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Trachoma

Overview

Trachoma is a bacterial ocular infection which is the most common cause of preventable blindness in the developing world. The obligate, intracellular bacterium, Chlamydia trachomatis, is the causative organism which causes development of chronic follicular keratoconjunctivitis. Complications due to repeated episodes progress to corneal scarring and potential loss of vision. Trachoma is believed to be endemic in 51 countries, with 232 million people living at risk of the disease. It is estimated that 8 million people have Trachoma-related visual impairment, of which 0.5 million are irreversibly blind. Trachoma is spread via personal contact and flies which have been in contact with the infection. The immune system is capable of clearing a single episode of the infection but populations in endemic countries experience continuous infections, which increases the rate of trachomatous conjunctival scarring. The majority of blinding trachoma occurs in poor areas of Africa where there is a lack of access to adequate water and sanitation.

 

Signs and symptoms

Trachoma usually affects both eyes and presents with:

  • Mild itching and irritation of eyes and eyelids

  • Discharge from the eyes containing mucus or pus

  • Inflammation of the eyelid

  • Photophobia

  • Ocular pain

  • Extreme dryness when lacrimal gland affected

 

WHO grading of trachoma

Causes

The bacterium Chlamydia trachomatis is easily spread through direct

person-to-person contact, shared towels/clothes/bedding, and flies which

have come into contact with the discharge from eyes or nose of an infected

individual. Children regularly infect mothers in developing countries.

 

Risk factors / at risk groups

Trachoma bacteria thrive in environments where there is:

  • Limited access to clean water

  • Limited access to washing and sanitation facilities

  • A large fly population

  • Limited access to health services

  • High level of overcrowding – e.g. many family members sleep in the same room

Non-environmental risk factors include:

  • Age – most common in children aged 4-6

  • Gender – risk of women contracting the disease is 2-6 times higher than that of men. Thought to be due to looking after young infected children.

Travellers from the UK are only at risk of developing trachoma if planning to live or work in very poor communities for a sustained period of time.

 

Diagnosis / microbiology testing

  • Physical diagnosis

  • Microscopy of Giemsa-stained specimens

  • Enzyme immunoassay

 

Treatment

Trachoma is simple to treat but due to the highly contagious nature and risk factors present in the endemic areas, risk of re-infection is high.

Surgery is required in cases where scarring of the eyelids has caused eyelashes to turn inwards. The procedure is carried out under local anaesthetic. With visual impairment, cornea transplants may be effective in restoring some vision but this is rare to be carried out in the majority of areas due to limited healthcare facilities.

For early stages of Trachoma, treatment involves tetracycline eye ointment or oral azithromycin. A single dose of azithromycin given stat has proved most effective but it is more expensive and so may not be first line in some endemic countries. WHO recommends that the entire community should be treated with a single dose of azithromycin if 10% or more children present with symptoms of Trachoma.

 

Vaccines/ preventative measures

There is currently no vaccine available.

Preventative measures include:

  • Improving access to clean water and sanitation facilities

  • Reducing the local fly population

  • Regular face washing to remove contagious discharge

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