Trachoma
Trachoma
Disease History, Characteristics, and Transmission
Introduction
Trachoma, also called granular conjunctivitis and Egyptian ophthalmia, is a contagious bacterial disease of the eye caused by the bacterium Chlamydia trachomatis. Flies become infected when they lay eggs on human feces lying in soil. The infection occurs when a host fly, infected with the bacterium, bites a human. A fly can also become a host and harbor the bacteria when it makes direct contact with eye, nose, or throat secretions from an infected person. The bacterium can also be carried directly to humans from contaminated hands byfomites (objects contaminated with infective material) such as clothing. The disease is reported as one of the leading infectious causes of blindness.
Disease History, Characteristics, and Transmission
The International Trachoma Initiate (ITI) states that trachoma is one of the oldest infectious diseases known to humankind, and was reported as far back as ancient Egypt. General improvements in public health and sanitation have eliminated trachoma from most industrialized nations such as those in North America and Europe. However, it continues to infect people at high rates in underdeveloped and developing countries, especially in the poorest areas of Africa, Asia, Australia, Latin America, and the Middle East.
An incubation period of about five to 12 days occurs before the eye becomes inflamed. Then, additional symptoms occur, including pus discharge, eyelid swelling, eye tearing, and light sensitivity. Within a few weeks, more symptoms begin to appear including chronic swelling (such as swelling of lymph nodes in front of the ears), eye blisters, cornea clouding, and cornea scarring. Extensive damage to the cornea can eventually lead to blindness.
Scope and Distribution
The ITI estimates that about eight million people are visually impaired due to trachoma and about 84 million people in 55 endemic countries suffer active symptoms. The World Health Organization (WHO) states that about 3.6 million people are blind from trachoma.
Trachoma occurs most commonly among populations living in overcrowded conditions and with limited contact to clean water and health care facilities such as in undeveloped villages in northern Africa. Children and women who take care of children are most susceptible to trachoma. Children between the ages of three and five years, according to the WHO, are most at risk of all groups of children. When infected early in life, the person may not notice the degradation in sight until adulthood.
Because close personal contact allows easier transmission of the disease, the ITI states that in many crowded African communities it is so prevalent that trachoma is considered a regular part of life. In the United States and other technologically advanced countries, trachoma is rare, but can occur in populations living in extreme poverty and crowdedness, and with poor hygienic conditions.
Treatment and Prevention
According to the National Library of Medicine (NLM), of the National Institutes of Health (NIH), symptoms start as an apparent irritation near the eye, what is sometimes called conjunctivitis (commonly called pink eye). Soon, hard pimples or granular outgrowths appear on the inner surface of the eyelids and inflammation occurs on its membrane.
If left untreated, scar tissue develops on the inside of the eyelid. Such scarring in children is usually not noticeable until later in the adult years. Formation of scarring eventually forces the eyelid to curve inward and the eyelashes to scrape the eye. Severe infection of the cornea can later occur. This activity can cause eye ulcers, which further cause scarring and vision problems. Eventually, slow and painful blindness develops over many years.
In the early stage of the infection, trachoma responds well to oral or topical antibiotics such as azithromycin, doxycycline, and erythromycin. Officials from NLM/NIH report that people who receive early treatment for trachoma before scarring and lid deformities occur have excellent chances to be cured. WHO recommends using oral eye ointments such as azithromycin and tetracycline to control trachoma.
WORDS TO KNOW
FOMITE: A fomite is an object or a surface to which an infectious microorganism such as bacteria or viruses can adhere and be transmitted. Transmission is often by touch.
HOST: Organism that serves as the habitat for a parasite, or possibly for a symbiont. A host may provide nutrition to the parasite or symbiont, or simply a place in which to live.
MORBIDITY: The term “morbidity” comes from the Latin word “morbus,” which means sick. In medicine it refers not just to the state of being ill, but also to the severity of the illness. A serious disease is said to have a high morbidity.
