Louse-Borne Relapsing Fever - Causes, Symptoms, Diagnosis, and Management

Introduction:

Louse-borne relapsing fever is a vector-borne (transmitted by the bite of an infected animal or insect) disease. The disease is caused by certain bacteria belonging to the genus Borrelia. The bite of lice transmits the bacterial infection. As the name suggests, it is characterized by repeated episodes of fever. Louse-borne relapsing fever is more common in endemic areas such as Northeast Africa. The disease was recently found in Europe and Africa. Louse-borne relapsing fever is more common in areas associated with refugees, war, poverty, poor personal hygiene, overcrowding, and low socio-economic status. If the patient remains untreated, the fatality (death due to war or disease) rate of louse-borne relapsing fever is high. The disease is severe, and in 10 to 40 percent of cases, death occurs if it remains untreated.

What Are the Causes of Louse-Borne Relapsing Fever?

• Louse-borne relapsing fever is caused by the bacteria called spirochaete Borrelia recurrentis. It is a spiral-shaped bacteria transmitted from one human to another by the bite of a louse.

• Borrelia reccurentis enter the human body through damaged skin or bites. Still, it can also enter through intact skin or mucosa, but it does not transmit disease through intact skin.

• The louse transmits the infection. The name of the louse is Pediculus humanus corporis and Pediculus humanus capitis.

• Borrelia recurrentis has a linear chromosome and five to six plasmids. The bacteria is spiral-shaped, 8 to 30 um (micrometer) long, and 0.2 to 0.5 um in diameter. The bacteria have 8 to 30 motile flagella.

What Is the Mode of Transmission of Louse-Borne Relapsing Fever?

The mode of transmission of louse-borne relapsing fever is described as follows.

• Borrelia recurrentis is the bacteria that causes the disease. The disease is transmitted from one human to another by the body louse known as Pediculus humanus corporis, and the head lice are Pediculus humanus capitis.

• In infected humans, the body louse will ingest the Borrelia recurrentis. The spirochaetes released from the Borrelia recurrentis survive in the louse midgut. Then the spirochaetes move into the hemocoel (the body cavity of an insect contains fluid), where they multiply.

• From the sixth day after an infective blood meal, the spirochaetes become available in large quantities in the hemocoel. The transmission occurs after the crushing of the louse. The infected hemocoel is released onto the human skin.

• After the transmission, the death of the louse occurs. Hence, only one louse can infect only one person. So louse-borne relapsing fever is more common in areas with high louse density.

• The mature body louse will live for 20 to 30 days.

Who Are at Risk of Louse-Borne Relapsing Fever?

The disease affects all ages, races, and sex. The population who are at risk of developing louse-borne relapsing fever includes.

• Refugees.

• Civilian population disturbed by war.

• Areas where the louse density is high.

• Endemic areas (disease regularly occurring within the site).

• Poor personal hygiene.

• Overcrowding areas like prisons and camps.

• Children are sleeping on the streets.

• People are working in forest areas, farmers, and gardeners.

What Are the Signs and Symptoms of Louse-Borne Relapsing Fever?

The symptoms of louse-borne relapsing fever occur immediately when the bacteria are moving through the blood. The symptoms increase between five to seven days and decrease after the bacteria disappear from the blood. Once the bacteria multiply again, the symptoms reoccur again after some weeks. The symptoms are associated with the migrating bacteria in the blood. The onset of the symptoms is sudden. The symptoms include.

• General symptomsinclude high fever, chills, sweat, generalized malaise (feeling of discomfort or illness), sweat, headache, nausea, vomiting, arthralgia (joint stiffness), and myalgia (muscle pain).

• Cutaneous symptomsinclude conjunctival injection, scattered petechiae (red spot on skin results in bleeding), and erythematous rash.

• Cardiorespiratory symptoms include tachycardia (increased heart rate), mild tachypnea (abnormal heartbeat), and cough.

• Neurological symptoms include meningitis (inflammation of the covering of the brain), meningoencephalitis (inflammation of the brain's membranes), neuropathies (dysfunction of the peripheral nerves), and cerebral nerve palsies.

• Ocular symptoms include iritis (inflammation of the iris) and acute ophthalmitis (inflammation of the eye).

• Central Nervous System symptoms include hemorrhage (excessive discharge of blood from the blood vessels).

• Blood-tinged sputum.

• Splenomegaly (enlarged spleen) and hepatomegaly (enlarged liver).

How Is Louse-Borne Relapsing Fever Diagnosed?

The disease is diagnosed only when the bacteria are in the blood. The investigations include.

• Blood culture - The test is used to identify the spirochaetes. On stained blood film, the bacteria Borrelia recurrentis is seen. The bacteria is visible with dark field or phase contrast microscopy.

• Complete blood count testincludes low leucocyte count and thrombocytopenia (low blood platelet count).

• Serum examination shows an increased serum concentration of aminotransferases, alkaline phosphatase, and low albumin, suggesting hepatocellular damage.

• Cerebrospinal fluid shows an increase in lymphocytes and neutrophils.

• An Electrocardiograph (ECG) shows evidence of myocarditis, including prolonged QT interval, T-wave abnormality, and ST wave depression.

• Chest X-Ray is usually clear but may show pulmonary edema.

How Can Louse-Borne Relapsing Fever Be Managed?

• Louse-borne relapsing fever is treated within one to two weeks with antibiotics and improves within 24 hours. Complications and death are rare. Antibiotic treatment includes.

• Doxycycline: The dose in children is 4 mg/kg (milligram per kilogram) per single dose and 200 mg (milligram) per single dose in adults.

• Erythromycin: The dose in children under five years is 250 mg per single dose; for children five years and above and adults, 500 mg per single dose.

• Azithromycin: The dose in children is 10mg/kg per single dose and 500 mg per single dose for adults.

• Treatment of pain and fever with Paracetamol.

• Elimination of body lice in control of epidemics.

How Can Louse-Borne Relapsing Fever Be Prevented?

There are following steps that a person should adopt to prevent the disease. The steps are as follows.

• Wearing full cover clothes for arms and legs when a person goes outdoors.

• People should use insect repellents.

• People should wash their clothes daily.

• Clean the bed daily.

• Avoid traveling to disease-prone areas.

Conclusion:

Louse-borne relapsing fever is a bacterial infection. People should adopt preventive measures to eliminate the disease. The healthcare team, including nurses, pharmacists, and doctors, can work together to educate people about the importance of the disease and treatment. The doctor can monitor the patient and direct the treatment. The healthcare team must organize camps to inform the people about the disease and prevention and work together to achieve a better outcome.