New advances in the battle against a major disease threat to cattle and people in Africa

ILRI research on biotechnology to fight a major disease threat to cattle and people in Africa

An 8-month old cloned Boran calf named Tumaini (meaning ‘hope’ in Kiswahili), on the left, is part of a long-term ILRI research project to develop cattle for Africa that are genetically resistant to trypanosomiasis (photo credit: ILRI/Paul Karaimu).

The International Livestock Research Institute (ILRI), a member of the CGIAR Consortium, is a non-profit organization based in Africa. ILRI’s mission is to use the best and safest livestock science available to confront poverty, hunger, and disease in the developing world, where livestock provide livelihoods and food for hundreds of millions of people.

One of ILRI’s most important priorities today is to help poor livestock keepers in Africa deal with the constant threat of a devastating disease called trypanosomiasis. This disease is arguably Africa’s most important livestock disease, wasting and killing cattle, commonly the most important asset of poor households. The human form of the disease is called sleeping sickness, which afflicts tens of thousands of people every year, killing many of them, and putting tens of millions more people at risk.

As part of ILRI’s comprehensive fight against trypanosomiasis, the institute is now in the very early stages of a project to develop disease-resistant cattle, which could save the lives of livestock and people both. Thus far, ILRI and its partners have taken a preliminary step in the process, which involved successfully cloning a male calf from one of East Africa’s most important cattle breeds, the Boran. The calf is healthy and is being raised at ILRI’s research facilities in Kenya.

A next step is to develop a new Boran clone modified with a gene that naturally confers resistance to the disease. This involves using a synthetic copy of a gene sequence originally identified in baboons that should protect cattle against this devastating disease.

A final step will be to use these disease-resistant cattle in breeding schemes that will provide African countries with another option in their fight against trypanosomiasis.

This research potentially offers a reliable, self-sustaining and cost-effective way of protecting tens of millions of African cattle against disease and untimely death, as well as dramatically reducing poverty across Africa. By reducing the reservoir of pathogens, this should also help to save thousands of human lives each year.

It could take up to two decades to develop disease-resistant cattle herds for Africa. ILRI and its partners are also continuing to pursue other options for fighting trypanosomiasis, such as rationale drug treatment and integrated disease control methods.

For ILRI, public safety and animal welfare are paramount; this means working with all the relevant Kenyan and international regulatory authorities to ensure that the highest bio-safety standards are always employed. In line with its commitment to transparency, ILRI places all of its research results in the public domain.

ILRI is working with a team that includes scientists from New York University, along with experts from the Roslin Institute in Scotland, and Michigan State University in the USA. The fundamental research aspects of this project are being funded by the US National Science Foundation.

For further information, see:
ILRI website:
http://www.ilri.org/breadtrypanosome

National Science Foundation:
www.nsf.gov/news/news_summ.jsp?cntn_id=116932

2009 paper published in the Proceedings of the National Academy of Sciences (USA) on original breakthrough in this research project:
http://dx.doi.org/10.1073%2Fpnas.0905669106

Or contact one of the following people:

Jimmy Smith
ILRI Director General
j.smith@cgiar.org

Suzanne Bertrand
ILRI Deputy Director General for Biosciences
s.bertrand@cgiar.org

Steve Kemp
Leader of ILRI’s research on this topic
s.kemp@cgiar.org

About ILRI: better lives through livestock
www.ilri.org
The International Livestock Research Institute (ILRI) works with partners worldwide to enhance the roles that livestock play in food security and poverty alleviation, principally in Africa and Asia. The outcomes of these research partnerships help people in developing countries keep their farm animals alive and productive, increase and sustain their livestock and farm productivity, find profitable markets for their animal products, and reduce the risk of livestock-related diseases. ILRI is a not-for-profit institution with a staff of about 600 and, in 2012, an operating budget of about USD 60 million. A member of the CGIAR Consortium working for a food-secure future, ILRI has its headquarters in Nairobi, Kenya, a principal campus in Addis Ababa, Ethiopia, and offices in other countries in East, West and Southern Africa and in South, Southeast and East Asia.

