Thursday 10 March 2016

Guinea worm gone

I got a real good education in Graduate School in Boston. It was partly the formal courses which I sat on "subjects" that we didn't know existed in TCD back in Dublin: a whole semester on 'evolution' with Lynn Margulis, ditto 'mammalogy', ditto 'physiological ecology', ditto 'multivariate statistics'. But I also learned a lot from my fellow students: eating ice-cream & loading a salad bowl, for example. My boss, a man of wide interests, recommended that I read his old Parasitology text-book, which was on the shelves down in the basement where I was living. He was an aficianado of Dracunculus medinensis the Guinea worm.  You can hardly admit to loving this parasitic invader, but you can nevertheless be fascinated by its life cycle and the peculiar methods used to rid patients of the adult worms.  Dracunculus lives part of its life in tiny copepod crustaceans which swim about in tropical fresh water. When they are consumed my mammals, including people, who drink the water, the copepods get dissolved by the stomach acid and the Dracunculus larvae burrow through the wall of the intestine and develop into adults among the wobbly bits over the next 3-4 months. When a female worm meets a male, they love each other very much, the male sinks back exhausted and dies from his exertions, the female begins a slow shoving journey through liver and lights, muscle and fat, until she comes to rest just beneath the skin. Somehow this creature, knows where the legs are and tends to come to rest in the lower legs. But occasionally she gets blind-sided by other low hanging appendages and heads for the hand or <eeeuuuw> the scrotum. Her journey is exquisitely painful to the unwilling host.

Evolution has shaped the female Guinea-worm's behaviour to facilitate the continuation of her life cycle. If the skin above the lurking female gets wet, then she burrows rapidly to the surface and sheds thousands of eggs into the water in the hope that some of them will encounter a copepod. This sensitivity to water can be used to start a cure: wrap the leg in a wet towel then when the end of the worm breaks the skin surface you can seize it and e v e r  s o  s l o w l y draw the whole worm out. As she can grew to 80cm in length, this pulling can take several days.  You wrap your winnings round a twig or pencil to stop the whole thing slithering back into the flesh.  If you pull too hard then the bloody worm breaks and you have a serious case of septicaemia on your blistered legs. I'm sure that there were experts at these delicate extractions in many sub-Saharan villages.

I use the past tense advisedly, because at more or less the same time I was reading about Guinea-worms in Boston, retiring President Jimmy Carter was thinking about what he was going to do for the rest of his life. His existential solution was to endow the Carter Centre on some derelict urban blight in Atlanta, Georgia. This institution was established with the brief "to advance human rights and alleviate human suffering".  Grand for a mission statement but What to do next in detail?
  • First build a complex of offices and auditoria, a library and museum, all set in lovely parkland, 
  • Then appoint a Board of Trustees packed with the great and the good and capable of networking their way to solutions.
  • Have the Board appoint Effectives to do committee work and decide how the substantial, but not infinite, endowment can be most effectively leveraged.
  • Launch some specific projects: preferably those that will yield tangible results within the life time of the soon to be ex-President.
  • It's also important to have projects that can be written up in a headline + 600 words by the Washington Post.
And it was so. Tuberculosis, Malaria, HIV/AIDS were left to other groups [Gates Foundation for example] with far deeper pockets. Along with election watching, the abolition of the death penalty and conflict resolution, the Carter Centre decided that they would take on the dreaded Guinea-worm which at the time in the mid 1980s infected 3.5 million people, mainly in sub-Saharan Africa. The map shows countries in which the worm was endemic in 1985, the hatched countries are those that still had worms 20 years later.  Now I read in Nature 10th Feb 2016, that Dracunculus has almost gone the way of all smallpox.  A combination of Carter Centre monogrammed winding-pencil distribution [kidding!]; water filters, education and political barracking has reduced the disease Dracunuliasis to a mere 22 cases in four countries for calendar year 2015: an astonishingly effective 100,000-fold reduction.  At one point, President Carter bluffed his opposite number in Ghana that with his clout he could persuade science to start calling Dracunculus the Ghana-worm.  “There isn’t a Guinea worm left in Ghana now, Carter told journalists with a grin . . . "  The remaining four benighted nations - Chad, Ethiopia, Mali, and South Sudan - are beset with civil wars that not even Carter's mediators can stop.  Civil war rides with pestilence and makes it really difficult for health-care workers to get where they are needed.

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