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The East African : Mar 30th 2015
38 The EastAfrican OUTLOOK MARCH 28 - APRIL 3, 2015 S CI E N C E Using parasites to fight cattle disease Animals a≥e less likely to die f≥om East Coast feve≥ when co-infected with a lesse≥ pa≥asite By CHRISTABEL LIGAMI Special Correspondent R esearch into the cattle killer disease East Coast fever has found a protective process that may also work in human malaria infections. The study, published in Science Advances, suggests that seeking a simple vaccine that could protect cows from East Coast fever by inoculating them with a related but far less harmful parasite may protect them against severe disease. A similar process may work in malaria, where infection with the less harmful Plasmodium vivax parasite may protect humans from the Plasmodium falciparum parasite. The parasites cause malaria, which kills more than 600,000 people around the world each year. African cattle infected with the lethal parasite that kills one million cows per year are less likely to die when co-infected with the parasite’s milder cousin, according to the study. The findings suggest that “fight- ing fire with fire” is a strategy that could work against a range of parasitic diseases. The immediate implications are for the battle in Africa against a tick-borne cattle parasite, Theileria parva, which causes East Coast fever. The disease kills one cow every 30 seconds and causes $300 million in livestock losses each year, mostly for poor herders. The worst hit countries in Af- rica are Kenya, Uganda, Rwanda, Tanzania and Burundi, DR Congo, Malawi, Mozambique, South Sudan, Zambia and Zimbabwe. The study, “Co-infections determine patterns of mortality in a pop- BRIEFS Scientists unveil Ebola-proof gadget A tablet that can withstand being doused in chlorine has been developed to keep medics caring for patients with Ebola safe. Designed by technology volunteers and Google, the device can be used while wearing gloves, in storms and in high humidity. Medecins Sans Frontieres put out a call for an Ebola-proof tablet to help teams record vital patient information. At the height of the current outbreak, doctors were shouting patient notes across fences to avoid contamination. Smart bandage to help detect bedsores early Herdsmen from Isiolo County in eastern Kenya study the carcass of a cow that died of East Coast Fever. Pic: File FINDINGS COULD AID WAR AGAINST MALARIA The protective effect against East Coast fever that appears to be provided by the milder parasites could be relevant to the fight against malaria. Like East Coast fever, malaria is caused by a single-celled parasite, Plasmodium, although more than one species of Plasmodium can cause malaria. The deadliest species is Plasmodium falciparum, whereas Plasmodiu m vivax is more widespread but causes less severe disease. “A protective effect of Plasmodium ulation exposed to parasite infections,” was conducted as part of an Infectious Diseases of East African Livestock (IDEAL) project, a multipartner study that includes the Nairobi-based International Livestock Research Institute (ILRI). The project followed more than 500 indigenous East African shorthorn zebu calves in Western Kenya during their first year of life. The calves were routinely exposed to both the T parva parasite vivax could explain why bednets used in places where both parasites are common are less effective in reducing malaria deaths than when used in places where Plasmodium falciparum is dominant,” said lead author of the study on East Coast fever Mark Woolhouse, who is with the University of Edinburgh in the UK. He added: “A better understanding of how this milder parasite may protect against the more lethal form of the disease could generate new approaches to reducing severe illness and deaths from malaria.” and its less aggressive relatives such as Theileria mutans. The researchers discovered that co-infection with a lesser parasite was associated with an impressive 89 per cent reduction in deaths from East Coast fever. “This is an important finding; East Coast fever is a major burden for millions of poor people in Africa whose existence depends on healthy cattle,” said Phil Toye, a researcher at ILRI, which is leading an inter- national effort to develop a new vaccine against the disease. “The available control methods are very expensive for most farmers and herders, and if we could provide a cheaper approach, it could greatly reduce poverty in the region.” The current first-generation vac- cine being used by farmers is credited with saving 620,000 cows and a formulation released in 2012 has been in high demand. However, the vaccine costs $8 to $12 per animal, which is steep for many pastoralists and smallholder