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Nodding disease baffles experts

May 2011
Pader District, Uganda Want to embed this video?
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If you have seen these cases in their homes, you would cry when you look at them.”
Here in a hot, dusty part of northern Uganda, children are falling victim to a mysterious disease that has confounded health officials.

It’s known loosely as “nodding disease” and almost every family in the village we’ve come to see in Pader District has at least one child suffering from it.

Nine year old Vicky Ayaa began showing symptoms on the day we arrived.

The disease gets its name from its most noticeable symptom. The young girl appears to be nodding off. Her eyes begin to close and her head drifts downwards as if she’s falling asleep, yet she’s not tired and doesn’t want to lose focus.

Every few seconds her head jolts upwards and her startled gaze is upon us, then the eyelids become heavy and she fades again.

Over time, Vicky will likely get much worse, falling down and injuring herself, losing cognitive ability and experiencing stunted growth.

School often becomes too difficult for many children with nodding disease and they drop out. Indeed many of them die young.

They can fall into cooking fires when losing consciousness. Drown during a seizure. Die of opportunistic infections that strike the malnourished. Or they may simply be abandoned by their families.

“Within the communities some of the parents have thrown their children onto the streets," says Dr. Emmanuel Tenywa, the World Health Organization’s team leader in the area. "They say they are tired. For how long will they be looking after these children? If you have seen these cases in their homes, you would cry when you look at them.”

When Vicky recovers from the nodding bout, she’s able to fetch water, but she must be watched closely.

Her mother weeps behind a nearby tree, distraught because she has only two children, and now, both of them have the condition.

William Oyet, a government health officer in the district, says this family’s case is typical. “It can start anywhere, and the whole people in the village are worried because any time, any day, your kid will start nodding.”

Experts from the World Health Organization and the Centers for Disease Control and Prevention in Atlanta have been trying to find the cause of this condition. So far they’ve come up empty-handed.

Dr. Scott Dowell, from the CDC’s Division of Disease Detection & Emergency Response, led an investigation in the area. He says they’re not only baffled by the cause of the disease. They can’t determine why it only preys on children. “It really is very tightly clustered between five and 15 years of age,” he says. “In the study we did in northern Uganda 93% of kids were in that age window and I don’t know why that is.”

Throughout the village, some parents of the children are desperate.

As cruel as it seems, one mother keeps her son, David Okot, tied at the ankle with a rope so he can’t wander off.

David first showed symptoms of nodding disease in 2003. He’s 15 years old now, but looks much younger. He spends most of his days, angry and confused, tethered to a post on his family’s hut.

Since he became afflicted with the condition, David has developed a mental disability. He hasn’t spoken clearly for two years. Some villagers are frightened by him and consider him dangerous.

And these dangers, and fears, are in evidence almost everywhere you turn in the village.

William Oyet, the local health official, shows us two more children who appear to be about six or seven years old. “Monica is 13 years old and when you look she has stunted growth and cannot go to school, cannot do anything.”

The other child wears only a pair of faded shorts. His face and distended belly are covered in saliva. “He’s 11 years old,” says Oyet. “When you see the syndrome it has affected the growth. He cannot do much. The head, the saliva is all over the body and he’s really malnourished.”

Indeed many of the affected children are malnourished because eating food seems to spark bouts of nodding and sometimes seizures. Epilepsy drugs have been used to control the episodes, but they do not cure the condition, for which the key question is: what's causing it?

“I wish we knew. It’s really frustrating,” says the CDC’s Dowell. “We know now from the most recent investigation that it is a brain disease. There’s clearly something wrong with the brains of these kids who have it. We’ve documented by MRI scans that the brains have some atrophy and by EEG that the brain waves are abnormal. In fact some of the kids with nodding have almost continuous seizure activity although they appear fairly normal.”

But the elusive question remains. “We understand the path of physiology of nodding but we still don’t know what causes it,” says Dowell.

The WHO’s Dr. Emmanuel Tenywa says there are other clues. For example, he says all the affected children have onchocerciasis, a parasitic condition that can cause blindness.

“I think that gives us a bit of a starting point,” says Tenywa. “But the whole issue is now if you are infected with onchocerciasis, how does it cross the brain barrier to go into the brain, and what damage does it exactly do? These are the things which we are trying to understand.”

But onchocerciasis is common in many African countries, so why doesn’t nodding disease appear elsewhere? So far it’s only been found in small pockets of northern Uganda, Sudan and Tanzania, but the number of cases is growing. That’s raising fears that it could spread to more areas, sparking a greater sense of urgency in the health community.

But for the people in this village in northern Uganda, the sense of urgency couldn’t be any greater. To them it’s not a medical mystery. It’s a blight that’s picking off their children, one by one.
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