2. INTRODUCTION
Trachoma is the leading infectious cause of ocular
morbidity
• It ranks in the top three causes of blindness worldwide.
Repeat infection with the organism Chlamydia
trachomatis leads to conjunctival inflammation and
scarring, trichiasis, and ultimately blinding corneal
opacification.
3. • Trachoma is an ancient disease, described clearly in the
Ebers papyrus of 1500 BC, and well known to the
ancient Greeks
• The name comes from the Greek word for rough ;a
reference to the characteristic appearance of the
subtarsal conjunctiva seen when the upper eyelid of an
individual with active disease is everted.
4. EPIDEMIOLOGY
Trachoma is leading cause of preventable irreversible
blindness in the world
The World Health Organization (WHO) reports trachoma
is endemic to more than 50 countries, with most
blinding trachoma in Africa.
It is responsible for the visual impairment of about 2.2
million people, of whom 1.2 million are irreversibly
blind*
*WHO Global Health Observatory (GHO) data
http://www.who.int/gho/neglected_diseases/trachoma
5. • During the last two centuries, trachoma retreated from
some formerly endemic regions, such as Europe and
North America
• Today trachoma is prevalent in large parts of Africa, and
in some regions of the Middle East, the Indian
Subcontinent, South-east Asia and South America.1
• The highest prevalence of trachoma is reported from
countries such as Ethiopia and Sudan where the
prevalence of active trachoma in children is often greater
than 50% and trichiasis is found in up to 5% of adults.2
1)Polack S, Brooker S, Kuper H et al. (2005) Mapping the global distribution of trachoma. Bull
World Health Organ, 83, 913–919.
2) Berhane Y, Worku A, Bejiga A (2006) National Survey on Blindness, Low Vision and
Trachoma in Ethiopia. Federal Ministry of Health of Ethiopia
9. AGE
• The prevalence of active disease peaks in pre-school
children and declines to low levels in adulthood
• In contrast to the signs of active disease, the prevalence
of trachomatous conjunctival scarring increases with
age,reflecting the cumulative nature of the damage
10.
11. GENDER
• Clinically active trachoma generally occurs with equal
prevalence in male and female children.
• However, in most areas women are more frequently
affected by the blinding complications than men
• About 75% of trichiasis and corneal blindness cases are
women, probably due to their greater lifetime exposure
to C.trachomatis infection through contact with children
12. • FAMILY based disease
• CLIMATE-More common in dry and dusty weather
• SOCIOECONOMIC STATUS- More commmon in poor
classes due to overcrowding,poor hygiene,flies,paucity
of water
13.
14.
15. PATHOGENESIS
• CAUSATIVE ORGANISM
• Chlamydiae are obligate intracellular gram-negative
eubacteria that exhibit a highly specialized biphasic
developmental cycle
16. • Genus is divided into four species:
Chlamydia trachomatis,
C. psittaci,
C. pneumoniae, and
C. pecorum.
• C. trachomatis and C. pneumoniae are important
human pathogens, whereas C. Psittaci and C. pecorum
are primarily pathogens of animals and birds, rarely
infecting humans
17. Chlamydia trachomatis
• 19 different serovars based on immunological cross-
reactivity of the major outer membrane protein (MOMP).
• These are sub-divided into two biovars; the trachoma
biovar (serovars A–K) and the lymphogranuloma
venereum biovar (serovars L1, L2, L2a and L3).
• Endemic trachoma is caused by serovars A, B, Ba and
C.
• Genital chlamydial infection, which causes pelvic
inflammatory disease and infertility, is associated with
serovars D–K.
18.
19. • The elementary body (EB) is a metabolically inert
form of the organism that is responsible for infecting the
host cell.
• Once host cells take up organisms, they are confined to
a vacuole known as the inclusion.
• Within the inclusion, the bacteria are protected from
lysosomal fusion and differentiate into the metabolically
active reticulate body (RB) form.
• Reticulate bodies replicate within the inclusion,
converting back into Elementary Bodies just before cell
lysis.
20.
21. • C. trachomatis infection mobilizes all arms of the
adaptive immune system.
• Antibodies elicited against outer membrane proteins of
C. trachomatis aid in blocking attachment and
subsequent internalization of the bacteria by host cells
• Once organisms have entered host cells and begun
developing, clearance of the bacteria requires the activity
of T cells. In a number of studies, CD4+ T cells have
been shown to play a crucial role in host defense against
C. trachomatis.
22. • Infection causes inflammation, that is, a predominantly
lymphocytic and monocytic infiltrate with plasma cells
and macrophages in follicles.
• The follicles are typical germinal centers with islands of
intense B-cell proliferation surrounded by seas of T cells.
• The clinical changes are a delayed-type hypersensitivity
reaction to the chlamydial antigens (thought to be HSP-
60).
23. • C trachomatis has evolved various ways to evade the
host immune response.
• First, its intracellular location protects it from attack by
antibody and complement.
• Second,expression of MHC class I molecules at the
surface of infected cells is downregulated, reducing the
likelihood that the cells will be recognised and killed by
class-I-restricted cytotoxic T cells.
• Last, fusion of the phagosome (containing the ingested
organism) with host-cell lysosomes (containing
microbicidal substances) is actively prevented.
28. • Clinically, trachoma is sub-divided into active (early) and
cicatricial (late-stage) disease -these phases are not
stages along a linear pathway of disease pathogenesis;
both phases may coexist in the same patient
SYMPTOMS
• Many infections are asymptomatic.
