Today in my genetics class we started to discuss an extremely interesting and unique example of neurodegenerative disease that gave rise to the identification of a novel infectious agent. The disease is called kuru, previously called the “laughing death”, and was seen only in the Fore people of Papua New Guinea, particularly among the women and children. The symptoms of kuru include trembling, excessive laughing, and falling over. Eventually, the trembling leads to total loss of motor control and the patient essentially becomes locked in his or her own body. The condition is lethal in all cases. The Fore people thought kuru was the result of evil sorcery practiced by neighboring tribes, which led to increased violence between villages. Enticed by the mystery of the disease, scientists from Australia, the U.K., and the U.S. traveled to Papua New Guinea to study the epidemic. Over time, the scientists discovered that kuru was being spread through the practice of cannibalism within the Fore tribe, especially the consumption of brain and spinal cord tissue. Cannibalism was a traditional part of the mortuary practices of the Fore people. After an individual passed away, the closest relatives would cook and eat the body. However, only the women and children in the family were included in this practice, which explained why the disease was concentrated in the women and children.
This was the first neurodegenerative disease to be found transmissible between humans. This conclusion was also found to apply to diseases such as Mad Cow Disease, the human form of Mad Cow, variant Creutzfeldt-Jakob disease, and regular CJD. The spread of these diseases was attributed to a new form of infectious agent, the prion, a misfolded protein that enlists the misfolding of other proteins and eventually tears holes in neural tissue.
What I thought was particularly interesting was that these diseases were found to have incubation periods spanning over twenty years with some people experiencing shorter incubation periods than others. Currently, scientists are conducting genetic analysis of kuru experiencing populations to determine if there is a genetic component to susceptibility to these diseases. Even today, people contract variant CJD by ingesting contaminated beef. Could it be possible that there are people walking around with dormant prions in their brains? What determines, if and when these infectious agents will make themselves known? Since these are strictly neurological diseases, I would be interested to see (when we develop the technology of course) if there are connectome differences between individuals who got the disease early as opposed to late and between those who got the disease compared to those who did not even though they were involved in the cannibalistic rituals. Could certain brain wiring patterns make the individual more resilient to the spread and activity of prions?
In the end, the moral of the story is don’t eat people. It’s bad for your brain.
Here’s a link to the documentary if you’re interested in learning more: Kuru: The Science and the Sorcery