Rare Disease Mystery: Nodding Syndrome May Be Linked to Parasitic Worm

Rural Uganda village gathering

Caption: Village in the East Africa nation of Uganda
Credit: Centers for Disease Control and Prevention

In the early 1960s, reports began to surface that some children living in remote villages in East Africa were suffering mysterious episodes of “head nodding.” The condition, now named nodding syndrome, is recognized as a rare and devastating form of epilepsy. There were hints that the syndrome might be caused by a parasitic worm called Onchocerca volvulus, which is transmitted through the bites of blackflies. But no one had been able to tie the parasitic infection directly to the nodding heads.

Now, NIH researchers and their international colleagues think they’ve found the missing link. The human immune system turns out to be a central player. After analyzing blood and cerebrospinal fluid of kids with nodding syndrome, they detected a particular antibody at unusually high levels [1]. Further studies suggest the immune system ramps up production of that antibody to fight off the parasite. The trouble is those antibodies also react against a protein in healthy brain tissue, apparently leading to progressive cognitive dysfunction, neurological deterioration, head nodding, and potentially life-threatening seizures.

The findings, published in Science Translational Medicine, have important implications for the treatment and prevention of not only nodding syndrome, but perhaps other autoimmune-related forms of epilepsy. As people in the United States and around the globe today observe the 10th anniversary of international Rare Disease Day, this work provides yet another example of how rare disease research can shed light on more common diseases and fundamental aspects of human biology.

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Enlisting mHealth in the Fight Against River Blindness

CellScope Loa

When it comes to devising new ways to provide state-of-the art medical care to people living in remote areas of the world, smartphones truly are helping scientists get smarter. For example, an NIH-supported team working in Central Africa recently turned an iPhone into a low-cost video microscope capable of quickly testing to see if people infected with a parasitic worm called Loa loa can safely receive a drug intended to protect them from a different, potentially blinding parasitic disease.

As shown in the video above, the iPhone’s camera scans a drop of a person’s blood for the movement of L. loa worms. Customized software then processes the motion to count the worms (see the dark circles) in the blood sample and arrive at an estimate of the body’s total worm load. The higher the worm load, the greater the risk of developing serious side effects from a drug treatment for river blindness, also known as onchocerciasis.

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