Welcome back to “Shedding Light on NTDs”. This week, we will be discussing the leading infectious cause of preventable blindness, a neglected tropical disease known as trachoma. It is a disease caused by the bacterium Chlamydia trachomatis and affects approximately 110 million people worldwide [1]. Trachoma is found in 31 countries globally, with Ethiopia having the highest known burden of disease [2].
Trachoma is commonly spread through direct contact with an infected person, especially within a single household [3]. It is common for transmission to occur from sharing items, like pillows or towels, but in rural areas, transmission can also occur from flies [4].Young children have the highest risk of infection, and as a result, their adult female caregivers are often more at risk than their male counterparts [4].
An individual typically can recover from a single infection, but in endemic areas, high exposure to trachoma results in frequent infections [3]. Repeated infections over a lifetime with trachoma cause the disease to progress from treatable conditions to incurable blindness [3]. With the progression of disease, the upper eyelid turns inward, which causes eyelashes to rub the eyes, leading to immense pain and scarring, eventually causing blindness [3]. It is estimated that more than two million people worldwide are currently blind or suffering from severe disability due to advanced stage trachoma [1].
The World Health Organization (WHO) classifies trachoma infections in five stages [3]:
Stage 1: Trachomatous inflammation-follicular, which is treatable with topical medications
Stage 2: Trachomatous inflammation-intense, where both topical and systemic treatments are used
Stage 3: Trachomatous scarring, where corneal scars are visible and may obscure blood vessels
Stage 4: Trachomatous trichiasis, where eyelid surgery is required
Stage 5: Corneal opacity, where irreversible blindness occurs.
As a neglected tropical disease, trachoma enhances the cycle of poverty. In endemic regions, poor hygiene, crowded households, water shortages and sanitation issues are major environmental risk factors that are common amongst the poorest population [3]. If contracted, the damage to sight prevents those infected from working, furthering the physical and economical suffering as the disease transmits from one generation to the next [4, 5]. Often, trachoma is referred to as both a symptom and cause of poverty [1].
WHO has targeted trachoma for elimination by 2020 through a multidimensional public health strategy called S.A.F.E., which stands for [4]:
Surgery to correct trichiasis
Antibiotics
Facial cleanliness and,
Environmental improvements for water and sanitation cleanliness
Through the dedicated efforts of the world’s leading public health organizations, the ultimate goal is to keep all cases of preventable blindness from occurring. In 2018, Ghana became the first sub-Saharan African country to be validated by the WHO as being disease-free of trachoma following a twenty-year campaign, which led to the elimination of trachoma in Cambodia, Laos, Mexico, Morocco, Oman, Nepal and now, Ghana [2, 6]. While this work is certainly not complete, every step of progress for eliminating the disease means one less person will have to suffer from preventable blindness.
Sources:
[1] http://www.who.int/blindness/causes/WASHing_away_blinding_trachoma.pdf
[2] https://www.cartercenter.org/health/trachoma/index.html
[3] http://www.who.int/trachoma/disease/en/
[4] https://www.cdc.gov/healthywater/hygiene/disease/trachoma.html
[5] http://www.trachomacoalition.org/about-trachoma
[6] https://www.nytimes.com/2018/07/16/health/trachoma-blindness-nepal.html