timely diagnosis and treatment can reduce the duration and severity of illness.
Outbreaks can last from weeks to months or even longer if control measures are not effectively implemented.
How is it diagnosed?
Microscopic examination of blood: Borrelia recurrentis* can be directly observed in blood smears stained with Giemsa or Wright stain during febrile episodes. This is the most rapid method.
Dark-field microscopy: Can be used to visualize the spirochetes in blood.
PCR (Polymerase Chain Reaction): A more sensitive test to detect Borrelia recurrentis DNA in blood samples.
Serological tests: Detect antibodies against Borrelia recurrentis, but these tests may not be reliable during the early stages of infection.
Clinical presentation: The characteristic relapsing fever pattern is an important diagnostic clue, particularly in endemic areas.
Timeline of Symptoms
Incubation period: 5-15 days (time between louse exposure and onset of symptoms).
First febrile episode: Sudden onset of high fever, headache, muscle pain, and other symptoms lasting 3-6 days.
Afebrile period: Symptoms resolve for 2-9 days.
Relapse: Recurrence of fever and other symptoms, typically milder than the initial episode, lasting 1-3 days. Multiple relapses (3-10) can occur if left untreated.
Important Considerations
Jarisch-Herxheimer Reaction: This reaction commonly occurs within hours of starting antibiotic treatment and involves fever, chills, sweating, headache, muscle pain, and a temporary worsening of symptoms. It is caused by the release of toxins from dying bacteria. Management includes supportive care.
Differential diagnosis: Consider other causes of fever, especially malaria, typhoid fever, and other bacterial or viral infections.
Co-infections: Individuals with LBRF may also be infected with other pathogens, such as Rickettsia prowazekii (the cause of epidemic typhus), because both are transmitted by body lice.
Pregnant women: Tetracyclines should be avoided during pregnancy due to the risk of fetal harm. Erythromycin is often used as an alternative.
Severe complications: Untreated LBRF can lead to severe complications, including myocarditis (inflammation of the heart), neurological problems, and death.
Public Health Importance: LBRF outbreaks are often associated with conditions of poverty, overcrowding, and poor hygiene, highlighting the importance of addressing these underlying social determinants of health.