The research project, which involved 2.6 million participants in 29 different countries, over a 3-year period, was made possible by the use of smartphone technology to help collect, log and transmit data from surveyors operating around the world.
Dr. Caroline Harper, CEO of Sightsavers, says:
“The biggest infectious disease mapping exercise in history, ‘The Global Trachoma Mapping Project,’ has been completed within agreed timescales and budget. Funded by the UK government, in partnership with the US and WHO [World Health Organization], this creates a lasting platform which will underpin the drive to eliminate blinding trachoma, and will also contribute to efforts to eliminate other neglected tropical diseases.”
She adds that it “demonstrates how critical accurate data is in the battle to eliminate diseases, and has been a tremendous exercise in collaboration and the use of mobile technology.”
Trachoma is the leading infectious cause of blindness in the world, impairing the vision of around 2.2 million people, of whom 1.2 million are irreversibly blind. It is a health problem in around 51 countries, including Asia and the Middle East, with Africa carrying the bulk of the burden.
The disease is mostly prevalent in poor, crowded communities with limited access to clean water and sanitation. In its initial stages, it mainly passes between children aged 1-5 years and the women who care for them.
Trachoma responsible for 3% of world’s blindness
3-year old Anwar, from the Sudan, was one the millions of people surveyed for the study. Like many people living at risk of the disease, Anwar’s mother was unaware of the condition.
“I have six children – the oldest is 24 years and is a girl and Anwar, who is 3, is the youngest,” she says. “Today the people came to survey all of our children and they found that Anwar has got stage 1 trachoma. I don’t know what this disease is, but the grader has explained it to me.”
Anwar’s family were all examined by grader Dr. Jasser, of the Trachoma Mapping Team. “We have found that Anwar has got trachoma.” says Dr. Jasser. “It is a bacterial infection that is transmitted by flies so his mother needs to keep Anwar’s face clean and give him antibiotic ointment.”
Dr. Jasser further describes the conditions in which the family lives:
“The environment is very overcrowded – there are five other children in the family. They have a lot of animals like goats and chickens living around in the same environment as the children so it is not a clean environment. There are a lot of flies and a lot of poverty. After they use the ointment for 6 weeks, the condition should clear up, but the mother will need to also clean his face.”
Trachoma is responsible for 3% of the world’s blindness. It is caused by the bacterium Chlamydia trachomatis and is thought to be spread through personal contact (hands, clothing) and by flies that have been in contact with discharge from the eyes or nose of an infected person.
After repeated infection, it can develop into trichiasis – where the eyelids turn in and the lashes scrape the eyeball, causing great pain and ultimately leading to permanent blindness.
Complete map of disease prevalence from smartphones
Ethiopia has the world’s highest trachoma prevalence, with an estimated 50 million people living in endemic areas.
Yabeiywok Sema, who is 60 years old and lives with her husband and grandchildren, was diagnosed with trichiasis by the team of mappers who visited her house.”I had constant pain in my eye and could see less and less which made farming, my main source of income, difficult,” she says.
“I didn’t visit the health clinic because I didn’t realize how serious the infection was or that free surgery was available. At times the pain was very bad and I would rub my eyes to try to make it stop.” Yabeiywok was referred to a local health clinic and had surgery 1 week later to stop her eyesight from deteriorating further.
Over the course of the 3-year study, more than 550 teams of trained surveyors, including ophthalmic nurses and other government eye health care workers, visited millions of people in sample households in the most remote locations of 29 countries, including Chad, Eritrea, Pakistan, Papua New Guinea, Solomon Islands, Colombia and Yemen.
The teams conducted eye examinations and used mobile phones and tablets to record their findings, which were then sent to a data center in Atlanta, GA. There, the information was cleaned and analyzed before being sent to local governments for review, approval and use.
Having a complete map of the disease’s prevalence means that ministries of health in endemic countries have the evidence needed to focus preventative and treatment strategies to tackle the neglected tropical disease.
The WHO approve a variety of measures designed to tackle the disease including interventions of surgery, antibiotics (through mass drug administration), face-cleanliness and environmental improvements (like sanitation).
As a result of the research, health departments are now equipped with accurate information to help deploy targeted interventions.