National leaders and the Medicine Nobel

Several Latin American countries have been declared free of sleeping sickness

October 25, 2015 06:38 pm | Updated 06:38 pm IST

Former U.S. President Jimmy Carter takes questions from the media

Former U.S. President Jimmy Carter takes questions from the media

What have national leaders like Ho Chi Min of Vietnam, Chairman Mao of China and Jimmy Carter of America to do with this year’s Nobel Prize in Physiology or Medicine? Reports have it that Ho Chi Min was greatly disturbed by the loss of thousands of soldiers (fighting the Americans in the Vietnam War) to malaria. He appealed to his ally, Chairman Mao, stating that a wild plant in rural Vietnam was claimed to cure malaria, and whether he could direct Chinese scientists to help isolate any active anti-malarial drug molecules from such a plant. Mao did so, and decades of work by Chinese scientists led to the drug artemisinin. The main player behind this was a lady scientist called Tu You You, who was honoured with the Nobel Prize in Medicine a few weeks ago. (Apparently when the Nobel Committee tried to call Tu You You (what a lyrical name!), they could not; she was away in the hinterlands, presumably working away).

Former President of America, Mr. Jimmy Carter, after retirement, established the Jimmy and Rosalynn Carter Center in 1982 with the theme: “Waging Peace, Fighting Disease, Building Hope”. In the area of fighting disease, the Center collaborated with Emory University at Atlanta, GA, and the drug firm Merck. Together, they focused on the disease called Human African Trypanosomosis (also spelt as trypanosomiasis), which affects vision, leads to sleeping sickness, lymphatic swelling and elephantiasis, and overall lethargy. This disease was found to spread across 10 million square km in Sub-Saharan Africa (Sudan, Ethiopia, Uganda, Mali, Nigeria, Kenya, Gambia, Zimbabwe etc, particularly along river coasts (hence the name river blindness). It affects not only people but also livestock, where it leads to drop in milk and meat production, abortions and gradual weakness and wasting away. The Carter Center, in collaboration with Lions International, Merck Institute and in-house support, launched a programme to fight and end trypanosomosis in affected areas.

The end results have been stunning and successful. The researchers, led by Dr William C Campbell of the Merck Center, obtained a natural product called Avermectin (sent to them by Dr. Satoshi Omura of Tokyo, Japan, who showed its effectiveness against parasitic infections), tweaked its chemical structure a bit to produce the drug called Ivermectin (Merck’s trade name for this is Mectizan). This drug cures this debilitating disease and also protects against latter day recurrence. One tablet a year (yes, just one per year) for 10 years is the dose; rather similar to how we administer vaccines! To date, thanks to the Carter Center’s request and participation, Merck has given away 270 million tablets of Ivermectin across not just Africa but also in parts of Latin America (Mexico, Guatemala, Ecuador, Venezuela, Colombia, Brazil) and in the Arab country Yemen. Several of these Latin American countries have been declared trypanosomosis-free.

Why and how does trypanosomosis come about and how does it affect the body of the infected animals and humans? It is caused by a parasitic protozoan (a type of roundworm) that resides inside the fly called Tsetse (or Tzetze, also called tik tik; lyrical names again), which abound along river coasts across Sub-Saharan Africa and parts of Latin America. When the tsetse fly bites you, it delivers the villain parasite. This is what leads to the sleeping sickness, elephantiasis, lymphatic swelling and inflammation of the cornea of the eye, leading to loss of vision (river blindness or ‘onchocerciasis’ as the eye doctors call it).

How was the solution found? It was in the 1970s that Dr. Satoshi Omura, working at the Kitasato University in Tokyo, identified some microbes called S treptomyces in the soil, and one form of it called S . avermitilis , which produces molecules that fight roundworms and other parasites. He isolated one of them, which he called avermectin and sent it to Merck in the US. William Campbell worked on it, modified it into a more effective molecule which he named Ivermectin (apparently named after a village in UK called Iver; Campbell is of Irish origin), and history was made. Campbell and Omura share half the prize amount, while Tu You You gets the other half. Incidentally, Jimmy Carter himself received the Nobel Peace Prize in 2002, for his humanitarian efforts.

Does trypanosomosis through such a parasite occur in India? To date, thankfully enough, no; and even if it does, ivermectin will help take care of it. Thus, the sleeping sickness we see often in government offices has other origins.

dbala@lvpei.org

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