Download Lecture 27-Treponema and Borrelia

‫بسم هللا الرحمن الرحيم‬
GENERA:
TREPONEMA & BORREILIA
Prof. Khalifa Sifaw Ghenghesh
 Unicellular
helical or spiral rodshaped spirochaetes.
 Actively motile
– Flagella attached at each pole of the
cell and wrap around the bacterial
cell body
– Flagella are enclosed within the
bacterial outer membrane
Treponema
Do not stain by Gram’s method
 Pathogenic Treponema

–
–
–
–
T.
T.
T.
T.
pallidum
pertenue
endemicum
carateum
– Cannot be cultivated in laboraotry media
– Maintained by subculture in susceptible
animals
– Differentiation of organisms is based
primarily on clinical syndromes
– Micro-aerophilic
Treponema pallidum
 Syphilis
– Acquired by sexual contact with
infected person
 Congenital
Syphilis
– Infected mother to fetus in utero or
during passage of neonates through
infected canal (vertical
transmission)
PATHOGENESIS
Untreated the disease may progress
to Primary, Secondary, latent and
Tertiary stages.
 Primary syphilis

– Organism penetrates intact mucosae >
lymphatics > disseminates via blood to
any organ
– Multiplies at entry site > ~ 3 weeks >
painless chancre (mainly on external
genitalia).
– Chancre heals spontaneous in 3-6 weeks

Secondary syphilis
– Appear 2-12 weeks
– Symptoms are highly variable but mainly
involve the skin (macular or pustular
lesion)
– Lesions are highly infectious and
gradually resolve

Latent syphilis
– No clinical manifestations are seen but
serological evidence of infection remains
– Individuals are not generally infectious
but can transmit infection to the fetus
during pregnancy
– Their blood can be infectious
 Tertiary
syphilis
– May develop decades after primary
syphilis
– A slowly progressive, destructive
inflammatory disease > affects any
organ
 Neurosyphilis
 Cardiovascular
syphilis
 Gummatous syphilis
Histopathology showing Treponema
pallidum spirochetes.
Modified Steiner silver stain.
Treponema pallidum
darkfield preparation
Light microscope pictures showing
tissue infected with the spirochete
Treponema pallidum, the causative
agent of syphilis.
Treponema organisms stained by
fluorescent-tagged antibodies.
Treponema pertenue
– Yaws
– Rural population in subtropical countries
– Non-venereal, after contact of traumatized skin
with exudate from early yaws lesion
– Primary yaws (3-5 weeks) > lesions on the legs
>> papular lesions >> enlarge erode and heal
spontaneously within 6 months > may erupt
weeks or months later.
– Secondary lesions > bones (fingers, long bones
and jaw)
– Late yaws > cutaneous plaques and ulcers and
thickening of the skin on the palms and soles of
the feet.

No neurological and cardiovascular damage
– No congenital yaws
Treponema endemicum
– Bejel (endemic syphilis)
– Non-venereal, affects mainly children rural
populations in Africa, western Asia and Australia
– Direct person to person contact and by sharing
contaminated eating and drinking utensils
– Initial lesion > oral
– Secondary lesions > oropharyngeal mucous
patches, condyloma lata and periostitis
– Late lesion > gummata in the skin, nasopharynx
and bones

No neurological and cardiovascular damage
– congenital bejel is rare
Treponema carateum
 Pinta
Rural regions of Mexico, Central
America and Colombia
 Confined to the skin
 Non-destructive lesion but cause
disfigurement
 Direct contact with infectious lesions
resulting in depigmented lesions
which are characteristic of late stages
of pinta with no serious harm

LABORATORY DIGNOSIS

Direct Microscopy
– Specimen: fresh exudate from primary
or secondary lesions
– Examine with dark-ground or phase
contrast microscopy

Serological Tests
- T. pallidum infection > 2 types of Abs
– Specific Abs against polypeptide Ags of
the bacterium
– Non-specific Abs reacts with a nontreponemal Ag > Cardiolipin
1. Non-Specific Serological Test

The Venereal Disease Reference
Laboratory (VDRL) Test
- Mixture of Cardiolipin, cholestrol and licithin as Ag
- IgM or IgG Ab in positive serum or CSF
from neurosyphilis case causes a
suspension of lipoidal Ag to flocculate >
read by the eye
- Used as a screening test >
– 70% of primary and 99% of secondary syphilis
cases are positive
– Negative in late syphilis
- Quantitatively > diagnosis of congenital syphilis
- To monitor the efficacy of antibiotic therapy
2. Tests for Specific Antibody
i. Fluorescent treponemal Ab (FTA-Abs) test
– Indirect immunofluorescence assay
– T. pallidum = Ag
– Acetone-fixed treponemes incubated with heattreated sera > bound Ab detected by
fluorescin-labelled conjugate and UV
microscopy
– Positive in 80% primary, 100% secondary and
95% late syphilis patients.
– Remain positive after treatment
ii. T. pallidum haemagglutination assay (TPHA)
- RBCs coated with T. pallidum Ag
- Specific Ab in test sera >> haemaggluination
- Positive in 65% primary, 100% secondary and
95% late syphilis patients.
-Remains positive for life
iii. Other Antibody tests
- Monoclonal ant-T. pallidum Abs > ELISA
- Detects Ab response individual treponemal Ags
- Rapid screening of large number of samples
TREATMENT
 Primary
and Secondary Syphilis
– Prolonged high dose of procaine
penicillin
– Erythromycin, tetracycline or
choramphenicol
 Late
Syphilis
– Aqueous benzylpenicillin
CONTROL
 Treating
index cases and any
known contacts
Borrelia
 Gram-negative
 Cause
Relapsing fevers
 Transmitted by arthropod vectors
 Characterized clinically by
recurrent periods of fever and
spirochaetaemia
 Disease occur world-wide
Borrelia recurrentis
 Cause
epidemic or louse-borne
Relapsing fever
– An obligate human pathogen
– Person-to-person transmission by
the body louse Pediculus humanus
Other Borrelia
B. duttoni
 B. hermsii
 B. parkeri
 B. turicatae
 Cause endemic or thick-borne
relapsing fever
 Transmitted to humans by soft-bodied
Ornithodorus ticks
 Natural hosts

– Rodents and other small mammals
LABORATORY DIAGNOSIS
 Specimen
– Peripheral blood
 Thick
or thin blood smears
stained with Giemsa, acridine
orange or other stains
 Serological tests
– Not reliable (due to antigenic
variation) and not widely available
TREATMENT AND CONTROL
 Tetracycline,
Erythromycin,
chloramphenicol and penicillin
 Prevention
– Avoidance or eradication of the
insect vector
– Eradication of ticks from human
dwellings using insecticides
– Louse-borne infection
 Good
personnel hygiene
 If necessary >> delousing