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The Eternal Itch: Dante’s Eighth Circle of Hell

The Eternal Itch: Dante’s Eighth Circle of Hell

Onchocerciasis or River Blindness is caused by a parasite endemic to Africa that is transferred to a person by the bite of a blackfly. The parasite matures in the host within a year, and then reproduces up to a thousand tiny worms per day.

When untreated, those microfilarial worms invade the skin and travel throughout the body. That results in extreme, extensive, and persistent itching, along with subcutaneous bumps and eventual blindness after they burrow into the eyes.

The parasite has infected up to 25 million people (almost all in Africa), and suicide due to the debilitating itch is unfortunately not uncommon.

There are many reports of people in Africa who never get relief despite deep and intense scratching. In the worst cases, individuals have resorted to heating machetes over a fire and using the hot blades to “numb” or skin their backs out of desperation. Some have used broken shards of ceramic pots to try to gouge the worms out to no avail, and others have dumped boiling hot water on themselves in an attempt to feel “better” — anything to make the itching stop.

Two of this year’s Nobel Prize winners in Medicine, Drs. Omura (Japan) and Campbell (USA) were recognized for their discovery of a drug used to treat River Blindness. More:

Source: +Johnathan Chung responds to a question in the Science on Google+ community. The best comments or answers to questions will be posted as part of our  #Askascientist  series. Do you have science questions for us? Use the Science Outreach category to ask the science community.


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  1. Here’s more info on onchocerciasis (“river blindness”) from the WHO and CDC for anyone interested in further reading:

    It’s on the list of neglected infectious diseases:

    Merck & Co., Inc. is the pharmaceutical company that makes ivermectin, and they’ve provided the drug free of charge since 1987 to any government or NGO that demonstrates the need and capability to distribute it:

    That amounts to hundreds of millions of doses of the drug per year (people need to take the drug once or twice a year for 10-15 years).


  2. Johnathan Chung I was intrigued to find out that ivermectin opens glutamate gated chloride channels found in invertebrates like worms and parasites (my research is on membrane transporters). Fortunately, mammals don’t have this type of channel, so the drug does not target us. More Cl- entering parasite cells means that they are hyperpolarized, paralyzing the muscles and essentially starving them to death. The structure of the glutamate gated chloride channel with ivermectin bound has been solved:


  3. Linda Strickland Kimball Yes, I agree. Overall, I think the amount of good done is more than the hassles, frustrations, and outrage we frequently focus on through mainstream news.

    People, organizations, companies, and systems are very complex, and the tendency to think about them (and ourselves) as being all good or all bad — depending on our motives and outlook — is called “splitting” in psychology:


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