Mapping the world’s trachoma hotspots

When Iyabo Dolarin’s trachoma mapping team conducts surveys in Nigeria’s Kaduna State, they begin with a ritual: They go to the centre of the community and spin a bottle on the ground to determine which household will first be checked for signs of this painful and disabling disease.

The activity always attracts a crowd. “When they see it, they laugh,” said Dolarin, an eye nurse. “But we make them understand that, although it’s not every house we visit… we are not choosing one and leaving another. And we explain that after we finish mapping, if anyone has eye disease, we will see them later.”

The mapping project - led by the charity Sightsavers, with funding from the UK’s Department for International Development (DFID) and support from other agencies - is part of an ambitious plan to eliminate trachoma, a bacterial infection spread by flies that causes blindness.

“We had been mapping slowly, but now it’s all about speed,” Simon Bush, the Sightsavers director for neglected tropical diseases, told IRIN. “The international community has set out to eliminate blinding trachoma by 2020. We have to get the mapping completed and start the treatment programme by 2015, otherwise we are just setting ourselves up, once again, to fail.”


The mapping project sets out to determine the prevalence of disease in each district.

In places with low prevalence, where fewer than 10 percent of children have trachoma, the World Health Organization recommends focusing efforts on hygiene to prevent the disease - for example, building latrines and encouraging face washing. Places with high prevalence, where more than 10 percent of children have trachoma, receive a more aggressive intervention, including mass treatment with antibiotics.

The protocol is called SAFE, which stands for: Surgery (for those whose eyes are already damaged), Antibiotics (to treat those infected), Facial cleanliness, and Environmental improvement (to prevent the spread of the disease).

The bacterium itself, Chlamydia trachomatis, is unlikely to be eradicated the way smallpox was, but the harm caused by the disease can be minimized. Trachoma causes damage over time, with repeated infections in childhood causing eyelid scars that turn the lashes inwards. The lashes scratch the eye, leading to blindness. The aim, therefore, is to reduce incidence of the disease and to treat cases before scarring and damage take place.

"We estimate that there are around eight million people needing surgery, some three million of them in Africa. And if we don’t operate on them, they will go blind."

“If you implement SAFE over five years, you will eliminate blinding trachoma,” Bush said. “Ghana and the Gambia have already reached the elimination stage, where trachoma is no longer a serious public health concern.”


Those whose eyes are already damaged can be treated with surgery.

“The backlog,” said Bush, “is my constant worry. We estimate that there are around eight million people needing surgery, some three million of them in Africa. And if we don’t operate on them, they will go blind.”

But to treat so large a caseload, many more health workers will have to be trained in the surgical procedure - and surgeons of any kind are in short supply in the countries most affected by trachoma.

“It is important that we don’t divert attention from things even more important than trachoma,” the project’s chief scientist, Anthony Solomon, of the London School of Hygiene and Tropical Medicine, told IRIN. “Trachoma causes blindness, but, finally, it doesn’t kill you. I wouldn’t want it to stop obstetricians doing caesareans or other surgeons draining liver abscesses.”

But Solomon says others can be trained in the procedure: “We are also going to be training eye nurses to operate, and they will do it in addition to their other duties.”

Mapping tool

The mapping project collects data with a smartphone app. Collectors like Dolarin, the eye nurse, take global positioning system (GPS) readings for every household surveyed.

Soloman, who worked on the app’s development, says organizers have been pleased with it: “It’s very robust because the data is stored on the phone’s micro SD card. If you drop the phone out of a window, run over it in a car or drop it in the river, we can recover the card, and the data will still be readable.”

Dolarin says the tool is a great improvement over old-fashioned disease mapping. “It’s much better, much faster. There’s no need for moving about with lots of papers, and immediately after we do the work we send the result, so it doesn’t waste time at all.”

She has also been pleased to find fewer trachoma cases in the areas she surveyed. “When we did this before, there were many [cases]. The living condition of the people then was very bad. Most of the communities didn’t have boreholes. Now, most communities have them, so there is water now, people are cleaner, and there’s much less trachoma.”