According to WHO, relief from trachoma can be attained by following the SAFE strategy: surgery, anti-biotics, facial cleanliness, and environmental improvement. Thus, surgery can be performed to correct advanced problems related to the disease. Early treatment with antibiotics can prevent long-term complications. Good hygiene should be consistently and thoroughly practiced such as washing of the face in order to reduce transmission. Access to clean water and improved sanitation facilities (especially the safe disposal of human and animal feces) also greatly help to reduce the occurrence and severity of the disease.
In addition, regular eye examinations can pinpoint abnormal redness on the white areas of the eyes, scarring on the inside of the upper eyelid, and improper blood vessel growth on the corneas. Laboratory tests, especially the polymerase chain reaction (PCR) technique, are used to identify the bacterium that causes trachoma. Such tests, however, are usually too costly for use in the poorest areas of the world where trachoma occurs the most.
Impacts and Issues
The infection often results in significant morbidity (ill effects arising from a state of disease), striking people during their productive working years. According to WHO, women are two to four times more likely to become blind after becoming infected with trachoma than men. Often they cannot take care of themselves and their children when infected by the disease, especially when they are blinded. It is often the case that the oldest daughter, or another child, is taken out of school to tend to family needs. Because of the child's incomplete education, she/he is then unable to earn a living outside the family unit, and is restricted to providing care to the family. This vicious cycle continues in the future by keeping families, and sometimes entire villages, in poverty. Consequently, ITI reports that about $2.9 billion (in U.S. currency) is lost worldwide annually in human productivity because of trachoma.
IN CONTEXT: DISEASE IN DEVELOPING NATIONS
The CDC assists the World Health Organization in reducing the occurrence of trachoma, and asserts that major declines are now found in those countries associated with multifaceted control programs. The CDC reports that “WHO has initiated a global campaign for the elimination of blindness due to trachoma, that recommends a strategy including antibiotics, improved personal and community hygiene and sanitation, and surgery to correct trichiasis. Campaign challenges include: establishing surveillance for endemic trachoma, determining when mass treatment with antibiotics is necessary (i.e., retreatment), determining the effectiveness of improved hygiene and sanitation at preventing a resurgence of endemic disease, monitoring for adverse effects of mass treatment with antibiotics…”
SOURCE: Centers for Disease Control and Prevention (CDC), Coordinating Center for Infectious Diseases, Division of Bacterial and Mycotic Diseases.
Common complications of trachoma include scarring of the conjunctiva (membrane under the eyes) and cornea, eye lid abnormalities, turned-in eyelashes, vision reductions, and, in severe cases, blindness. The prognosis for each individual person depends on the severity of the disease, the treatment used to combat it, and the number of times the eyes are re-infected. Persons with trachoma who are treated with the proper drugs and in the early stage of the infection are much more likely to fully recover. Severe symptoms can be often eliminated but eyesight, once lost, cannot be regained.
See AlsoAntibacterial Drugs; Bacterial Disease; Chlamydia Infection; Handwashing.
BIBLIOGRAPHY
Books
Bellenir, Karen, ed. Infectious Diseases Sourcebook. Detroit, MI: Omnigraphics, 2004.
Parker, James N. The Official Patient's Sourcebook on Trachoma. San Diego, CA: Icon Health Publications, 2002.
Periodicals
Mabey, D.C., A. Foster, and A.W. Solomon. “Trachoma.” Lancet. 362 (9379) (July 2003): 223–229.
Web Sites
International Trachoma Initiative. “Trachoma is a hidden disease.” 2005 <http://www.trachoma.org/trachoma.php> (accessed April 2, 2007).
National Library of Medicine, National Institutes of Health. “Trachoma.” September 22, 2006 <http://www.nlm.nih.gov/medlineplus/ency/article/001486.htm> (accessed April 2, 2007).
Trachoma
Trachoma
Definition
Trachoma, also called granular conjunctivitis or Egyptian ophthalmia, is a contagious, chronic inflammation of the mucous membranes of the eyes, caused by the bacterium Chlamydia trachomatis. It is characterized by swelling of the eyelids, sensitivity to light, and eventual scarring of the conjunctiva and cornea of the eye.
