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The East African : Oct 10th 2015
30 The EastAfrican OUTLOOK OCTOBER 10-16,2015 S CI E N C E Trio wins Nobel for parasite medicine The committee said thei≥ wo≥k has helped combat the debilitating diseases A JOINT REPORT The Washington Post was testing a new medicine to fight parasites in domestic and farm animals. The Irish-born scientist realised that a parasitic worm in horses bore an amazing resemblance to the parasite that causes river blindness in humans. It was a simple connection, al- W most too good to be true, so he allowed himself only a moment’s excitement. “We’d see other (drugs) rise and fall,” Campbell, now 85, said in an interview on September 5. “The probabilities are overwhelming that the whole thing is going to fall apart. Most drug candidates don’t ever reach the marketplace.” In the end, a form of the drug that Campbell and others developed succeeded where previous treatments had failed. Their work resulted in a sharp decline in river blindness, a parasitic infection that has blinded tens of millions of people in Africa, Latin America and other povertystricken countries. It also helped reduce the incidence of filariasis, another parasitic disease that can result in elephantiasis, a painful and disfiguring swelling in the legs and lower body. Last week on Monday, Campbell and a fellow scientist who helped develop the treatment, Satoshi Omura of Japan, were awarded the Nobel Prize in medicine. Chinese researcher Youyou Tu, who discovered a drug known as artemisinin that significantly cut death rates from malaria, shared in the prize. The scientists also will share an award of nearly $1 million. “These two discoveries have pro- vided humankind with powerful new means to combat these debili- illiam Campbell’s eureka moment came in 1975, as he Revolutionary treatment for parasitic diseases ��������������������������������������������������������������������������������������������������������������������������������������� Carriers: ��������������� Avermectin / Ivermectin active agent discoverer found in soil-dwelling bacteria river blindness, elephantiasis* treats the herb Artemisia annua malaria �������������������������������������������������������������� Elephantiasis 1 Insect(mosquito /blackfly) injects parasite larvae into the body 2 4 Malaria mature and produce thousands of new larvae (microfilarie) Another insect takes blood and ingests the parasite 3 River blindness Parasitic worms Elephantiasis ������������������� lymphatic vessels Malaria Plasmodium falciparum liver, blood cells �� Artemisinin mosquito organ in which the parasite matures blackfly name of parasite Uganda to int≥oduce ≥ubella vaccine By EVELYN LIRRI Special Correspondent A RUBELLA vaccine will be introduced to Uganda’s routine immunisation programme by 2017, the Ministry of Health has said. Uganda has applied to the Glo- The larvae invade the blood/tissues River blindness Onchocerca volvulus subcutaneous tissues bal Alliance for Vaccine Initiative (GAVI) to have the vaccine available in the country in the next two years, according to Henry Luzze, acting programme manager for the Uganda National Expanded Programme on Immunisation (Unepi). GAVI funds most childhood im- munisation programmes in subSaharan Africa. Rubella is a contagious viral Source: Nobelprize.org, WHO, CDC tating diseases that affect hundreds of millions of people annually,” the Nobel committee said in a statement. “The consequences in terms of improved human health and reduced suffering are immeasurable.” Some 3.4 billion people in 100 nations are at risk of the diseases. Committee member Hans Forssberg said the trio’s work “has promoted wellbeing and prosperity for both individuals and society.” Tu, 84, inspired by a description in a 1,700-year-old Chinese text of the use of sweet wormwood to combat fever, discovered artemisinin, which has been used by millions against malaria. She is affiliated with the China Academy of Traditional Chinese Medicine in Beijing. Omura, 80, of Kitasato Univer- The trio’s work “has promoted well-being and prosperity for both individuals and society.” Hans Forssberg, committee member *also called lymphatic filariasis sity in Tokyo, collected thousands of soil samples to isolate those that contained promising antibacterial agents. Campbell, an expert in parasite biology who spent decades working for pharmaceutical giant Merck, picked up on Omura’s work and developed a compound known as avermectin, which proved incredibly effective at killing off parasites in some animals. A modified form of that com- pound, known as ivermectin, showed similar results in humans. If taken annually, the drug relieves the agonising itching that often accompanies river blindness and effectively halts the progression of the debilitating disease. In 1987, Merck pledged to provide