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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Creative Minds: The Worm Tissue-ome Teaches Developmental Biology for Us All

C. elegans

Caption: An adult Caenorhabditis elegans, 5 days
Credit: Coleen Murphy, Princeton University, Princeton, NJ

In the nearly 40 years since Nobel Prize-winning scientist Sydney Brenner proposed using a tiny, transparent soil worm called Caenorhabditis elegans as a model organism for biomedical research, C. elegans has become one of the most-studied organisms on the planet. Researchers have determined that C. elegans has exactly 959 cells, 302 of which are neurons. They have sequenced and annotated its genome, developed an impressive array of tools to study its DNA, and characterized the development of many of its tissues.

But what researchers still don’t know is exactly how all of these parts work together to coordinate this little worm’s response to changes in nutrition, environment, health status, and even the aging process. To learn more, 2015 NIH Director’s Pioneer Award winner Coleen Murphy of Princeton University, Princeton, NJ, has set out to analyze which genes are active, or transcribed, in each of the major tissues of adult C. elegans, building the framework for what’s been dubbed the C. elegans “tissue-ome.”

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Snapshots of Life: A Kaleidoscope of Worms

C. elegans

Credit: Adam Brown and David Biron, University of Chicago

What might appear to be a view inside an unusual kaleidoscope is actually a laboratory plate full of ravenous roundworms (Caenorhabditis elegans) as seen through a microscope. Tens of thousands of worms (black), each about 1 millimeter in length at adulthood, are grazing on a field of bacteria beneath them. The yellow is a jelly-like growth medium called agar that feeds the bacteria, and the orange along the borders was added to enhance the sunburst effect.

The photo was snapped and stylized by NIH training grantee Adam Brown, a fourth-year Ph.D. student in the lab of David Biron at the University of Chicago. Brown uses C. elegans to study the neurotransmitter serotonin, a popular drug target in people receiving treatment for depression and other psychiatric disorders. This tiny, soil-dwelling worm is a go-to model organism for neuroscientists because of its relative simplicity, short life spans, genetic malleability, and complete cell-fate map. By manipulating the different components of the serotonin-signaling system in C. elegans, Brown and his colleagues hope to better understand the most basic circuitry in the central nervous system that underlies decision making, in this case choosing to feed or forage.

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Snapshots of Life: NIH’s BioArt Winners

Brick wall adorned with poster-sized prints of winning photos

Credit: FASEB

If you follow my blog, you know that I like to feature spectacular images that scientists have created during the course of their research. These images are rarely viewed outside the lab, but some are so worthy of artistic merit and brimming with educational value that they deserve a wider audience. That’s one reason why the Federation of American Societies for Experimental Biology (FASEB) launched its BioArt contest. Of the 12 winners in 2013, I’m proud to report that 11 received support from NIH. In fact, I’m so proud that I plan to showcase their work in an occasional series entitled “Snapshots of Life.” Continue reading to see the first installment—enjoy! Continue reading