Description
Trachoma is a disease associated with poverty and unhygienic conditions. It is most common in hot, dry, dusty climates in the developing world where water is scarce and sanitation is poor. Trachoma is the most common infectious cause of blindness in the world. It has two stages. The first stage is active infection of the conjunctiva by the bacterium C. trachomatis. The conjunctiva is the clear mucous membrane that lines the inside of the eyelid and covers the white part (sclera) of the eye. This stage is highly contagious.
Acquiring trachoma does not provide immunity against re-infection, so repeat infections are the norm in many communities where the disease circulates continuously among family members. The frequency of active infection peaks in children ages three to five. In some communities, as many as 90 percent of children under age five are actively infected.
The second stage involves damage to the cornea, the transparent covering of the front of the eye. After repeated infections, the eyelids swell and the eyelashes begin to turn inward so that they scratch the cornea every time the individual blinks. This scratching is painful, and it scars the cornea, eventually resulting in the cornea becoming opaque. Individuals are often blind by middle age. Repeated, extended, untreated periods of infection are required for blindness to occur. An occasional, treated infection does not result in blindness.
Transmission
C. trachomatis is spread through direct contact. Infected young children serve as a reservoir of infection. The bacteria are then transmitted by close physical contact with family members and other caregivers. The bacteria are also spread through shared blankets, pillows, and towels. The bazaar fly Musca sorbens lays its eggs in human feces that can be contaminated with trachoma bacteria. These flies pick up bacteria on their bodies and can transmit them to humans.
Certain conditions promote the spread of trachoma bacteria. These include:
- poor personal hygiene
- poor body waste and trash disposal
- insufficient water supply for washing
- shared sleeping space
- close association with domestic animals
Demographics
Trachoma is widespread and present in a high percentage of the population in many parts of Africa, Iraq, Afghanistan, Burma, Thailand, and Viet Nam. Pockets of high trachoma infection also exist in southern Mexico, eastern Brazil, Ecuador, North Africa, India, China, Siberia, Indonesia, New Guinea, Borneo, and in Aboriginal communities in central Australia. Although trachoma is rare in developed countries, it is occasionally found in the United States in some Native American communities and in parts of Appalachia.
The greatest risk for contracting trachoma is having a family member with the disease. Although the disease shows no gender preference, two to three times more women eventually become blind than men, probably because they are the primary caretakers of small children who are infected. The active stage of the disease is most prevalent in children ages three to five. Blindness is most common in middle age. The World Health Organization (WHO) estimates that as of the early 2000s, between 360 and 500 million people are affected by trachoma worldwide and that six million people are blind because of the disease. In some heavily infected areas, up to 25 percent of the population becomes blind from this infection.
Causes and symptoms
The early symptoms of trachoma include the development of follicles (small sacs) on the conjunctivae of the upper eyelids; pain ; swollen eyelids; discharge; tearing; and sensitivity to light. If the infection is not treated, the follicles develop into large yellow or gray pimples, and small blood vessels develop inside the cornea. In most cases, both eyes are infected. The incubation period is about one week.
Repeated infections eventually lead to contraction and turning-in of the eyelids. The eyelashes then scratch the corneas and conjunctivae, every time the individual blinks. This scratching leads to scarring of the cornea, eventual blockage of the tear ducts, and blindness.
When to call the doctor
U.S. parents should call the doctor if they notice any discomfort or discharge from their child's eye, especially if they have recently traveled in areas where trachoma is common.
Diagnosis
Diagnosis is based on a combination of the patient's history (especially living or traveling in areas with high rates of trachoma) and examination of the eyes. The doctor looks for the presence of follicles or scarring. In developed countries where laboratory facilities are available, the doctor takes a small sample of cells from the child's conjunctivae and examines it, following a procedure called Giemsa staining, to confirm the diagnosis. In underdeveloped countries where medical resources are scarce, diagnosis is made based on an examination only.
Treatment
The preferred treatment is the oral antibiotic azithromycin (Zithromax). This medicine has replaced treatment with other antibiotics (usually tetracyclines ), because only a single dose of azithromycin is required to clear the infection. Oral single dose treatment increases compliance. Everyone in the family should be treated at the same time, whether they show clinical signs of the disease or not, because transmission among family members is so common.
