Trachoma is a chronic eye infection caused by Chlamydia trachomatis, a bacterium at first thought to be a virus because of its minuscule size. It is the most common infectious cause of blindness worldwide, striking repeatedly in early childhood and, until recently, blinding millions.¹ In 1907, Ludwig Halberstadter and Stanislaus von Prowazek observed the causative agents as inclusion bodies inside infected cells and believed them to be protozoa. The infectious nature of the disease was widely known by World War I, when hundreds in Europe evaded military service by infecting their eyes with discharges wiped from the eyes of trachoma patients.

It was not until 1957 that Dr. Feifan Tang completed the first successful isolation of the bacterium in Peking using chicken embryos whose yolk sacs had been inoculated with material from infected human eyes. It is said that he infected himself with chicken eggs to collect experimental data. The word trachoma comes from the Greek trachys, meaning “roughness.”

The disease is a very ancient one. Archeologists found skeletons suggesting it may been present since the Ice Age (8000 BC) in many areas, including Australia, where it continues to infect indigenous people. Described in China by 2500 BC and also in the Ebers Papyrus and by Hippocrates, it was common among Roman soldiers. Arab authors wrote about it, and the Crusaders spread it to Western Europe. Saint Francis of Assisi may have contracted the disease while visiting the Middle East around 1220 and was blinded by it and not by shedding tears for the sins of the world. When Napoleon landed in Egypt with an army of 35,000 men in 1798, the disease spread with such rapidity that several hospitals had to be erected for the men, of whom some one thousand lost their sight.² The poet William Wordsworth had recurring bouts of trachoma during the latter part of his life, and he wrote in his poem “The Excursion” about his fear of losing his sight.

The Chlamydia organism is found in personal secretions and is spread by hand-eye contact, nasal secretions, contaminated objects, or flies. Following repeated infections of the conjunctivae (follicular conjunctivitis), the disease causes sensitivity to light, excessive tearing, and redness of the upper eyelid. It progresses to scaring of the conjunctiva and of the cornea, causing opacities and eventual blindness.

Trachoma is foremost a disease of poverty. It thrives among remote, marginalized, and displaced populations, afflicting some of the poorest regions of the globe. In the nineteenth century, it reached epidemic proportions in Europe and America, and during the Industrial Revolution, urbanization, overcrowding, and unsanitary living conditions favored its spread. It was so prevalent that as the disease was untreatable; immigrants to the United States were checked for trachoma on Ellis Island and sent back to their country of origin if tested positive for the disease. At one time, the disease was treated in special trachoma hospitals, of which Moorfields Eye Hospital in London is one of the most famous.

The development of antibiotics, first tetracycline, and in 1993 azithromycin (effective as a single dose) revolutionized treatment, as did surgery, aided by better hygiene and overall improved living conditions. The disease remains a public health problem in many countries. Efforts to eliminate it are based on strategies such as SAFE (Surgery, Azithromycin antibiotics, Facial cleanliness, and Environmental improvement); and thanks to the efforts of the World Health Organization, local governments, and private foundations. In the past decade, the disease has been eliminated from Morocco, Mexico, Cambodia, Laos, Ghana, Nepal, Iran, Gambia, Malawi, Benin, and Mali. However, it remains a significant cause of blindness in many countries, calling for continuing efforts to eradicate it, and it has been suggested that the end is in sight for eliminating the disease perhaps as early as 2025.

References

1. Trachoma. Wikipedia. https://en.wikipedia.org/wiki/Trachoma
2. HF Lechmere Taylor. Trachoma. The Public Health Journal 4, no. 7 (July 1913): 406-10.