Trachoma – Epidemiology, Symptoms, and Prevention.

Definition

Trachoma is a contagious bacterial infection which affects the conjunctival covering of the eye, the cornea, and the eyelids. It is often associated with poverty and lack of proper hygiene. Trachoma is caused by the Chlamydia trachomatis bacteria and is essentially totally preventable and curable. It is the leading infectious cause of blindness in the world.

 

Trachoma eye

History

The disease is one of the earliest known eye afflictions, having been identified in Egypt as early as 15 B.C. Its presence was also recorded in ancient China and Mesopotamia. Trachoma became a problem as people moved into crowded settlements or towns where hygiene was poor. It became a particular problem in Europe in the 19th century. After the Egyptian Campaign (1798–1802) and the Napoleonic Wars (1798–1815), trachoma was rampant in the army barracks of Europe and spread to those living in towns as troops returned home. Stringent control measures were introduced and by the early 20th century, trachoma was essentially controlled in Europe, although cases were reported up until the 1950s. Today, most victims of trachoma live in underdeveloped and poverty-stricken countries in Africa, the Middle East, and Asia.

Epidemiology of trachoma

Trachoma is endemic in parts of Africa, Asia, the Middle East, Latin America, the Pacific Islands, and aboriginal communities in Australia.Worldwide, an estimated 229 million people in 53 countries live in trachoma-endemic areas. In hyperendemic areas, most members of nearly all families may have active disease. When the overall community prevalence decreases to around 20%, active disease is clearly seen to cluster in families. In 1 of 5 families, most children have active trachoma (as opposed to 1 in 5 children in most families). This clustering becomes more apparent in communities as the prevalence decreases.

Types of trachoma

Acute trachoma

It is frequently found in children who are dirty, dusty and unhealthy. The symptoms include painful eyes, swollen eyelids, watery discharge from the eyes and itching of the eyes with ear, nose and throat infection. It usually affects one eye and gradually spreads to both the eyes.

Recurring trachoma

If poor hygiene persists the person gets affected again and again.

Chronic Trachoma

It causes inward turning of the eyelid such that the eye lashes rub against the cornea .Gradually the symptoms persist and instead of resolving lead to chronic trachoma and leads to blindness between the age of 30 to 40 years if left untreated. If it does not lead to blindness, it leads to scarring of the of the cornea of the eye.

Risk factors

Factors that increase your risk of contracting trachoma include:

• Poverty. Trachoma is primarily a disease of extremely poor populations in developing countries.
• Crowded living conditions. People living in close contact are at greater risk of spreading infection.
• Poor sanitation. Poor sanitary conditions and lack of hygiene, such as unclean faces or hands, help spread the disease.
• Age. In areas where the disease is active, it’s most common in children ages 4 to 6.
• Sex. In some areas, women’s rate of contracting the disease is two to six times higher than that of men.
• Flies. People living in areas with problems controlling the fly population may be more susceptible to infection.
• Lack of latrines. Populations without access to working latrines — a type of communal toilet — have a higher incidence of the disease.

Causes of trachoma

• Trachoma is caused by certain subtypes of Chlamydia trachomatis, a bacterium that can also cause the sexually transmitted infection chlamydia.
• Trachoma spreads through contact with discharge from the eyes or nose of an infected person. Hands, clothing, towels and insects can all be routes for transmission. In developing countries, eye-seeking flies also are a means of transmission.

Symptoms

The major symptoms or signs of the initial stages of trachoma consist of:

• Irritation and mild itching of the eyelids or eyes
• Drainage from the eyes contains pus or mucus
• As this disease progresses, trachoma symptoms begin to include:
• Blurred vision
• Marked sensitivity to light referred to as photophobia
• Pain in the eye

Young children are most susceptible to this disease but the infection normally advances gradually and the most painful signs or symptoms normally will not develop until adult hood.

What are complications of trachoma?

• Trachoma causes irritation of the eye, starting with simple redness of the eye and lids, progressing to inward turning of the lids and irritation and scarring of the cornea, which may then progress to an opaque cornea resulting in blindness. These complications are avoidable with adequate diagnosis and treatment.
• With development of the later stages of trachoma with scarring of the lids and conjunctiva, vision is often decreased to the point where the individual is no longer able to work, resulting in disruption of the family. Children drop out of school to take care of a parent with blindness and the family may have severe economic problems.
• Because of profound visual disturbance or blindness, there may be an increased number of related injuries or even accidental death.

Diagnosis and test

• Although there are bacteriologic and other tests available, trachoma is commonly diagnosed by examining the eyes and eyelids of the patient. In the rare cases seen in developed countries, the diagnosis is usually by the ophthalmologist.
• Sample of bacteria from your eyes to a laboratory for testing. But lab tests aren’t always available in places where trachoma is common.
• However, in the third world, ancillary personnel are very capable of being trained to make this diagnosis. Trachoma should be suspected from the history and symptoms. It then can be confirmed by an examination which can be performed within the community without the aid of sophisticated office equipment.
• If equipment is available, the vision is measured and the eye is inspected with a slit lamp (bio microscope), with which characteristic changes in the lids, tear film, conjunctiva, and cornea can more easily be seen.

Treatment and medications

• The treatment is relatively simple. A single oral dose of antibiotic is the preferred treatment, plus making safe water available and teaching simple cleanliness. Because of cultural differences and widespread poverty in endemic areas, this regimen is difficult to implement on a universal scale.
• The World Health Organization (WHO) developed the SAFE strategy.

                                                      S = surgical care

                                                      A = antibiotics

                                                      F = facial cleanliness

                                                      E = environmental improvement

• Treatment involves screening communities for the presence of trachoma in children 1-9 years of age. When over 10 % are found to have clinical disease, the entire community is treated with antibiotics. In areas with less disease, only targeted groups are treated.
• Due to the contagiousness of trachoma, it is necessary to treat all who might be in contact with the infected individuals.
• The actual treatment is the onetime use of use of azithromycin (Zithromax) pills (currently the treatment of choice) or the topical use of 1% tetracycline (Achromycin) ointment.
• When trachoma has progressed to inward-turning of the lashes, surgery is necessary to correct this and prevent the lashes from scarring the cornea. Performance of this surgery can be taught to nurses or other medical personnel.
• If significant corneal scarring already exists, corneal transplantation surgery may be required, which should be performed by an ophthalmologist.

Can trachoma be prevented?

Maintaining good hygiene and sanitation are essential to prevent this disease of the developing countries which has been eradicated from the developed countries. The steps include:

• Avoid physical contact with a person suffering from trachoma
• Personal cleanliness, especially of face and hands is important.
• Washing hands and face frequently with soap and water is important even in children who are already infected to prevent re-infection.
• Keep separate towels, handkerchiefs and linens for each member of the family.
• Wash hands after handling domestic animals.
• Keep the food covered and use latrines and toilets for defecation to prevent breeding of flies.
• Avoid crowded places.