Individuals with complications from untreated or repeated infections require surgery. Surgery can be used for corneal transplantation or to correct eyelid deformities. It does not, however, prevent re-infection.
Prognosis
The prognosis for full recovery is excellent if the individual is treated promptly. If the infection has progressed to the stage of follicle development, prevention of blindness depends on the size of the follicles, the presence of additional bacterial infections, and the development of scarring. The longer the period of infection, the greater the risk of corneal scarring and blindness.
KEY TERMS
Conjunctivitis —Inflammation of the conjunctiva, the mucous membrane covering the white part of the eye (sclera) and lining the inside of the eyelids also called pinkeye.
Cornea —The clear, dome-shaped outer covering of the eye that lies in front of the iris and pupil. The cornea lets light into the eye.
Prevention
Trachoma is a preventable disease. Prevention depends upon good hygiene and public health. The WHO has developed a program called SAFE, which aims to prevent blindness caused by trachoma. The elements of the program are surgery, antibiotic treatment, facial cleansing and improved personal hygiene, and environmental improvements. Despite this prevention program, permanent gains in controlling trachoma have been elusive.
Parental concerns
In the United States, parents should check with the Centers for Disease Control (available online at <www.cdc.gov>) for advisories about the prevalence of trachoma if they are planning to travel with their children to underdeveloped countries.
Resources
BOOKS
Bailey, Robin. "Eye Infections in the Tropics." In Infectious Diseases, 2nd ed. Edited by Jonathon Cohen and William Powderly. St. Louis: Mosby, 2003.
O'Brien, Terrence P. "Conjunctivitis." In Conn's Current Therapy, 56th ed. Edited by Robert E. Rakel. Philadelphia: W. B. Saunders Co., 2004.
WEB SITES
Mabey, Denise, and Hugh Taylor. "Trachoma." eMedicine Medical Library, April 17, 2001. Available online at <www.emedicine.com/0ph/topic118.htm> Accessed August 1, 2004.
"Ophthalmologic Disorders: Trachoma." In The Merck Manual of Diagnosis and Therapy, 17th ed. Edited by Robert Berkow. Rahway, NJ: Merck Research Laboratories, 1999–2004. Available online at <www.merck.com/mrkshared/mmanual/home.jsp> (accessed October 18, 2004).
ORGANIZATIONS
Sight Savers International. c/o Chapel & York, PMB #293, 601 Pennsylvania Avenue, NW, Suite 900, South Building, Washington, DC 20004. Web site: <www.sightsavers.org>.
Tish Davidson, A.M.
Trachoma
Trachoma
Definition
Trachoma, which is also called granular conjunctivitis or Egyptian ophthalmia, is a contagious, chronic inflammation of the mucous membranes of the eyes, caused by Chlamydia trachomatis. It ischaracterized by swelling of the eyelids, sensitivity to light, and eventual scarring of the conjunctivae and corneas of the eyes.
Description
Trachoma is a major cause of blindness in the world. It is found in the Far East, as well as countries with desert climates. In the United States, it is most common among certain Native Americans and in parts of Appalachia. The infection is highly contagious in its early stages. Blindness results from recurrent untreated infections.
The conjunctiva is the clear mucous membrane that lines the inside of the eyelid and covers the white part (sclera) of the eye. Conjunctivitis is an inflammation of the conjunctiva.
Causes and symptoms
Trachoma is caused by C. trachomatis, a parasitic organism closely related to bacteria. It is transmitted by insects, by hand-to-eye contact, or by the sharing of infected handkerchiefs or towels. The incubation period is about a week.
The early symptoms of trachoma include the development of follicles (small sacs) on the conjunctivae of the upper eyelids, pain, swollen eyelids, a discharge, tearing, and sensitivity to light. If the infection is not treated, the follicles develop into large yellow or gray pimples, and small blood vessels develop inside the cornea. In most cases, both eyes are infected.
Repeated infections eventually lead to contraction and turning-in of the eyelids, scarring of the corneas and conjunctivae, eventual blockage of the tear ducts, and blindness.
