The problem started in Alison Samuel Morris' right eye. "Small dots" started blocking his field of vision. The size of the dots changed but they never really went away. He does not remember exactly how old he was when the dots appeared, although he knows he was in primary school and had to inch closer and closer to the blackboard to make out what the teacher had written.
Eventually Morris' family took him to see a doctor, where he received an uncertain diagnosis and a drug, the name of which he does not remember. His vision temporarily improved, but then the dots returned even worse than before.
His father was in the army and the family moved around what was then still southern Sudan. Morris went to three different doctors in three different town. But, he says, "every time my vision was decreasing, decreasing".
In March last year, with his vision almost completely gone, he saw a doctor in the Sudanese capital of Khartoum, where he was living at the time. He finally got the correct diagnosis: onchocerciasis, or river blindness.
He also received the devastating news that the disease had advanced so far that his vision could not be saved. He remembers the words the doctor told him: "This thing cannot be treated."
The parasitic disease is caused by the filarial worm, which is transmitted from person to person through the bites of infected blackflies. The adult worms can produce thousands of embryos, or microfilariae, which travel throughout the body, nesting in the skin, eyes and other organs.
When left untreated, river blindness causes persistent, itchy rashes, skin disfigurement and, as in Morris' case, permanent blindness.
There is no vaccine, but the disease can be treated with an annual doses of ivermectin. The drug kills off the microfilariae and can save the sight of some. But, like thousands of people across South Sudan, Morris did not know this.
"I knew before about OV," he says, using the shorthand name for the disease widely used in government awareness campaigns here. "I know your body can get a rash. But I did not know this thing can affect your eyes."
Health officials say they have the resources to eliminate the disease. But first they must make sure people know about it.
A neglected disease
The World Health Organization (WHO) groups onchocerciasis among the world's 17 neglected tropical diseases. The international health body estimates that nearly 18 million people worldwide are infected, although 99 percent of them are in Africa. It is the second-leading infectious cause of blindness in the world, behind trachoma.
"One of the few countries where the oncho is still endemic is South Sudan," says Dr Makur Matur Kariom, the undersecretary at the ministry of health. "I guess we have the heaviest load of all the cases across the world."
Most of the people ... don't know what causes their blindness.
It is impossible to determine just how many river blindness cases there are in South Sudan. The country's patchy healthcare system means that many patients fall through the cracks. But the ministry of health estimates that more than 4.1 million people – nearly half of the population – are at risk of contracting the disease. Communities clumped around fast-moving rivers, where the blackflies breed, are in particular danger.
An assessment of neglected tropical diseases in South Sudan by the UK's Department for International Development shows that onchocerciasis prevalence is high in five of the country's 10 states – especially in the western half of the country.
"But of late, there are cases reported in other places. Particularly in the southern part of the country, bordering Uganda," Kariom explains.
The government recently renewed its commitment to eliminate the disease by 2015, though Kariom admits meeting that goal is "unlikely". In a country with some of the world's worst health indicators, river blindness must compete with maternal health, malaria and other neglected tropical diseases for attention.
"Almost everything for us is a priority," Kariom says, while acknowledging that river blindness receives some special attention. "It takes a higher position in our priorities, because the morbidity they cause, it changes one's life forever. Like blindness. We have to prevent blindness. One way of doing it is eradicating one cause.”
Distributing ivermectin to everyone living in endemic areas once every six months for at least a decade could achieve this. Regular treatment reduces the amount of microfilariae in a community, which in turn reduces the reservoir of the disease to be transmitted by the blackflies.
Earlier this year Colombia became the first country in the world to eliminate river blindness through a combination of regular treatment and widespread education about the disease.
Through the support of the WHO's African Programme for Onchocerciasis Control (APOC) and non-governmental organisations, Kariom says South Sudan is ready to take on the first part of that challenge. He insists the country has the capacity to deliver the drugs for free to all who need them.
The challenge comes, he says, in explaining to people in endemic areas why they need to be taking the drugs and regularly reaching all of the people who need treatment.
Lack of awareness
Baranda March says the main problem is that people do not know they should be asking for the treatment.
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Colourful posters explaining how river blindness is transmitted and describing the disease's telltale symptoms surround March's desk at the Buluk Eye Clinic in Juba.
March has been an ophthalmic clinical officer for 25 years. He sees between 40 and 50 patients a day at the clinic, which is one of only four government-funded centres specialising in eye care in the entire country. He estimates that a quarter of his patients have onchocerciasis. The majority seek treatment only after their vision has started to deteriorate.
"Most of the people don't know so much about oncho," he says. "If you can ask people on the street 'what is causing your blindness?' They don't know. They don't know what causes their blindness. This needs more awareness."
Raising awareness presents a huge logistical challenge. South Sudan's poor road network makes it difficult to reach many of the rural communities where the disease is endemic. During the months-long rainy season the majority of the country is virtually inaccessible.
Health workers stationed at clinics across the country do as much as they can to educate people in their area, Kariom says, including recruiting community members to recognise early symptoms and to encourage people to go for testing. But, he acknowledges, there is a widespread "lack of information on the part of the patients. They may not know where to get the care they need. Others may think [the] traditional way of treating the disease is the best and may not seek the conventional healthcare".
Even after health officials engage in outreach, explain the disease and start treatment, they have to figure out how to continue reaching people regularly with the drugs. Because many communities are highly mobile, they are difficult to track year after year.
Levi Sunday Clement still thinks elimination is possible in South Sudan. He says the key is convincing people living in endemic areas to take more responsibility for requesting and sticking to treatment regimens.
If they are made more aware, they will realise how serious it is.
Clement is the chairman of Equatoria States Union of the Visually Impaired (ESUVI). He started to lose his sight to river blindness in 1988.
"We are usually catching fish in the river" near the village where he grew up in Western Equatoria state, he says. "At that time, I know this fly is there biting us. But this idea of river blindness or idea of transmitting this disease to close the eyes of us, we are not aware at that time. We are too small."
Like Morris, by the time Clement got tested and started treatment at Juba Teaching Hospital, it was too late. He was 23 years old when he permanently lost his vision.
"My friends, particularly girls, when they met me on the way, some of them started crying. Some of them started saying 'better you die'. People think you are so useless. You cannot do anything."
Being blind is a challenge anywhere, he says, but particularly in South Sudan where it is nearly impossible to continue in school or to find a job. Clement was able to learn braille at a Juba school that specialises in teaching the visually impaired and now has a job there teaching English and social studies.
His main passion is trying to prevent other people from losing their sight. Several times a year volunteers from ESUVI travel to the communities where river blindness is endemic to talk to people about the disease. They encourage them to stick to the regular doses of ivermectin and to seek out health workers if they are not visiting regularly enough.
He believes that once communities actually see people who have been affected by river blindness, it changes their attitudes.
"Some of these people are not taking this as a serious disease," Clement says. "If they are made more aware, they will realise how serious it is."