Borreliaceae

The Borreliaceae are a family of bacteria within the order Spirochaetales. This family includes the genus Borrelia, which is known for containing species that cause Lyme disease and relapsing fever in humans. Members of this family are characterized by their spiral shape and motility, which is facilitated by axial filaments.

Characteristics

Borreliaceae are Gram-negative bacteria, meaning they do not retain the crystal violet stain used in the Gram staining method of bacterial differentiation. They are distinguished by their unique spiral shape, which is typical of the phylum Spirochaetes. These bacteria are motile, using axial filaments that run along the length of the cell between the inner and outer membranes, allowing them to move in a corkscrew motion.

Genus Borrelia

The genus Borrelia is the most well-known within the Borreliaceae family. It includes several pathogenic species:

• Borrelia burgdorferi - the primary causative agent of Lyme disease in North America.
• Borrelia afzelii and Borrelia garinii - associated with Lyme disease in Europe and Asia.
• Borrelia recurrentis - responsible for louse-borne relapsing fever.
• Borrelia hermsii - a cause of tick-borne relapsing fever.

Pathogenicity

Species of Borrelia are transmitted to humans through the bites of infected ticks or lice. Once in the human body, these bacteria can evade the immune system and cause a range of symptoms. Lyme disease, for example, is characterized by an initial erythema migrans rash, followed by symptoms such as fever, headache, fatigue, and, if untreated, can lead to more severe complications affecting the joints, heart, and nervous system.

Diagnosis and Treatment

Diagnosis of infections caused by Borreliaceae typically involves serological tests to detect antibodies against the bacteria, as well as polymerase chain reaction (PCR) tests to identify bacterial DNA. Treatment usually involves antibiotics such as doxycycline or amoxicillin, with the choice of antibiotic and duration of treatment depending on the stage and severity of the disease.

Also see

• Lyme disease
• Relapsing fever
• Spirochaetes
• Tick-borne diseases