About CGIAR: working for a food-secure future
www.cgiar.org
CGIAR is a global partnership that unites organizations engaged in research for a food-secure future. It is carried out by 15 centres that are members of the CGIAR Consortium and conducted in close collaboration with hundreds of partner organizations, including national and regional research institutes, civil society organizations, academia and the private sector. The CGIAR’s 8,000 scientists and staff work in the developing world to reduce rural poverty, increase food security, improve human health and nutrition, and ensure more sustainable management of natural resources. With unparalleled research infrastructure and dynamic networks across the globe, and maintaining the world’s most comprehensive collections of genetic resources, CGIAR is the only institution with a clear mandate on science and technology development for the eradication of hunger and poverty at the global level.

Animal-to-human diseases: From panic to planning–new recommendations for policymakers

Greatest Burden of Zoonoses Falls on One Billion Poor Livestock Keepers

Map by ILRI, published in an ILRI report to the UK Department for International Development (DFID): Mapping of Poverty and Likely Zoonoses Hotspots, 2012.

The UK’s Institute for Development Studies (IDS) has published a 4-page Rapid Response Briefing titled ’Zoonoses: From panic to planning’.

Veterinary epidemiologist Delia Grace, who is based at the International Livestock Research Institute (ILRI), along with other members of a Dynamic Drivers of Disease in Africa Consortium, based at the STEPS Centre at IDS, c0-authored the document.

The briefing recommends that policymakers take a ‘One-Health’ approach to managing zoonotic diseases.

‘Over two thirds of all human infectious diseases have their origins in animals. The rate at which these zoonotic diseases have appeared in people has increased over the past 40 years, with at least 43 newly identified outbreaks since 2004. In 2012, outbreaks included Ebola in Uganda . . . , yellow fever in the Democratic Republic of Congo and Rift Valley fever (RVF) in Mauritania.

‘Zoonotic diseases have a huge impact – and a disproportionate one on the poorest people in the poorest countries. In low-income countries, 20% of human sickness and death is due to zoonoses. Poor people suffer further when development implications are not factored into disease planning and response strategies.

‘A new, integrated “One Health” approach to zoonoses that moves away from top-down disease-focused intervention is urgently needed. With this, we can put people first by factoring development implications into disease preparation and response strategies – and so move from panic to planning.

Read the Rapid Response Briefing: Zoonoses: From panic to planning, published Jan 2013 by the Dynamic Drivers of Disease in Africa Consortium and funded by the UK Department for International Development (DFID).

About the Dynamic Drivers of Disease in Africa
The Dynamic Drivers of Disease in Africa is a consortium of 30 researchers from 19 institutions in Africa, Europe and America. It conducts a major program to advance understanding of the connections between disease and environment in Africa. Its focus is animal-to-human disease transmission and its objective is to help move people out of poverty and promote social justice.

Over the past few decades, more than 60 per cent of emerging infectious diseases affecting humans have had their origin in wildlife or livestock. As well as presenting a threat of global disease outbreak, these zoonotic diseases are quietly devastating lives and livelihoods. At present, zoonoses are poorly understood and under-measured — and therefore under-prioritized in national and international health systems. There is great need for evidence and knowledge to inform effective, integrated One Health approaches to disease control. This Consortium is working to provide this evidence and knowledge.

Natural and social scientists in the Consortium are working to provide this evidence and knowledge for four zoonotic diseases, each affected in different ways by ecosystem changes and having different impacts on people’s health, wellbeing and livelihoods:

  • Henipavirus infection in Ghana
  • Rift Valley fever in Kenya
  • Lassa fever in Sierra Leone
  • Trypanosomiasis in Zambia and Zimbabwe

Of the 30 scientists working in the consortium, 4 are from ILRI: In addition to Delia Grace, these include Bernard Bett, a Kenyan veterinary epidemiologist with research interests in the transmission patterns of infectious diseases as well as the technical effectiveness of disease control measures; Steve Kemp, a British molecular geneticist particularly interested in the mechanisms of innate resistance to disease in livestock and mouse models, and Tom Randolph, an American agricultural economist whose research interests have included animal and human health issues and assessments of the impacts of disease control programs.

Delia Grace leads a program on Prevention and Control of Agriculture-associated Diseases, which is one of four components of a CGIAR Research Program on Agriculture for Nutrition and Health. Tom Randolph directs the CGIAR Research Program on Livestock and Fish. Steve Kemp is acting director of ILRI’s Biotechnology Theme.

 

 

Frontline livestock disease research in, and for, Africa highlighted in White House conversation today

Scientists at the International Livestock Research Institute (ILRI) are working with many partners to improve control of major diseases of cattle in Africa.

