The End of Blinding Trachoma Among the World's Poor Is in Sight

by Beryl Lieff Benderly

 

The Path to Blindness | Playing it SAFE 

Early in the last century, at the Ellis Island immigration station in New York, a young translator named Fiorello La Guardia watched as long lines of poor Europeans just off crowded ships waited in hope and trepidation for the medical exam that would determine their fitness to enter the United States. The immigration service doctors tapped chests, listened to hearts, and, often using buttonhooks, turned back eyelids to peer underneath for signs of trachoma, a contagious and potentially blinding eye disease. The diagnosis meant automatic exclusion from the country.

La Guardia became mayor of New York, and his memoirs recalled “harrowing” incidents of families separated by the diagnosis. “If it was a young child who suffered from trachoma,” he wrote—and, given the disease’s epidemiological profile, this was often the case—“one of the parents had to return to the native country with the rejected member of the family.”¹

Despite the misery that trachoma caused to so many, however, few who live today in the United States or Europe  know anything about an infection so feared by their immigrant ancestors. Before antibiotics and modern sanitation eradicated trachoma from those regions in the mid-20th century, however, it had been so common that the U.S. government excluded any alien with signs and symptoms and operated special hospitals for American victims.

More than 50 years have passed since trachoma has been eradicated from the United States, and more than 20 since the advent of the antibiotic azithromycin, which can stop the infection in as little as a single oral dose. The new drug greatly improved on the best treatment then available—several weeks or months of twice-daily doses of the antibiotic tetracycline applied in ointment form to often painful and inflamed tissues.²  Nonetheless, in many parts of the developing world, millions of the world’s poorest people still face the risk—and, often, the reality—of losing their sight and suffering extreme discomfort because of a scourge now gone wherever people have access to safe water and adequate health care. Trachoma has earned the designation of a neglected tropical disease (see box).

Trachoma thrives in conditions of deep poverty and actually helps perpetuate poverty by robbing people of the ability to work, learn, and contribute to their communities, making them dependent rather than productive. Their losses begin long before their sight is gone, because pain and other problems are so debilitating.³

In La Guardia’s time, the suffering that trachoma caused was unavoidable. In our time, multiple, effective, and cost-effective methods can halt the infection and damage that lead to pain and, ultimately, blindness.⁴  Along with antibiotics to cure the infection, proper hygiene and sanitation can prevent its spread from person to person. And simple surgery can reverse the disease’s most harmful and painful effect before it destroys eyesight.

Shockingly, though, trachoma remains one of the world’s most common causes of preventable blindness and the largest cause of blindness due to infection. It affects people throughout much of Africa and Western, Southeast, and East Asia, as well as Brazil and parts of Australia (the only developed country with regions where trachoma remains endemic).⁵  In recent years, the toll has been declining in a number of countries thanks to improvements in living conditions and modern medical care.⁶  Nonetheless, the scale of suffering from trachoma remains immense. According to the most recent available worldwide estimates, some 7.6 million persons are living with trachoma-related blindness or severe visual impairment, 40.6 million have active trachoma, and 8.2 million have trichiasis (ingrown eyelashes caused by trachoma that can lead to blindness).⁷ 

The World Health Organization is leading a worldwide campaign called the Alliance for the Global Elimination of Trachoma by the Year 2020 (GET 2020). Because trachoma-caused blindness results from a multistep process, reducing the risk among vulnerable populations requires a number of coordinated steps, an approach that has already greatly reduced trachoma in Morocco.⁸  But success will be achieved worldwide only if rich nations and international organizations continue to provide, despite the current global economic crisis, the resources needed to realize the vision of a world without trachoma.

The Path to Blindness

That people still fall prey to blindness so easily prevented is a grave inequity. Even worse, vision loss happens neither quickly nor in the infection’s early stages, but only after years, even decades, of painful deterioration that could have been treated and stopped at any point. The word “trachoma” comes from the Greek for “rough eye” and refers to the abrasion of the eyeball that ultimately destroys victims’ sight.

Trachoma is an infection by the bacterium Chlamydia trachomatis of the tissues around the eye, the conjunctiva. It may be symptomless, especially at first, but is often accompanied by inflammation that includes a fluid discharge and irritation of the issues that surround the eyeball and line the eyelid. Depending on the infection’s severity, the inside of the eyelid may become red, swollen, pitted, and thickened. Scarring can occur on its underside and in the tear ducts near the eye, which in turn can affect the supply of tears needed to keep the eye surface moist.⁹

Over time, lengthy or repeated infections may cause scarring sufficient to distort permanently the shape of the upper lid, causing it to contract and its edge to turn under, so that the lashes rub against the eyeball, a condition known as trichiasis. Victims suffer constant discomfort of a foreign body in the eye and, even more significant, the lashes rub against the cornea, (the clear portion of the eyeball that admits light), causing abrasion and, eventually, scarring of that delicate and crucial tissue. The damage also increases susceptibility to infections by other bacteria or fungi, a risk further heightened by the presence of the wet lashes and the absence of the normal quantity of cleansing tears.¹⁰ 

