Blinding trachoma: a disease of poverty.

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Trachoma is almost exclusively a disease of poor families and communities living in developing countries. It accounts for 15% of blindness worldwide—around
6 million people [1]. Although the disease is avoidable, it
continues to blind. With so few voices speaking out on behalf
of people affected by trachoma, it remains a neglected public
health issue.
Epidemiology
Trachoma, a chronic keratoconjunctivitis, is caused by
episodes of infection with Chlamydia trachomatis, an obligate
intracellular bacterium. Only serovars A, B, Ba, and C are
implicated in trachoma.
Trachoma is the second leading cause of blindness
worldwide [1]. According to the World Health Organization,
currently 84 million people, mostly children, have active
disease, and another 7.6 million people have trichiasis—a
stage of trachoma in which the upper eyelid turns inward
and one or more eyelashes rub against the eyeball [2]. An
estimated 10% of the world’s population lives in endemic
areas and is at risk of developing trachoma. Global loss of
productivity related to impaired vision and blindness from
trachoma is thought to be as high as $US 5.3 billion annually
[3]. More than 55 countries have been identifi ed as endemic
for trachoma, most of them in Africa and Asia (Figure 1) [4].
Humankind has known trachoma since antiquity. Ibn-e-
Isa, an Arab physician, was the fi rst person to describe the
different stages of trachoma and noted trichiasis as one of its
sequelae. So prevalent was the disease not so long ago that
trachoma hospitals were established in many parts of Europe
and America [5]. The disease then declined dramatically in
what is now called the developed world, mainly because of
socioeconomic development [4].
Transmission occurs from eye to eye via hands, clothing,
and other fomites. Flies have been identifi ed as a major vector
for the infection’s spread [6]. The presence of open latrines
favors the vector population (Figure 2). Factors associated
with trachoma include the extent to which the water supply
is limited, the distance from the water source, the amount
of water used for washing purposes, and overcrowding [7].
One case-control study in a Gambian village compared water
use in 18 families having one or more active trachoma cases
among the children with that in 16 trachoma-free families
in the same village. The families with trachoma were found
to use signifi cantly less water per person per day for washing
children than did the control group [8].
The Neglected Diseases section focuses attention either on a specifi c disease or
describes a novel strategy for approaching neglected health issues in general.
November 2004 | Volume 1 | Issue 2 | e44
Neglected Diseases
Blinding Trachoma: A Disease of Poverty
Pashtoon M. Kasi, Ahmed I. Gilani, Khabir Ahmad, Naveed Z. Janjua*
Open access, freely available online
DOI: 10.1371/journal.pmed.0010044.g001
Figure 1. The Worldwide Distribution of Trachoma
(Map: Silvio Mariotti/WHO)
Citation: Kasi PM, Gilani AI, Ahmad K, Janjua NZ (2004) Blinding trachoma: A disease
of poverty. PLoS Med 1(2): e44.
Copyright: © 2004 Kasi et al. This is an open-access article distributed under the
terms of the Creative Commons Attribution License, which permits unrestricted
use, distribution, and reproduction in any medium, provided the original work is
properly cited.
Abbreviation: WHO, World Health Organization
All authors are at the Aga Khan University, Karachi, Pakistan. Pashtoon M. Kasi
and Ahmed I. Gilani are students in the Medical College. Khabir Ahmad is a senior
instructor in the Ophthalmology Section of the Department of Surgery and a
research fellow in the Department of Community Health Sciences. Naveed Z. Janjua
is a senior research fellow in the Department of Community Health Sciences.
*To whom correspondence should be addressed. E-mail: naveed.janjua@aku.edu
Competing Interests: The authors declare that they have no competing interests.
DOI: 10.1371/journal.pmed.0010044

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The disease tends to cluster in certain communities within
a village and certain families within a neighborhood. Women,
especially in rural areas, are affected twice as often as men
[9].
Clinical Manifestations and Grading
Trachoma initially presents in childhood as red eye—itching,
redness, and pain. The essential lesion is a trachomatous
follicle (lymphoid cell aggregate) occurring typically in
the upper tarsal conjunctiva (Figure 3). The roughened
appearance of the upper tarsal conjunctiva gives the
disease its name (trachoma is the Greek word for “rough”).
Trachomatous involvement of the cornea manifests itself
initially as superfi cial keratitis. At a later stage, pannus
formation (new vessel growth) may occur over the margin of
the cornea, usually limited to the upper half.
In a subgroup of individuals, fi brosis occurs because of
repeated infections, resulting in scarring of the conjunctiva
(scarring trachoma). In scarring trachoma, the upper eyelid
is shortened and distorted (entropion) and the lashes
abrade the eye (trichiasis). Blindness results from corneal
opacifi cation, which is related to the degree of entropion or
trichiasis [10].