East Coast fever in African cattle, one of the target diseases of the International Livestock Research Institute (ILRI), is included in a message today at the White House delivered by Raj Shah, administrator of the United States Agency for International Development. Shah will remind his audience that East Coast fever kills one cow every 30 seconds in Africa. Watch the live stream and join the conversation at 11am ET at the White House today, when Shah and others will answer questions about Innovations for Global Development.

Two other target diseases of ILRI’s are contagious bovine pleuropneumonia and trypanosomosis. All three diseases affect millions of the world’s poorest farmers. And all remain underfunded because they occur mostly in developing regions of the world.

ILRI recently produced three short films on research battles against these diseases.

CBPP: A new vaccine project starts
Contagious bovine pleuropneumonia (known by its acronym, CBPP) is found throughout most of sub-Saharan Africa, where it causes most harm in pastoralist areas. The disease kills up to 15% of infected animals, reduces the meat and milk yields of infected cows (milk yields drop by up to 90%), and reduces the ability of infected oxen to pull ploughs and do other kinds of farm work. An existing ‘live’ vaccine against this disease produces severe side effects and gives only limited protection.

Watch this short (runtime: 2:35) ILRI film, ‘Developing a Vaccine for a Highly Contagious Cattle Disease’, on the research recently begun at ILRI and its partner institutes, including the Kenya Agricultural Research Institute, to develop a more effective vaccine against this form of acute cattle pneumonia. This research is funded by the German Federal Ministry for Economic Cooperation and Development (BMZ).

Trypanosomosis: A genetic approach to its control
Trypanosomosis, called sleeping sickness in humans, is a wasting disease that maims and eventually kills millions of cattle in Africa and costs farmers billions of dollars annually.

In 2011, using the latest gene mapping and genomic technologies, researchers at ILRI’s Nairobi, Kenya, animal health laboratories and at institutes in the UK and Ireland identified two genes that enable Africa’s ancient N’Dama cattle breed to resist development of the disease when infected with the causative, trypanosome, parasite.

This breakthrough should eventually make it easier for Africa’s livestock breeders to breed animals that will remain healthy and productive in areas infested by the parasite-carrying tsetse fly. The international team that came together in this project is an example of the disciplinary breadth and agility needed to do frontline biology today, and the complex research approaches and technologies now needed to unravel fundamental biological issues so as to benefit world’s poor.

ILRI’s collaborating institutes in this work include Liverpool University; the Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh; Trinity College, Dublin; and the University of Manchester. The Wellcome Trust funded the bulk of the work in this project.

Watch this short (runtime: 5:28) ILRI film, ‘Battling a Killer Cattle Disease’, on the international partnership that made this breakthrough in trypanosomosis research.

 

Trypanosomosis: A community-based approach to its control
Another ILRI research team has been working with partners and livestock keepers in West Africa to develop safer ways to treat their cattle with drugs to protect them from trypanosomosis. Parasite resistance to the trypanocidal drugs used to treat and prevent this disease has emerged in many areas and is a growing problem for farmers and governments alike. This collaborative research team recently developed good practices in the use of trypanocides to slow the emergence of drug resistance in the parasites that cause the disease. This film describes the disease and these practices, known as ‘rational drug use’, clearly and in detail to help veterinary workers and farmers treat animals safely.

ILRI’s partners in this project include the Centre International de Recherche-Développement sur l’Elevage en Zone Subhumid, Freie Universität Berlin, Laboratoire Vétérinaire Centrale du Mali, Centre Régional de la Recherche Agricole Sikasso, Project de Lutte contra la Mouche Tsétsé et la Trypanosomose (Mali), Pan-African Tsetse and Trypanosomiasis Eradication Campaign (Mali), University of Hannover, Direction Nationale de l’Elevage et l’Institut de Recherche Agronomique de Guinée, Tsetse and Trypanosomosis Control Unit (Ghana), Institut National de la Recherche Agronomique du Bénin and the Nigerian Institute of Trypanosomiasis Research. The project was funded by the German Federal Ministry for Economic Cooperation and Development (BMZ).

Watch this ILRI film, ‘Community-Based Integrated Control of Trypanosomosis in Cattle’ (runtime: 12.48), for clear instructions on how to deploy drugs to better control trypanosomosis over the long term.

