Lyme Disease, Relapsing Fever, and the Role of Borrelia

 

Introduction of borrelia

Borrelia it is spriral shaped genus of bacteria belonging to spirochete phylum. Borrelia species are members of the family spirochaetaceae. 

What is  borrelia?

Irregular spirals, highly flexible and Stain readily with bacteriologic dyes as well as with blood stains such as Giemsa or Wright stain.  Can be grow in fluid media containing blood serum or tissue. The antigenic structure of the organism changes in the course of a single infection. The relapsing course of the disease appears to be due to the multiplication of such antigenic variants.  Antibodies develop in high titter.

Types of borrelia

1. Relapsing fever group

The relapsing fever group refers to a cluster of Borrelia species that cause relapsing fever, a disease marked by repeated episodes of high fever separated by periods without fever. These bacteria are usually transmitted to humans by lice (Borrelia recurrentis) or by soft ticks (Borrelia hermsii, Borrelia duttonii, and others). The name “relapsing” comes from the pattern of illness, as the fever returns multiple times due to the bacteria’s ability to change its surface proteins and evade the immune system. This group is distinct from the Lyme disease group of Borrelia.

Relapsing fever – febrile illness characterized by recurrent episodes of fever and septicemia separated by afebrile periods. Two types:

a)  Epidemic/louse born is caused by B. recurrentis and is transmitted by human lice (pediculus humanus).

b)      Endemic/tick born – is caused by many Borrelia species (15), B.duttoni, B.hermsii and is transmitted by ticks (Orinthodoros).

2. Lyme disease

Named after the town of Lyme - a number of cases were first discovered in 1975.  Tick born disease (transmitted from mice by ticks) Involves dermatologic, rhematologic, neurologic and cardiac abnormalities. Transmitted by 10 Borrelia species and three species are associated with human disease (B. burgdorferi, B.garinii, B. afzelii). Transmitted to humans by the saliva of the tick which contaminates the site of the bite. Lyme disease should always be treated with antibiotics. Without treatment, infection can spread to large joints, the  heart, and the nervous system. 

Sign and symptoms of lyme

Early stage  

·   Unique skin lesions (rash) occurs 3-4 weeks after a tick bite

·   The lesion is a flat reddened area near the tick bite and slowly expands with central clearing

·   There is also flue like illness with fever, chills, myalgia and headache  

Late stage 

• Occurs weeks to months later

• Includes arthralgia and arthritis

• Meningitis

• Facial nerve palsy

• Painful radiculopathy

• Cardiac disease

• It might be associated with deposition of Ag-Ab complexes. 

Epidemiology of lyme disease

Mice and deer are main animal reservoirs of B.burgdorfeeri.  Most exposures are in May through July, when the lymphal stage of the ticks is most active. Prevention avoidance of exposure of ticks Long sleeves and long pants tucked in to socks are recommended.

Pathogenicity

Borrelia spreads with bloods to many organs and commonly affect spleen and liver (hepato and splenomegaly). Louse born RF is common in crowded, malnutrition, cold climate, unsanitary conditions (wars, disasters etc.). it is endemic in Ethiopia, Sudan and Rwanda.  

Diagnosis

Microscopy examination of blood is not recommended (B.bugdorfeeri rarely seen in clinical specimen) Culture:  Needs special media Serology: Is an important diagnostic method Immunofluorescence assay (IFA) and Enzyme linked immunosorbent assay (ELISA). 

Haw to treatment Lyme disease

At the early stage, doxycycline, amoxicillin, or erythromycin. In later stages, intravenous penicillin or ceftriaxone.

Haw to prevention borrelia

• Prevention is delousing, improvement of hygiene, using insect repellent and rodent control

• Tick avoidance

• Routine scanning and quick removal of ticks

• Repellents

• Vaccination

Conclusion

Borrelia species are spiral-shaped bacteria transmitted mainly by ticks and lice, causing diseases such as Lyme disease and relapsing fever. Early diagnosis and antibiotic treatment are essential to prevent severe complications.