Based on the presence or absence of some of the key signs
of the disease, WHO has developed a simplifi ed grading
system for the assessment of trachoma (Figure 3) [11,12].
The system can easily be used by non-specialists, after
appropriate training, for the assessment of disease at the
community level.
Herbert’s pits (healed follicles in the superior limbus) and
Arlt’s line (a horizontal scar on the upper tarsal conjunctiva)
are two other classical features of the disease.
Managing Trachoma: The SAFE Strategy
WHO currently recommends the “SAFE” strategy for
the management of trachoma: Surgery for trichiasis,
Antibiotics for active disease, Facial hygiene, Environmental
improvement to reduce the transmission of the disease
[13,14,15].
Surgery. People with trachomatous trichiasis are at risk of
blindness, and so treating these people is the fi rst priority
for the SAFE strategy. An evidence-based review of the SAFE
strategy found that trichiasis surgery can alleviate discomfort
and improve vision, though the evidence is less clear on
whether such surgery prevents corneal opacifi cation [14].
The review authors suggested that a protective effect of
surgery against opacifi cation is likely.
There are different types of surgical procedures to correct
trachomatous trichiasis [16]. Their high costs and the lack of
surgical expertise in endemic regions, however, restrict the
use of many of these as public health interventions. On the
basis of a controlled trial by Reacher and colleagues [16],
WHO recommends the bilamellar tarsal rotation procedure
as the preferred technique; it is easy to perform and easy
to learn [17]. Surgical effectiveness is defi ned in terms of
recurrence of trichiasis; in the controlled trial, bilamellar
tarsal rotation produced a recurrence rate of around 20% at
follow-up 9–21 months after surgery, while other procedures
saw 60% of patients with recurrence of trichiasis in the same
period [16]. In several countries, different levels of health
staff, including nurses and ophthalmic assistants, have been
trained to perform the bilamellar tarsal rotation procedure.
In addition to recurrence, there are other problems with
the surgical approach to managing trachoma. It cannot
correct all the complications, such as dry eyes. Even more
important, and the main obstacle to preventing blindness
from trachoma, is the low rate of uptake of surgery by
communities with trachomatous trichiasis [14]. Barriers to
uptake include distance to travel to surgery, perceived cost of
the operation, child care duties, and lack of awareness about
the treatment [14]. In Tanzania, less than a fi fth of women
with trichiasis opted for surgery, even when it was offered for
free [18].
Offering surgery at the community level, rather than in
distant medical facilities, is one strategy that could reduce
travel times and costs and increase uptake. A cluster
randomized controlled trial of village-based surgery versus
health-center-based surgery in Gambia found a signifi cantly
higher uptake rate with the village-based service [19].
Antibiotics. The use of antibiotics aims to treat active
infection and eliminate the reservoir. WHO currently
recommends two regimens for the treatment of trachoma
in endemic regions. These are 1% topical tetracycline
ointment (twice daily for six weeks) or a single dose of oral
azithromycin (1 g in adults and 20 mg/kg in children) [20].
Although antibiotics are a cornerstone of the SAFE
strategy, clinical trials of antibiotics versus control (no
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DOI: 10.1371/journal.pmed.0010044.g002
Figure 2. A Typical Community in Which Trachoma Is Endemic
Some of the factors linked with the continued presence of the
disease in affected communities are lack of access to water,
overcrowding, lack of facial hygiene, eye-seeking bazaar fl ies, and
open latrines. (Illustration: Aslam Bashir, Aga Khan University)

PLoS Medicine | www.plosmedicine.org 107
treatment, placebo, or vitamin tablets) have produced
confl icting results and are diffi cult to pool because of
their heterogeneity. A recent Cochrane systematic review
concluded “there is some evidence that antibiotics reduce
active trachoma but results are not consistent and cannot be
pooled” [20]. The review also found that “oral treatment is
neither more nor less effective than topical treatment” [20].
Several questions remain about the use of antibiotics,
such as who should receive them and how often. Lietman
and colleagues have developed a mathematical model of
frequency of treatment that uses available epidemiological
data from a variety of countries [21]. Based on their model,
they recommend that in areas where trachoma is moderately
prevalent (less than 35% of children with active infection),
it should be treated annually, but in hyperendemic areas
(more than 50% of children with active infection), it should
be treated biannually. Such models, however, need to be
validated by well-designed clinical trials.
Facial hygiene. Good facial hygiene aims to reduce
transmission, the risk of autoinfection in a community, and
the risk of attracting fl ies [13,15]. Many cross-sectional surveys
have shown that children with clean faces are less likely to
have trachoma, and are less likely to have severe trachoma
[14]. A recent study in Mali found dirtiness of the face to be
the most important risk factor associated with trachoma [22].