Short film illustrates expanded, agile partnerships behind recent disease research breakthrough

This short (5-minute) film, ‘Battling a Killer Cattle Disease’, produced by the International Livestock Research Institute (ILRI), provides background and context for a recent research breakthrough made at ILRI’s animal health laboratories in Nairobi, Kenya, and at their partner institutions in the UK and Ireland. The research was funded over 7 years in large part by the Wellcome Trust in addition to the Consultative Group on International Agricultural Research (CGIAR).

Trypanosomosis is a wasting disease of livestock that maims and eventually kills millions of cattle in Africa and costs the continent billions of dollars annually.

In 2011, a group of geneticists at these collaborating institutions identified two genes that enable Africa’s ancient N’Dama cattle breed to resist development of the disease trypanosomosis when infected with the causative, trypanosome, parasite.

The team members were able to make use of the latest gene mapping and genomic technologies because they had the genetic systems and experimental populations of livestock in place to do so as these technologies came on stream.

Eventually, these results should make it easier for livestock breeders in Africa to breed animals that will remain healthy and productive in areas infested by the disease-carrying tsetse fly.

The international team that came together in this project is an example of the disciplinary breadth as well as agility needed to do frontline biology today. In this work, the team developed several new research approaches and technologies that were needed to unravel some fundamental biological issues, with likely benefits for many African farmers and herders.

Those interviewed in the film include Harry Noyes, at the University of Liverpool; Alan Archibald, at the Roslin Institute at the University of Edinburgh; Andy Brass, at the University of Manchester; and Steve Kemp and Morris Agaba, at ILRI.

Scientists identify livestock genes to unlock protection against one of Africa’s oldest animal plagues

Cow suffering from trypanosomosis

Cow suffering from trypanosomiasis (photo credit: ILRI/Elsworth).

An international research team using a new combination of approaches has found two genes that may prove of vital importance to the lives and livelihoods of millions of farmers in a tsetse fly-plagued swathe of Africa the size of the United States. The team’s results were published today in the Proceedings of the National Academy of Sciences (PNAS).

The research, aimed at finding the biological keys to protection from a single-celled trypanosome parasite that causes both African sleeping sickness in people and a wasting disease in cattle, brought together a range of high-tech tools and field observations to address a critical affliction of some of the world’s poorest people.

With increased surveillance and control, sleeping sickness infections in people have dropped ten-fold in the last 13 years, from an estimated 300,000 cases a year in 1998 to some 30,000 in 2009, with the disease eventually killing more than half of those infected. Although best known for causing human sleeping sickness, the trypanosome parasite’s most devastating blow to human welfare comes in an animal form, with sick, unproductive cattle costing mixed crop-livestock farmers and livestock herders huge losses and opportunities. The annual economic impact of ‘nagana,’ a common name in Africa for the form of the disease that affects cattle (officially known as African animal trypanosomiasis), has been estimated at US$4–5 billion.

In a vast tsetse belt across Africa, stretching from Senegal on the west coast to Tanzania on the east coast, and from Chad in the north to Zimbabwe in the south, the disease each year renders millions of cattle too weak to plow land or to haul loads, and too sickly to give milk or to breed, before finally killing off most of those infected. This means that in much of Africa, where tractors and commercial fertilizers are scarce and prohibitively expensive, cattle are largely unavailable for tilling and fertilizing croplands or for producing milk and meat for families. The tsetse fly and the disease it transmits are thus responsible for millions of farmers having to till their croplands by hand rather than by animal-drawn plow.

‘The two genes discovered in this research could provide a way for cattle breeders to identify the animals that are best at resisting disease when infected with trypanosome parasites, which are transmitted to animals and people by the bite of infected tsetse flies,’ said senior author Steve Kemp, a geneticist on joint appointment with the Nairobi-based International Livestock Research Institute (ILRI) and the University of Liverpool.

This genetics of disease resistance research was led by scientists from ILRI in Africa and from the UK universities of Liverpool, Manchester and Edinburgh, and involved researchers from other institutions in Britain, Ireland and South Korea.

The researchers drew on the fact that while the humped cattle breeds characteristic of much of Africa are susceptible to disease-causing trypanosome parasites, a humpless West African breed, called the N’Dama, is not seriously affected by the disease. Having been domesticated in Africa some 8,000 or more years ago, this most ancient of African breeds has had time to evolve resistance to the parasites. This makes the N’Dama a valued animal in Africa’s endemic regions. On the other hand, N’Dama cattle tend to be smaller, to produce less milk, and to be less docile than their bigger, humped cousins.