As the damage advances with time, the cornea grows more and more opaque and the person’s vision declines, eventually resulting in blindness. Where trachoma is endemic, trichiasis in both eyes afflicts as many as one in 10 of the over-40 population and accounts for as much as 40 percent of vision loss.¹¹

The age group likeliest to harbor active, inflammatory trachoma infection is children under 5, with highest incidence in those between ages 1 and 3. As with many infections, young children’s developing immune systems gradually lessen both their susceptibility to the bacterium and their rate of active disease. The burden of trachoma-caused blindness, however, falls on adults, and most heavily on women, who are nearly four times likelier than men to develop trichiasis and to lose their vision.¹²  Between 60 percent and 85 percent of trichiasis sufferers are women.¹³

Women’s role as primary caretakers of small children, and girls’ role as their mothers’ helpers, results in their greatly disproportionate risk. Whether any biological factors may increase women’s and girls’ vulnerability to C. trachomatis or to corneal damage is not known. Some researchers suspect dry eye syndrome as a factor that raises the risk of corneal damage; studies in developed countries have found it to be more common in women than men, possibly for hormonal reasons. Probably much more relevant to the gender difference in trachoma, experts agree, is the close connection, which has been found, for example, in studies of Tanzanian women, between being the mother or caretaker of young children and having active trachoma infection.¹⁴   

 
Playing it SAFE

The effective treatments now available for C. trachomatis cannot alone protect residents of endemic areas from the ravages of trachoma. “Trachoma is a community disease, which clusters in neighbourhoods and within families,” writes Sheila K West of the Wilmer Eye Institute at Johns Hopkins University.¹⁵  The bacterium spreads easily through contact with the secretions of infected eyes, directly or on contaminated hands, towels, clothing, and other objects. Many endemic areas also harbor flies, especially of the species Musca sorbens, that almost seem designed as vehicles to spread trachoma. The flies feed on human eye and nose secretions and often cluster on or around the faces of individuals with exuding infections, picking up the bacterium and delivering it to the eyes of the next person they visit. In addition, the flies’ breeding ground is uncovered human feces; they appear unable to reproduce in properly built latrines. 

The conditions in which many of the world’s poorest people have to live provide ideal conditions for trachoma infections to be common and recurrent.  Families who have many small children and live in crowded quarters tend to share their household articles. Lack of ready access to safe water ensures that hands, faces, clothing, bedding, and other objects likely to harbor the bacterium are rarely washed. Scarce health care allows infections to go untreated. Absence of sanitary facilities requires people to relieve themselves in the open, providing a breeding ground for eye-seeking flies. Dirty hands, towels, and clothes also introduce additional infectious agents into eyes already made susceptible to infection by the abrasion of trichiasis.

With so many interrelated factors promoting the disease, experience shows that eliminating blinding trachoma requires a concerted assault on many fronts. And that, in turn, requires sustained campaigns covering whole communities rather than individual patients or families. “Treatment of a few cases in such a setting guarantees re-infection from familial or neighbourhood sources, unless the treatment is more widespread,”¹⁶  writes West. To meet the challenge of trachoma, WHO therefore supports a four-pronged strategy known as SAFE: Surgery, Antibiotic, Facial cleanliness, Environmental improvements.

Each of the acronym’s letters stands for an element necessary to a successful eradication campaign. First is surgery, the simple, inexpensive operations that can end trichiasis. WHO recommends a procedure called bimellar tarsal rotation, which slits the damaged eyelid horizontally and sutures it back together so that the lashes no longer point inward toward the eyeball. In the hands of a skilled practitioner, the procedure takes less than half an hour under local anesthetic. Trichiasis can return after surgery, especially if the patient becomes reinfected, but this procedure has shown a particularly low rate of recurrence.¹⁷  Experience in a number of countries lacking adequate numbers of physicians show that the operation is well within the capabilities of non-physicians such as nurses, who receive special training. But even so, in many countries, less than half of those who could benefit from surgery actually undergo it. Distance, fear, cost, and lack of someone to take over household duties are some of the obstacles cited by people—overwhelmingly women—who decline the operation.¹⁸ 

The three other letters relate to methods of preventing spread of infection. The "a" stands for antibiotic, generally oral azithromycin. Pfizer, the company that manufactures azithromycin under the trademark Zithromax, has committed to provide pills for trachoma eradication in poor countries free of charge. Pfizer's donation already tops a million doses, and it promises to donate many times more.¹⁹  Administering one dose a year to everyone in a village over the age of 6 months and not pregnant has proven in trials to effectively rid communities of active infection. Treating the entire population is important because infected people may lack symptoms. Infants and pregnant women receive treatment with tetracycline ointment. Even when the drug is free, however, administering to poor communities involve costs that may exceed the available resources in some countries.²⁰
 
Facial cleanliness appears to help break the chain of infection. Robin Bailey of the London School of Hygiene and Tropical Medicine and Tom Leitman of the University of California-San Francisco cite “considerable evidence that persons with clean faces are less likely than others to have active trachoma. Consequently, there is an assumption that promoting hygiene may reduce trachoma"--an assumption apparently borne out by research.²¹  
 
Encouraging clean faces in endemic areas involves both educating families about the importance of washing and providing access to the safe water that makes it possible. J-F Schemann of the Institute of African Tropical Ophthalmology in Bamako, Mali,  and co-authors, note  that “several studies have found an association between distance to the water sources and prevalence of trachoma among children,”²²  Where getting clean water is impossible or requires a lengthy trek, families are likely to use it sparingly for washing faces, hands, clothes, linens, and bodies. This infection factor calls for environmental improvement--generally in the form of convenient water sources and pit latrines that substantially reduce the fly population. 