• In other cases, following an incubation period of 5 to
10 days, conjunctival infection produces an irritated, red
eye and scanty mucopurulent discharge.
• Involvement of the cornea in the acute inflammatory
process can cause pain and photophobia.
CLINICAL FEATURES
31. • First sign of infection is a nonspecific vasodilation of
conjunctival blood vessels
• Follicles develop subjacent to the conjunctivae of the
fornices, the tarsal plates, and the limbus
• Papillae may also be noted at this stage: in mild cases,
a few isolated, small red dots can be seen with the
naked eye. When inflammation is severe, an intense
papillary reaction on the tarsal conjunctiva is associated
with a diffuse thickening of the conjunctiva, obscuration
of the deep tarsal vessels, and, sometimes, eyelid
edema.
32. • If the cornea is involved in the inflammatory process, a
superficial punctate keratitis may be noted.
• Superficial infiltrates or pannus (subepithelial
• infiltration of fibrovascular tissue into the peripheral
cornea), also indicate corneal inflammation.
• Follicles, papillae, and these corneal signs are
features of active disease.
33.
34. • Resolution of follicles may be accompanied by scarring
of the subepithelial conjunctiva.
• Scar deposition is most prominent in the upper tarsal
plate - Arlt's line (a horizontal line that results from
conjunctival scarring at the junction of the anterior one
third and posterior two thirds of the conjunctiva) is a
characteristic finding on the superior pretarsal
conjunctiva.
• At the limbus, replacement of follicles by scar results in
the formation of translucent depressions in the
corneoscleral junction called Herbert’s pits.
35.
36. • If sufficient tarsoconjunctival scarring accumulates,
contraction of it over the years will cause the upper
eyelid to turn inward so that the lashes rub against the
globe. This is known as trichiasis.
• When the whole lid margin is turned in, the condition is
known as entropion.
• Secondary bacterial and fungal infections of the cornea
and corneal drying due to scarring of forniceal-
mucous, lacrimal, and meibomian glands accelerate
epithelial damage.
40. FPC CLASSIFICATION
Dawson CR, Jones BR, Tarizzo ML. Guide to trachoma control in
programmes for the prevention of blindness. Geneva: World Health
Organization, 1981
53. • Cicatricial conjunctivitis can be caused by mucus
membrane pemphigoid, Stevens–Johnson syndrome,
systemic sclerosis, chemical injuries and drugs.
• In nontrachomatous areas, most cases of entropion are
due to involutional changes. Two rare congenital
disorders result in lashes touching the eye: epiblepharon
(upward riding of skin and orbicularis over the inferior
tarsus) and distichiasis (additional row of lashes arising
from the meibomian gland orifices).
54. MANAGEMENT
• The World Health Organization in the year 1997 formed
an Alliance to work towards the Global Elimination of
Trachoma by the year 2020 (GET 2020).
• The Alliance promotes the use of SAFE strategy for
trachoma control.
• S = surgery
• A = antibiotics
• F = facial cleanliness
• E = environmental improvement
55. SURGERY
• Some advocate early surgery when one or more lashes
touch the eye, whereas others practice epilation until
more severe TT develops.
• As the progression of TT can be quite swift in some
people, where access to ophthalmic services is limited,
surgery for mild disease is a logical approach.
• A major problem limiting the effectiveness of surgery is
the recurrence of trichiasis following surgery, which
can be as high as 40–60%.
• Bilamellar tarsal rotation (BLTR) was found to have
the lowest TT recurrence rate and was therefore
endorsed by the WHO
59. • Currently two antibiotics are recommended for the
control of trachoma: 1% tetracycline eye ointment and
oral azithromycin.
• Tetracycline can clear the ocular infection if administered
twice daily for 42 days but is ineffective in clearing
extra ocular reservoirs. The compliance is poor for this
drug.
• Oral azithromycin is well tolerated and has the
advantage of good compliance. The dose is 20 mg/kg
for children and 1 gm for adults (>18 years). The drug
not only clears the ocular infection but also acts on the
extra ocular reservoirs
60. • Azithromycin is not used in infants under the age of 6
months.
• The WHO currently recommends that a 6 week course of
topical tetracycline be used for infants under 6 months.
• Currently 12 trachoma endemic countries are receiving
azithromycin as part of a philanthropic donation from the
manufacturer (Pfizer Inc.).
61. • There are no long-term data to guide programmes as to
how long mass antibiotic treatment should be given and
this remains a difficult area that requires further
research.
• The current recommendation from the WHO is that three
annual rounds of mass treatment should initially be
given.
• After this, the community should then be re-assessed to
see whether the prevalence of active disease has
dropped sufficiently to discontinue treatment.
62. FACIAL CLEANLINESS AND ENVIRONMENTAL
IMPROVEMENTS
• The F&E components of the SAFE strategy are primarily
targeting the transmission of C. trachomatis between
individuals
• By washing away potentially infected ocular secretions,
the transmission of C. Trachomatis to others might be
interrupted
• Controlling the fly population - (1) insecticide spray,
(2) latrine provision
• General improvements in water supply (for face
washing) and sanitation (to suppress fly populations).
63. • This drive has fortunately coincided with the setting of
the United Nations’ Millennium Development Goals
(MDG).
• The target for the seventh MDG is to halve the number
of people without safe water and basic sanitation by
2015