African agriculturalists of all kinds would like to see the N’Dama’s inherent disease resistance transferred to these other more productive breeds, but this is difficult without precise knowledge of the genes responsible for disease resistance in the N’Dama. Finding these genes has been the ‘Holy Grail’ of a group of international livestock geneticists for more than two decades, but the genetic and other biological pathways that control bovine disease resistance are complex and have proven difficult to determine.

The PNAS paper is thus a landmark piece of research in this field. The international and inter-institutional team that made this breakthrough did so by combining a range of genetic approaches, which until now have largely been used separately.

‘This may be the first example of scientists bringing together different ways of getting to the bottom of the genetics of a very complex trait,’ said Kemp. ‘Combined, the data were like a Venn diagram overlaying different sets of evidence. It was the overlap that interested us.’

They used these genetic approaches to distinguish differences between the ‘trypano-tolerant’ (humpless) N’Dama, which come from West Africa, and ‘trypano-susceptible’ (humped) Boran cattle, which come from Kenya, in East Africa. The scientists first identified the broad regions of their genomes controlling their different responses to infection with trypanosome parasites, but this was insufficient to identify the specific genes controlling resistance to the disease. So the scientists began adding layers of information obtained from other approaches. They sequenced genes from these regions to look for differences in those sequences between the two breeds.

The team at Edinburgh conducted gene expression analyses to investigate any differences in genetic activity in the tissues of the two cattle breeds after sets of animals of both breeds were experimentally infected with the parasites. Then, the ILRI group tested selected genes in the lab. Finally, they looked at the genetics of cattle populations from all over Africa.

Analyzing the vast datasets created in this research presented significant computational challenges. Andy Brass and his team in the School of Computer Science at the University of Manchester managed to capture, integrate and analyze the highly complex set of biological data by using workflow software called ‘Taverna,’ which was developed as part of a UK e-Science initiative by Manchester computer scientist Carole Goble and her ‘myGrid’ team.

‘The Taverna workflows we developed are capable of analyzing huge amounts of biological data quickly and accurately,’ said Brass. ‘Taverna’s infrastructure enabled us to develop the systematic analysis pipelines we required and to rapidly evolve the analysis as new data came into the project. We’re sharing these workflows so they can be re-used by other researchers looking at different disease models. This breakthrough demonstrates the real-life benefits of computer science and how a problem costing many lives can be tackled using pioneering E-Science systems.’

To bolster the findings, population geneticists from ILRI and the University of Dublin examined bovine genetic sequences for clues about the history of the different breeds. Their evidence confirmed that the two genes identified by the ILRI-Liverpool-Manchester groups were likely to have evolved in response to the presence of trypanosome parasites.

‘We believe the reason the N’Dama do not fall sick when infected with trypanosome parasites is that these animals, unlike others, have evolved ways to control the infection without mounting a runaway immune response that ends up damaging them,’ said lead author Harry Noyes, of the University of Liverpool. ‘Many human infections trigger similarly self-destructive immune responses, and our observations may point to ways of reducing such damage in people as well as livestock.’

This paper, said Kemp, in addition to advancing our understanding of the cascade of genes that allow Africa’s N’Dama cattle to fight animal trypanosomiasis, reaffirms the importance of maintaining as many of Africa’s indigenous animal breeds (as well as plant/crop varieties) as possible. The N’Dama’s disease resistance to trypanosome parasites is an example of a genetic trait that, while not yet fully understood, is clearly of vital importance to the continent’s future food security. But the continued existence of the N’Dama, like that of other native ‘niche’ African livestock breeds, remains under threat.

With this new knowledge of the genes controlling resistance to trypanosomiasis in the N’Dama, breeders could screen African cattle to identify animals with relatively high levels of disease resistance and furthermore incorporate the genetic markers for disease resistance with markers for other important traits, such as high productivity and drought tolerance, for improved breeding programs generally.

If further research confirms the significance of these genes in disease resistance, a conventional breeding program could develop a small breeding herd of disease-resistant cattle in 10–15 years, which could then be used over the next several decades to populate Africa’s different regions with animals most suited to those regions. Using genetic engineering techniques to achieve the same disease-resistant breeding herd, an approach still in its early days, could perhaps be done in four or five years, Kemp said. Once again, it would be several decades before such disease-resistant animals could be made available to most smallholder farmers and herders on the continent.