Diagnosis
Diagnosis is based on a combination of the patient's history (especially living or traveling in areas with high rates of trachoma) and examination of the eyes. The doctor will look for the presence of follicles or scarring. He or she will take a small sample of cells from the patient's conjunctivae and examine them, following a procedure called Giemsa staining, to confirm the diagnosis.
Treatment
Treatment of early-stage trachoma consists of four to six weeks of antibiotic treatment with tetracycline, erythromycin, or sulfonamides. Antibiotics should be given without waiting for laboratory test results. Treatment may combine oral medication with antibiotic ointment applied directly to the eyes. A single-dose treatment with azithromycin is an alternative method. Tetracyclines should not be given to pregnant women or children below the age of seven years.
Patients with complications from untreated or repeated infections are treated surgically. Surgery can be used for corneal transplantation or to correct eyelid deformities.
Prognosis
The prognosis for full recovery is excellent if the patient is treated promptly. If the infection has progressed to the stage of follicle development, prevention of blindness depends on the severity of the follicles, the presence of additional bacterial infections, and the development of scarring.
Prevention
There are vaccines available that offer temporary protection against trachoma, but there is no permanent immunization. Prevention depends upon good hygiene and public health measures:
- seek treatment immediately if a child shows signs of eye infection, and minimize his or her contact with other children
- teach children to wash hands carefully before touching their eyes
- protect children from flies or gnats that settle around the eyes
- if someone has trachoma (or any eye infection), do not share towels, pillowcases, etc; Wash items well
- if medications are prescribed, follow the doctor's instructions carefully
Resources
BOOKS
Riordan-Eva, Paul, et al. "Eye." In Current Medical Diagnosis and Treatment, 1998, edited by Stephen McPhee, et al., 37th ed. Stamford: Appleton & Lange, 1997.
KEY TERMS
Conjunctivitis— Inflammation of the conjunctivae, which are the mucous membranes covering the white part of the eyeball (sclera) and lining the inside of the eyelids.
Cornea— The transparent front part of the eye that allows light to enter.
Ophthalmia— Inflammation of the eye. Usually severe and affecting the conjunctiva. Trachoma is sometimes called Egyptian ophthalmia.
Trachoma
TRACHOMA
Trachoma is a virulent form of conjunctivitis caused by Chlamydia trachomatis, a bacterial organism transmitted by flies that crawl into the eyes of small children. Direct transmission of the organism from fingers, damp towels, and other objects also occurs. Characteristically, reinfection is frequent in endemic regions; this leads to severe scarring and contractures, especially of the upper eyelid, and also causes blood vessels to invade the cornea, rendering it opaque. These effects of recurrent infection make trachoma a leading cause of blindness in those parts of the world where the condition is prevalent. These are predominantly poor, rural areas in hot, dry countries such as some nations in the Middle East and in arid regions of North Africa, India, Pakistan, and inland Australia.
Trachoma is responsible for about 6 million out of a total of 20 million cases of blindness worldwide, and it causes impaired vision in about 140 million people. Determined efforts have greatly reduced the incidence of new cases in the last two decades of the twentieth century, however. It is rare in industrially developed nations with good hygiene and effective fly control measures—such as screened windows. Trachoma is an exclusively human infection, so if vulnerable populations can be protected from exposure (e.g., if flies can be reduced or eliminated), transmission will cease and the infection can be prevented. These tactics have worked well in many regions, including among Australian Aborigines, where the prevalence was very high until control programs were established.
Control was achieved in Australia by an aggressive campaign led by Dr. Ida Mann, who devoted her life to this cause. Her methods comprised topical application of antiseptic and antibiotic eyedrops, disinfection and face washing, education about personal hygiene, and fly control programs. Initially this was a mass campaign, and it was reduced to individual case management as endemic conjunctivitis was brought under control. The same tactics have worked in the Middle East (e.g., among nomadic Bedouin populations in Saudi Arabia), and they are working well in endemic regions of India and Pakistan. The World Health Organization, with strong support from several foundations and nongovernmental organizations devoted to prevention of blindness, aspires to eliminate trachoma by 2020.
John M. Last
(see also: Vision Disorders )