A Cochrane systematic review found evidence that face
washing combined with topical tetracycline can be effective in
reducing severe active trachoma [23]. However, the evidence
does not support a benefi cial effect of face washing alone
or in combination with topical tetracycline in reducing non-
severe active trachoma [23].
Interventions aimed at promoting facial hygiene have not
yielded expected results in all settings, as behavioral change is
not always readily achievable.
Environmental improvement. This component of the
SAFE strategy also aims to reduce transmission of trachoma
by eliminating or reducing its risk factors, some of which are
ubiquitous while others are specifi c to a region. Improving
access to water is a key element. Other measures, such as
provision of latrines to reduce the fl y population, have also
been found effective in reducing transmission [6]. Such
environmental improvements will also provide other health
benefi ts to a community, such as reduction in the incidence
of diarrhea.
As mentioned previously, there is an important association
between water and trachoma—though the association is not
a simple one. The distance to the water source constrains
the amount of water used for hygiene practices. Improving
access to water on its own, however, may not be enough. In
the case-control study in Gambia, families with trachoma
used less water per person per day for washing children
than families without the disease, regardless of the amount
of water available [8]. In other words, interventions aimed
at increasing the availability of water should also promote
its appropriate use. Getting community “buy in” for these
interventions is important.
Why Is Trachoma So Neglected?
Trachoma is a disease of poor, underprivileged, and
socioeconomically disadvantaged communities. It affects
people who have little or no say in public decision
making [24]. Investing in trachoma may sometimes mean
compromising on other important issues. Many countries
in which trachoma is endemic are also marred by regional
confl icts, civil wars, and widespread corruption. Scarce
resources are being spent on arms and debt servicing. These
countries often lack the political commitment needed to fi ght
against the disease. In addition, there is a lack of commitment
by international donors.
Still, there is some room for optimism, given WHO’s
vision of the global elimination of trachoma by the year
2020 and the efforts of the International Trachoma
Initiative and other non-governmental organizations. The
implementation of the SAFE strategy to eliminate blinding
trachoma has already proven effective in several countries
[25]. Many countries have already started trying to eliminate
trachoma themselves.
Future Directions
Although the new initiatives in trachoma control are
encouraging, trachoma elimination programs clearly need
to be extended to many more countries. In addition, there
are three crucial steps that still need to be undertaken if
blindness from trachoma is to be eliminated.
First, there needs to be more emphasis on the “F” and “E”
components of the SAFE strategy. Antibiotics and surgery
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DOI: 10.1371/journal.pmed.0010044.g003
Figure 3. WHO Simplifi ed Grading System: A Guide for the Assessment of
Trachoma
(Photos: from [11], with permission from WHO)

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alone will not eliminate trachoma; work also needs to be done
to eliminate the risk factors and decrease the transmission
of the disease in affected communities. Such primary
prevention is more likely to have a sustainable impact but
requires a prolonged effort and investment [15,24]. Because
elimination of trachoma requires improvement in education
and hygiene practices, improved accessibility to water, and
economic development of endemic regions, collaboration
among departments and ministries is vital. An example of
such collaboration is the recent involvement of the Water
Supply and Sanitation Collaborative Council (www.wsscc.org)
in trachoma control efforts. Similar partnerships need to be
strengthened [25]. Socioeconomic development must be at the
heart of control efforts—trachoma was eradicated from much
of the developed world even before the advent of antibiotic
programs for trachoma, and much of this eradication was
attributable to socioeconomic development [26].
Second, research into different aspects of the disease
should continue. Work on a vaccine for trachoma, although
not successful thus far, should receive more attention [10].
Future research should look at risk factors for trachoma in
diverse communities and at barriers to implementation of the
SAFE strategy.
Third, awareness about the disease and the SAFE strategy
need to be promoted globally. At the same time, local, cost-
effective solutions to trachoma need to be encouraged.
Provision of pit latrines to reduce fl y populations is just one
such measure [6].
Unless these steps are taken, trachoma will continue to be
a major cause of blindness in communities in the developing
world [24]. �
Acknowledgments
We are deeply indebted to Aslam Bashir, medical illustrator at Aga
Khan University, for his work on the fi gures and tables, and to
Joseph Cook for helping us obtain some of the relevant literature.
Thanks are also due to WHO for graciously giving us the permission
to reproduce some of the fi gures. Sylvio Mariotti at WHO provided
us with the map of trachoma distribution and the latest fi gures on
disease epidemiology. Thanks to Riaz Baloch (Bolan Medical College,
Quetta, Pakistan) for sharing his clinical experience with trachoma
in Pakistan and to Masoom Kassi, Ali Zaidi, Fahd Anzar, and Talha
Khawar for their helpful suggestions.
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