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Great News for Cattle, Sheep and Goats
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| 3. Great News for Cattle, Sheep and Goats By Nhlanhla Nyide If anyone was ever in doubt about the dynamic contribution that science, technology and medical research can make to solving South Africa's problems, they need look no further than the University of Pretoria's Department of Veterinary Tropical Diseases, located at Onderstepoort north of Pretoria. Here, a team of scientists from the University and the Onderstepoort Veterinary Institute, under the leadership of Professor Basil Allsopp, has sequenced and annotated the complete genome of the bacterium Ehrilchia ruminatium, the causative agent of the deadly Heartwater Disease which often decimates cattle, sheep and goat herds throughout sub - Saharan Africa. In simple terms, the villain of the piece has now been fully revealed, and it's only a matter of time before this parasite is brought under control and forced to abandon its murderous spree which has killed millions of animals and has often spelled ruin for generations of Africa.s farmers. Here is hard evidence that Africa.s problems can be solved with African resources. Commenting on this development, Professor E.P. Rybicki of the Department of Molecular and Cell Biology at the University of Cape Town said: "No-one else working from Africa is probably even close to sequencing any cellular organism, let alone one that is involved in causation of a globally important disease of livestock. This achievement ranks alongside those of the Brazilian Genome Consortium, which in turn are of world-class. When one realises that the total cost of this achievement is less than R5 million, which is less than US$1 million, one realises that this team has done one of the most cost effective full cellular genome sequences yet. And they did it as a part of a larger project aimed at providing a vaccine to heartwater - and they have almost reached that goal, too. The team deserves the highest praise..." The project was selected as a lead programme by the Department of Science and Technology and was largely funded by grants from the Department, together with a generous contribution from the government of the Netherlands, via Utrecht University. Ehrlichia ruminantium is carried by the bont tick, and is prevalent in the warmer and wetter parts of the country. Sir Arnold Theiler started work on heartwater when the Onderstepoort Veterinary Institute was founded in 1908, but it was not until 1925 that Edmund Cowdrey, also working at the Institute, identified the causative bacterium. In the 1950s this led to the development, at Onderstepoort, of a blood vaccine which is still in use today. It is only partially effective, has to be kept in cold storage conditions at all times, is expensive to produce and costly to use. Nonetheless, it is the only commercially available vaccine at this time. The present breakthrough is a direct result of the astonishing progress in biology in the past half century, notably the improvements in sequencing of DNA, deriving from the human genome project. That undertaking, which culminated in the final complete reading of the human genome sequence, consisting of three billion base pairs, was the largest biological project ever undertaken, involved thousands of scientists from sixteen institutions in Europe, the USA and Japan, and cost an estimated US$3 billion. |
 Prof Basil Allsopp (right) and Prof Albert Cornelissen, Dean of the Faculty of Veterinary Medicine, Utrecht University (left). |
| It is worth noting that, of the 203 bacterial genomes sequenced,
only a handful are intracellular bacteria like Ehrlichia ruminantium.
This is because of the serious technical problems which must be
overcome to obtain pure intracellular bacterial DNA, uncontaminated by
DNA from the much larger host cell nucleus. An intracellular organism
is a parasite that lives inside the cell and thereby "hides" from the
host's immune system, in much the same way that the AIDS virus and the
malaria parasite operate in the human body. Having completed the sequencing, the hunt for an effective vaccine can now go forward, much as a detective would hunt for clues at the scene of a crime. Professor Basil Allsopp explains: "We now have a new three-year grant from the National Research Foundation, and we're very pleased with that. My feeling is that we could have a commercially viable vaccine in about five years if we had sufficient resources and people." A successful outcome to this research can't come too soon for many livestock farmers spread across the continent, since there are substantial financial implications hinging on the research. In KwaZuluNatal, for example, it is estimated that up to 30% of all goats belonging to small-scale livestock owners may contract heartwater each year. Although hard statistics are not available, it is possible that a third of these may die, so it is easy to imagine what a boon an effective vaccine would be in that area. And large scale livestock farmers are equally at risk. It is estimated that about 150 million domestic ruminants - that's cattle, sheep and goats - are at risk from this disease throughout Africa, and a vaccine could change the whole face of Africa's ruminant agriculture overnight. This is particularly important when one considers the fact that global warming scenarios strongly suggest that in future, southern Africa is likely to be drier than it is now. At present, about half our country's agricultural production is animal-based, and half of it is crop-based. The crop-based segment accounts for about 70% of water usage, and the animal segment, around 4%. When you consider the water-resource problem, both presently and in the future, the clear implication is that crop production is close to its limit, and therefore South Africa's future agricultural endeavours will increasingly have to rely on animal-based farming. Whatever happens, the scientists on Professor Allsopp's team are pressing forward, inspired by the possibility that their work may help turn Africa's rural areas into highly productive and profitable ruminant farming centres. More information on the Heartwater genome project and Heartwater disease is available at: http://www.bi.up.ac.za/Ehrlichia_ruminantium. |
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Nominations of potential candidates for the Technology Innovation Agency (TIA) Board of Directors