A three-year study in four districts in Sudan found that the antibiotic, facial cleanliness, and environmental improvement interventions “independently associated with reduced prevalence of active trachoma". These findings “reinforce the argument for implementing the full SAFE strategy as an integrated approach to control of blinding trachoma,” especially because it is “adaptable to many different situations.”²³

SAFE also requires detailed planning, ongoing coordination, sustained effort, and considerable resources. The world’s poor will only “GET 2020” and get rid of trachoma with the continuing commitment of donors, international organizations, and host-country governments. The current economic crisis could endanger needed international commitment and thus perpetuate the neglect. The technical basis of the SAFE strategy is sound, experts agree, and the end of trachoma is attainable. “Although significant hurdles remain," with adequate support, write Bailey and Leitman, “there is every reason to hope that GET 2020 will be successful^.”24 

Beryl Lieff Benderly is a prize-winning Washington journalist and author specializing in health, behavior, and science policy. Her articles appear in major magazines and on the Internet, and she is a regular contributor to the Science magazine website. Her eight books include In Her Own Right: The IOM Guide to Women’s Health Issues.
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¹Cook, J.A. 2008. “Eliminating Blinding Trachoma.”  New England Journal of Medicine 358: 1777-79. http://content.nejm.org/cgi/content/full/358/17/1777

²Cook, J.A. 2008.

³Courtright, P., and S. K. West. 2004. “Contribution of Sex-Linked Biology and Gender Roles To Disparities With Trachoma.” Emerging Infectious Diseases. www.cdc.gov/ncidod/EID/vol10no11/04-0353.htm

⁴Ngondi, J., and others. 2008. “Associations between Active Trachoma and Community Intervention with Antibiotics, Facial Cleanliness, and Environmental Improvement (A, F, E).” PLoS Neglected Tropical Diseases 2(4): e299.

⁵Mak, D.B. 2006. “Better Late Than Never: A National Approach to Trachoma Control.” Medical Journal of Australia 184(10): 487-88. www.mja.com.au/public/issues/184_10_150506/mak10306_fm.html

⁶Mariotti, S. P., D. Pascolini, and J. Rose-Nussbaumer. 2008. “Trachoma: Global Magnitude of a Preventable Cause of Blindness.” British Journal of Ophthalmology http://bjo.bmj.com:80/cgi/rapidpdf/bjo.2008.148494v1.pdf

⁷Mariotti, S.P., D. Pascolini, and J. Rose-Nussbaumer. 2008.

⁸What Works Working Group. 2004. “CASE 10: Controlling Trachoma in Morocco.” Millions Saved: Proven Success in Global Health. Center for Global Development. www.cgdev.org/section/initiatives/_active/millionssaved/studies/case_10

⁹Kuper, H., and others. 2003. “A Critical Review of the SAFE Strategy for the Prevention of Blinding Trachoma.” Lancet Infectious Disease 3: 372-81.

¹⁰Kuper, H., and others. 2003.

¹¹Kuper, H., and others. 2003.

¹²(a) Frick, K.D., C. L. Hanson, and G. A. Jacobson. 2003. “Global Burden of Trachoma and Economics of the Disease.” American Journal of Tropical Medicine and Hygiene 69 (5): 1-10. (b) Courtright, P., and S. K. West. 2004.

¹³Courtright, P., and S. K. West. 2004.

¹⁴Courtright, P., and S. K. West. 2004.

¹⁵West, S. K. 1999. “Azithromycin for Control of Trachoma.” Community Eye Health 12 (32): 55-56. www.pubmedcentral.nih.gov/articlerender.fcgi?artid=1706032#B1

¹⁶West, S. K. 1999.

¹⁷Kuper, H., and others. 2003.

¹⁸Kuper, H., and others. 2003.

¹⁹Bailey, R., and T. Leitman. 2001. “The SAFE Strategy for the Elimination of Trachoma By 2020: Will it Work?” Bulletin of the World Health Organization 79: 233-36.

²⁰Kuper, H., and others. 2003.

²¹Bailey, R., and T. Leitman. 2001.

²²Schemann, J. F., and others.  2003. “Risk Factors for Trachoma in Mali.” International Journal of Epidemiology 31: 194-201.

²³Ngondi, J., and others. 2008.

²⁴Bailey, R., and T. Leitman. 2001.