Two weeks ago, on 20th April, the World Health Organization (WHO) announced that Gambia had eliminated trachoma as a public health problem. Although this is great news for the global health community, to fully understand the relevance of it, it is crucial to talk about trachoma as a Neglected Tropical Disease (NTD) and about NTDs themselves still posing one of the greatest challenges for health equity.
Neglected Tropical Diseases: What Are They and Why Are They Important?
The term Neglected Tropical Disease includes all kinds of parasitic, viral, and bacterial diseases that affect more than 1 billion people worldwide, predominantly in tropical and subtropical areas. The 20 diseases and disease groups currently considered NTDs by the WHO have a singular commonality: their disproportionate and devastating impact on impoverished communities. This means that, although they impose a human, social and economic burden in all countries in the world, this burden is particularly large in low-income countries and the most disadvantaged communities in middle-income countries. Thousands of people die from illnesses like rabies, dengue, and snakebite envenoming each year. Moreover, lack of timely access to affordable treatment leaves hundreds of millions severely disabled, disfigured, or debilitated, often resulting in social exclusion, stigmatization, and discrimination.
As a result, these pathologies have the potential to act as tracers for identifying disparities in progress towards both universal health coverage and equitable access to high-quality health services. That is why successful interventions against NTDs are not only relevant for the specific targets set in the Sustainable Development Goal (SDG) 3- “Ensure healthy lives and promote well-being for all at all ages”-. They go beyond health and contribute to achieving other goals. On the one hand, wider provision of clean water, sanitation and hygiene (WASH) helps control many NTDs. On the other hand, having them under control plays a role in alleviating poverty and hunger, enabling people to pursue an education and lead productive working lives, and promoting equality.
Let’s Talk About Trachoma
Trachoma is an eye disease caused by Chlamydia trachomatis, an obligate intracellular bacterium. It is transmitted through personal contact of hands or clothes and by flies that have been in contact with discharge from the eyes or nose of an infected person. In endemic areas, inflammatory trachoma- which requires topical or systemic treatment depending on the seriousness- is very common among pre-school children and infection becomes less frequent and shorter with increasing age. An individual’s immune system can clear a single episode, but re-acquisition of the bacteria is frequent in endemic communities, which leads to scarring of the inner side of the upper lid, resulting in inward turning of the eyelid margin with the lashes touching the globe. This is trachomatous trichiasis, a painful disease that, without surgical treatment, leads to irreversible blindness.
Approximately 1.4% of all blindness worldwide is caused by C. trachomatis, turning it into the leading infectious cause of blindness. Trachoma is a public health problem in 44 countries, 29 of them on the African continent, resulting in 1.9 million people being visually impaired and 2.5 million requiring surgery according to data from 2019. Even though infection affects mainly children, long-term consequences develop years after and affect mainly adults. Among the older population, women are up to 4 times more likely than men to be affected by blinding complications due to their closer contact with children. Furthermore, risk factors include poor hygiene, overcrowded households, and inadequate access to water and sanitation facilities, which places the most vulnerable populations at the highest risk.
Towards Elimination: How to End Trachoma?
In 1996, WHO launched an Alliance for the Global Elimination of Trachoma by 2020 (GET2020), which aimed to eliminate trachoma as a public health problem from all the 66 countries withstanding its burden. The targets were not achieved and new ones were set for 2030 and gathered in a roadmap with all the other NTDs’ elimination goals. The WHO aims to increase the number of countries validated for elimination as a public health problem from 10 in 2020 to 43 in 2025 and 66 (100% of them) in 2030. To meet the goal, and because this is an epidemiologically complex disease, a specific elimination strategy has been developed and is followed by all countries aiming for elimination. It is called the SAFE strategy and includes 4 coordinated and simultaneous approaches:
- Surgery to treat trachomatous trichiasis, the blinding stage of the disease.
- Antibiotics to clear infection, particularly through mass drug administration programmes.
- Facial cleanliness.
- Environmental improvement, primarily by assuring better access to water and sanitation.
So far, 10 countries have successfully eliminated trachoma as a public health problem with Gambia being the last one in April 2021 and only the second one in the African continent. Progress is being made, but enhanced commitment is needed for it to be sustained and in order to avoid the most feared risk: the possibility of recrudescence.