G.HARIPRASAD M.Sc.,(Med micro),M.phil.,Lecturer in Microbiology Department of Microbiology Thoothukudi Govt. Medical College Thoothukudi

Spirochaete with wide-opened coils

Stain easily with ordinary stains i.e. Gram stain

Gram negative spiral rods

Some borrelia occur as mouth commensals

Species of medical concern

• Borrelia recurrentis

Causes Relapsing fever

• Borrelia vincentii

Causes Vincent’s angina

• Borrelia burgdorferi

Causes Lyme disease

Relapsing fever

• Arthropod-borne infection

Implicated arthropod

Body Louse

Ticks

TICK

BODY LOUSE

Pathogenesis

• Infection occur when infected arthropod bites

• Incubation period – 2-10 days

• Recurrent fever (relapses) – due to antigenic variation

• 3-10 relapses can occur

• Spleenomegaly common

Laboratory diagnosis

• Blood can be examined for borrelia by the following methods

Dark ground microscopy

Giemsa or Leishman stain

Culture & serology

Animal inoculation

TREATMENT

• Tetracyclin

• Chloramphenicol

• Pencillin

• Erythromycin

Prophylaxis

Control of vectors ( louse and tick)

Maintenance of good personal hygiene

Vincent’s angina

• Borrelia vincentii cause Vincent’s angina in association with fusiform bacilli (fusobacteria)

• This symbiotic relationship called fusospirochaetosis

Predisposing factor • Poor oral hygiene• Immunosuppression

Lab diagnosis

• Exudate from gingival lesions

Direct demonstration:

• Dark ground microscopy

• Gram stain – shows

Spirochaetes

fusiform bacilli(Gram -ve rods) Fusiform rods

CULTURE

• Serum enriched media

• Incubated in anaerobic environment

Treatment:

Penicillin

Metronidazole

LYME DISEASE

Causative agent:

• Borrelia burgdorferi

First case identified in Lyme, USA – hence the name “Lyme disease”

DEER - RESERVOIR IXODID TICK

Tick gets borrelia when feed deer’s blood

BORRELIA

PATHOGENICITY

Erythema migrans – forms where tick bites

TICK FEEDING ON HUMAN

DISSEMINATED INFECTION

• Enters blood to cause symptoms like

Headache

Fever

Myalgia

Lymphadenopathy

PERSISTENT INFECTION

Develops if infection persist for years

Symptoms like

• Chronic arthritis

• Polyneuropathy

• Encephalopathy

CLINICAL MANIFESTATION

Laboratory diagnosis

BLOOD SMEAR EXAMINATION AFTER GIEMSA STAINING

DARK FIELD MICROSCOPY

FONTANA’S STAIN

Fluorescent microscopy

Borrelia-specific antibody tagged with fluorescent dyes are added

If borrelia binds with such antibodies, they can fluoresce like this!!!!!!!!!

CULTURE

• Barbour-stoenner Kelly’s (BSK) medium

• Microaerophilic

• Incubation for two weeks or more.

TREATMENT

• Tetracycline

• Penicillin

• Erythromycin

NO VACCINES !!!!!!!!!!!!