Definition- a blinding chronic infective keratoconjunctivitis caused by repeated infections by Chlamydia trachomatis
• Greek – “rough”

Chlamydia serotypes
• A B Ba C – endemic trachoma
• D to K – genital tract disease, ophthalmia neonatorum, NGU, PID

• L1 L2 L2a L3 – lymphogranulorum venerum (LGV)

Lifecycle of C. trachomatis
• No cytochromes so cannot make ATP
• Obligate intracellular bacterium
• Exists in 2 forms
• Elementary body – infective, inert, 0.2 to 0.3μm
• Reticulate body – active, intracellular, 0.5 to 1.0 μm, binary fission, becomes an EB
• Enclosed in a vacoule called inclusion body
• 40 hour lifecycle, Incubation period 5-10 days

Disease transmission
• Infects conjunctiva – sticky discharge
• Attracts flies (Musca sorbens) the vector
• Flies prefer human faeces to animal dung
• Person to person transmission (4Fs)Flies,Foeces,Fingers,Fomites

Risk factors

• Lack of water
• Flies
• Cattle
• Exposed human feces
• Poor hygiene
• Crowding

WHO grading system

• Immune response –follicles (TF)
• Recurrent infection(TI)
• Scarring (TS)
• Trichiasis (TT)
• Corneal scar (CO)


  1. Mainly clinical
     FISTO
     torch and x2.5 loupe
     PPV falls with decreasing prevalence
  2. Laboratory methods – for research and special
     Conjunctival scrappings for inclusion bodies
     Tissue culture
     Direct Immunofluorescence test
     ELISA
     Nucleic acid amplification tests e.g PCR

Epidemiology – magnitude
• 2nd leading cause of blindness worldwide
• Leading infective cause of blindness
• 19% of blindness in Kenya
• 6 Million blind from corneal opacity

Trachoma is a disease of poverty
• Endemic in 48 countries in Africa and
Middle East
• Remote, arid, marginalised and displaced
• Pastoralists in E.Africa
• Poor access to water and sanitation

Focal disease
• Majority with active disease are <10 yrs
• Women and children
• Children and young livestock sleep
• Smoke and poor ventilation in manyattas

Disease control

• GET 2020
S- surgery for trichiasis
A- antibiotic distribution (TEO bd X 6wks,
azithromycin 20mg/kg)- mass Rx
F – face washing
E – environmental improvement
• Vaccine development

Principles of mass treatment
• Azithromycin clears ocular C.trachomatis
infection with one oral dose (20 mg/kg
body weight).
• If the baseline district prevalence of TF in
1–9year old children is ≥10%, then
trachoma is considered a public health

Treat all residents annually for 3 years.
• Then repeat the district survey.
• If the district prevalence of TF is still ≥10%
annual mass treatment should be
• If the prevalence is < 10%, surveys should
be conducted to determine the prevalence
at community level.

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