2. INTRODUCTION The bacteria in the taxonomic family
Chlamydiaceae
Small (0.3–1 lm) obligate cell parasites
Gram-negative cell wall
Bacteria but similar to viruses
3. OBLIGATE PARASITES
Obligate intracellular parasites of mammals and birds
not transmitted by arthropods.
incorrectly called the PLT viruses or Bedsonia or basophilic viruses,
Multiply in the cytoplasm of the host cell.
4. SIMILAR TO VIRAL
INFECTIONS
The methods used to study Chlamydia
are those of the virologist rather than the
bacteriologist.
The clinical features, pathogenesis,
pathology and epidemiology of
chlamydial infections are similar to those
of viral infections.
5. ENERGY PARASITES The cells can synthesize DNA, RNA and
protein.
No flavoproteins or cytochromes.
lack of ATP-generating ability
need to obtain ATP from the host cell.
6. MORPHOLOGY AND DEVELOPMENTAL CYCLE.
Two morphologically and functionally
distinct forms are known:
Elementary body
Reticulate Body
7. CHLAMYDIAL MORPHOLOGIES
Elementary body
metabolically inactive infectious forms
0.25 - 0.3 um diameter
electron-dense nucleoid
Released from ruptured infected cells. Human to human & bird to human.
EBs are resistant to many harsh environmental factors
8. CHLAMYDIAL MORPHOLOGIES
Reticulate Body
metabolically active, noninfectious forms
Intracytoplasmic form 0.5 - 1.0 um
Replication and growth. ( Inclusion body )
without a dense center.
9. 1.Elementary
body (EB)
attaches to
surface of cell.
2. Elementary
body enters by
endocytosis.
3. Elementary
body enters
endosome.
4. Elementary
bodies
reorganize into
reticulate bodies
(RB).
10. 5. Reticulate
bodies (RB)
replicate.
6. Reticulate
bodies (RB)
reorganize into
Elementary
bodies (EB)
7. Both RB and
EB reside in
inclusion
granule.
8. Reverse
endocytosis
13. TRACHOMA
Follicular keratoconjunctivitis
One of the leading cause of preventable blindness
Chronic, inflammatory granulomatous process of eye surface,
leading to corneal ulceration, scarring, pannus formation, and
blindness
14. PREDISPOSING
FACTORS:
climate - hot , dry
shortage of water
standards of hygiene low
Transmitted by flies, dirty towels, fingers, cosmetic eye pencils.
Initial infection in childhood mostly by 10-15 years of age.
15. FLIES ALSO PLAY A MAJOR ROLE IN THE
SPREAD OF THE DISEASE.
http://bjo.bmj.com/content/88/6/750.full
18. CLINICAL FEATURES
Early Acive stage
usually seen in childhood,
Characterised by recurrent episodes of chronic, follicular
conjunctivitis.
Follicles are subepithelial collections of lymphoid cells and appear
as small, yellow-white elevations on the conjunctiva of the everted
upper lid.
Papillary hypertrophy (engorgement of small vessels with
surrounding oedema) also occurs and can obscure the deep tarsal
vessels if severe enough.
19. CLINICAL FEATURES
Early Acive stage
Vascular infiltration of the upper cornea (pannus) may also develop in active disease, but this rarely
affects vision.
Conjunctival follicles at the upper margin of the cornea leave shallow depressions after they resolve
known as ‘Herbert’s pits
Herberts
pit
20. CLINICAL FEATURES
Late Cicatrical stage
conjunctival scarring
Contraction of this scar tissue causes
entropion
Trichiasis
Corneal opacity
21. WHO CLASSIFICATION
FISTO
1. TF: Trachomatous inflammation-follicular.
The presence of five or more follicles (each >0.5 mm in diameter) in the upper tarsal
conjunctiva
2. TI : Trachomatous inflammation intense.
This stage is diagnosed when pronounced inflammatory thickening of the upper tarsal
conjunctiva obscures more than half of the normal deep tarsal vessels
3. TS:Trachomatous scarring
The presence of scarring in the tarsal conjunctiva
4. TT: Trachomatous trichiasis
At least one lash rubs on the eyeball
5. CO: Corneal opacity
Easily visible corneal opacity over the pupil
28. OTHER DISEASES BY CHLAMYDIA TRACHOMITIS
Inclusion conjunctivitis.
• This is an acute,
purulent papillary
conjunctivitisthat may
affect neonates,
children, and adults
Genital infections
Lymphogranuloma
venereum.
• This venereal disease
(syn. Lymphogranuloma
inguinale, lymphopathia
venerea
Editor's Notes
WHO Prevention and Blindness and Visual Impairment
http://trachoma.org/safe-strategy
BBC Documentary
A huge factor in the elimination of trachoma is a change in some cultural habits. Clean water is also essential