farmers. Also limiting its wider adoption are its strict refrigeration requirements and its production difficulties, as it takes 18 months to make a single batch of the vaccine. The ILRI researchers are now developing an East Coast fever jab that stimulates the production of antibodies to protect against an infection and also stimulates the cow’s immune system to use its own “natural killer T-cells” to attack white blood cells infected by the parasite. Phase one of the vaccine devel- opment will be carried out in Kenya, Malawi, Belgium, UK and US. Fa≥me≥s in Uganda to get disease-tole≥ant cassava By ISAAC KHISA The EastAfrican RESEARCHERS IN Uganda plan to release two new cassava varieties that are tolerant to the brown streak virus. Titus Alicai, principal researcher on cassava at the National Agricultural Crop Resources Institute - Namulonge, in central Uganda, told The EastAfrican that the two conventionally bred cassava varieties are the result of nearly 10 years of research. “We have applied to the National Plant Vari- ety Committee for the release of the cassava varieties, and we hope that any time starting June, farmers will have access to the new materials,” said Dr Alicai. Dr Alicai said there is a need to develop va- rieties that are resistant to the cassava brown streak virus disease in order to guarantee farmers high crop production. A cassava affected by the brown streak virus disease is normally brown and harder than a healthy tuber, which makes it inedible. Brown streak is most prevalent in the central and eastern regions of Uganda, where there is resistance to cassava mosaic virus. Improved varieties were released to farm- ers to avoid the mosaic disease, which ravaged parts of Uganda in the 1990s, causing starvation in some communities. So far 19 lines resistant to cassava mosaic have been developed, from just three in 1997. Subsequently, the incidences of cassava mosaic disease in the country have declined from 67 per cent in the 1990s to 17 per cent last year. Scientists “Cassavas resistant to the brown streak virus disease will guarantee farmers high yields.” Titus Alicai, researcher, National Agricultural Crop Resources Institute, Uganda say the dis- ease, which affects the tuber, was first detected in Tanzania in 1936 and later Uganda, Kenya, Rwanda, Burundi, and the Democratic Republic of Congo, is spread through propagation, and by a whitefly vector (bemisia tabaci), which is predominant in the affected countries. According to the Food and Agricultural Or- ganisation of the United Nations, about 70 million people depend on cassava for their livelihood in the developing world. In addition to being drought-tolerant, the crop is relatively cheap to produce because it does not require expensive inputs such as fertilisers or improved seeds as farmers often replant cuttings from the previous crop. Whereas cassava farming ensures food se- curity in Uganda with the current per capita consumption standing at 120 kilogrammes, its production remains low at an average of 13 tonnes per hectare compared with 20 tonnes in India and some parts of Asia due to poor crop husbandry as well as pests and diseases. A study seeks to test the efficacy of prostate cancer drugs. Pic: File Improved cures for hookworm expected Better treatments for hookworm are on the horizon after the genome Ancylostoma ceylanicum, the less common of the two hookworm species that affect humans, was sequenced in the US. The genome data offers more targets for drug and vaccine research. The research, published in Nature Genetics found an extensive set of genes that control the hookworm’s ability to survive by suppressing the host’s immune system. Hookworm is a leading cause of iron-deficiency, which can cause disability and even death. Scientists have created a smart bandage they say can detect bedsores long before they become visible. Bedsores can develop when a patient is laid up in bed, and prolonged pressure hampers blood flow, damaging the skin. The sticking plaster uses electrical currents to detect early tissue damage as pressure ulcers start to form. Animal testing suggests a prototype works as a warning system. Human trials are now needed to test these findings, Nature Communications reports. Blood test could aid prostate cancer cures A blood test that measures the number of cells shed from prostate tumours into the bloodstream can act as an early warning sign that treatment is not working, a major new study shows. Researchers from The Institute of Cancer Research, London showed that measuring the number of circulating tumour cells in the blood predicted which men were benefiting least from a prostate cancer drug after as little as 12 weeks of treatment.
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