the drug to anyone who needed it, free of charge, for as long as necessary. It established a donation programme that works in partnership with the World Health Organisation, health ministries and non-government health groups. Hundreds of millions of doses are distributed each year, many of them in remote parts of Africa. Campbell, who spent many years as an associate fellow at Drew University in New Jersey after retiring from Merck, said the Nobel news came as “a tremendous shock.” He said he felt honoured to represent a much larger group of researchers, including Omura, whose work led to the breakthrough. But he also insisted that his biggest reward came decades ago. He recalled a visit to the small West African country of Togo to observe clinical trials of the drug he helped develop. There, he saw young boys whose lives would turn out very differently partly because of his work. “To see a blind man surrounded by little kids who are not going to be exposed to that risk, in a village where half the adult males were blind... That’s obviously a very moving experience,” Campbell said. By Brady Dennis, Lenny Bernstein and Jeff Guo New mala≥ia d≥ug fo≥ p≥egnant women developed By CHRISTABEL LIGAMI Special Correspondent SCIENTISTS HAVE come up with a new drug that could be more effective in preventing malaria in pregnant women, especially where there is resistance to current treatments. Researchers from Liverpool School of Tropical Medicine, the Centres for Disease Control and Prevention in Kenya and the US; and from the Kenya Medical Research Institute, have found that dihydroartemisinin-piperaquine (DHP), may be more effective in preventing malaria in pregnant women. The World Health Organisation currently rec- ommends that women in areas of stable malaria transmission receive intermittent preventative treatment in pregnancy (IPTp) with the antimalarial drug sulfadoxine-pyrimethamine (SP). WHO recommends that SP be given at each scheduled antenatal clinic visit except in the first trimester. However, scientists say high levels of resistance from the malaria parasite to this drug threatens its efficacy. “Like all malarial treatments, the plasmodium parasites have quickly developed resistance to this drug, meaning that in many areas, SP-IPTp is rapidly becoming ineffective and an alternative approach will soon be needed,” say the researchers. In their study, the scientists found that de- ployment of DHP for malaria in the second and third trimesters of pregnancy is associated with a significant decrease in adverse maternal and infant outcomes. The study evaluated the efficacy and safety of two alternative strategies in comparison with standard treatment recommended for the prevention of malaria in 1,546 HIV-negative preg- nant women in western Kenya. The study looked at two alternatives to the recommended treatment strategy — intermittent screening with malaria rapid diagnostic tests (RDTs) and treatment of RDT-positive women with the new drug dihydroartemisininpiperaquine (ISTp-DP); and intermittent preventative treatment with dihydroartemisininpiperaquine (IPTp-DP). It was found that there were more instances of malaria with ISTp-DP compared with the existing IPTp-SP strategy, however there was a much lower instance of malaria in the IPTp-DP treated group. “Malaria in pregnant women is a serious pub- lic health problem, and in areas of high resistance to SP it is clear that an alternative treatment is needed,” said Feiko ter Kuile, the study leader and a professor at Liverpool School of Tropical Medicine. A pregnant mother infected with the rubella virus is more likely to pass it on to her unborn child. Picture: File infection, which is transmitted when an infected person sneezes or coughs. There is no known treatment for rubella and the disease can only be prevented through immunisation. Although it causes mild illness in children, it can have serious consequences in pregnant women, causing foetal death or defects known as congenital rubella syndrome (CRS). A pregnant mother who is in- fected with the rubella virus has a 90 per cent chance of transmitting it to her unborn child, causing defects such as deafness, blindness and heart problems. According to the World Health Organisation, more than 100,000 babies are born with congenital rubella syndrome every year, mostly in developing countries in Africa and Southeast Asia, where vaccination levels are low. Andrew Bakainaga, Uganda WHO country advisor, said the vaccine will be administered alongside that for measles during routine immunisation campaigns. “Some of the reported measles outbreaks have turned out to be rubella, which shows that we have a big rubella problem,” said Dr Bakainaga. Rwanda and Tanzania have already introduced the rubella vaccine in their routine immunisation programmes.
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