‘So it’s time we got started,’ said Kemp.

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See this news and related background material at ILRI’s online press room.

The International Livestock Research Institute (www.ilri.org) works with partners worldwide to help poor people keep their farm animals alive and productive, increase and sustain their livestock and farm productivity, and find profitable markets for their animal products. ILRI’s headquarters are in Nairobi, Kenya; we have a principal campus in Addis Ababa, Ethiopia, and 13 offices in other regions of Africa and Asia. ILRI is part of the Consultative Group on International Agricultural Research (www.cgiar.org), which works to reduce hunger, poverty, illness and environmental degradation in developing countries by generating and sharing relevant agricultural knowledge, technologies and policies. This research is focused on development, conducted by a Consortium (http://consortium.cgiar.org) of 15 CGIAR centres working with hundreds of partners worldwide, and supported by a multi-donor Fund (www.cgiarfund.org).

The University of Liverpool (www.liv.ac.uk) is a member of the Russell Group of leading research-intensive institutions in the UK. It attracts collaborative and contract research commissions from a wide range of national and international organizations valued at more than £110 million annually.

The University of Manchester (www.manchester.ac.uk), also a member of the Russell Group, is the largest single-site university in the UK. It has 22 academic schools and hundreds of specialist research groups undertaking pioneering multi-disciplinary teaching and research of worldwide significance. According to the results of the 2008 Research Assessment Exercise, the University of Manchester is now one of the country’s major research universities, rated third in the UK in terms of ‘research power’. The university has an annual income of £684 million and attracted £253 million in external research funding in 2007/08.

Scientists argue the importance of Africa’s diverse livestock — and the need for genebanks to conserve them

Steve Kemp, a geneticist at the Nairobi laboratories of the International Livestock Research Institute (ILRI) for both ILRI and the University of Liverpool, argues in this short video (2:24 minutes) the new opportunities — as well as urgent need — for exploring the remarkably rich livestock diversity that evolved and still exists on the highly diverse African continent.

‘We need to study the genetics of the animals,’ he says, as well as ‘the farming systems in which they are being used and their production characteristics. And that has never been done systematically in situ across this extraordinary diversity of African livestock.’ Kemp describes fast-improving technologies in the ‘new genetics’ — technologies that are allowing scientists, for the first time, to attempt these very broad kinds of genetic analyses. And he makes a case for establishing livestock genebanks to help preserve the continent’s livestock diversity, which is rapidly being lost. ‘Unless you move relatively quickly,’ warns Kemp, ‘there’ll be nothing left to study.’ Kemp makes these points in an article published in a June 2010 issue of the international journal Science. The co-authors of the article are Tadelle Dessie, an ILRI livestock breeding specialist based at ILRI’s campus in Addis Ababa, Ethiopia, and Olivier Hanotte, a geneticist that formerly worked at ILRI and now directs a Frozen Ark initiative at the University of Nottingham, in the UK. Although genebanks are an important ‘stop-gap’ for preserving livestock diversity, says Kemp, his article makes the point that ‘at the same time that you bank, you must understand the characteristics of what you’re preserving.' 'ILRI is well positioned to catalyze this kind of research,’ Kemp says. ‘It has strong links with Africa and with African partners, who have access to the livestock. It has the mix of skills it needs to understand the function of livestock, right across the spectrum from disease resistance to their role in the marketplace. And it also has the technology — the molecular tools and the informatics tools — to allow us to begin this process.’ ‘But ILRI cannot perform any of this analysis alone,’ warns Kemp. ‘It needs to network with partners in the West and across Africa.’

Science: 'Time to tap Africa's livestock genomes', 25 Jun 2010

BBC News: 'African livestock offers untapped genetic resource', 24 Jun 2010

Les experts avertissent que la disparition rapide du bétail indigène de l’Afrique menace l’approvisionnement alimentaire du continent

N'DamaHerd_WestAfrica

D’ « anciennes » espèces bovines d’Afrique de l’Ouest, résistantes aux maladies, figurent parmi les races qui risquent de disparaître parce que le bétail importé est en train de supplanter un précieux cheptel indigène.

Une action urgente est indispensable pour arrêter la perte rapide et alarmante de la diversité génétique du bétail africain qui apporte nourriture et revenus à 70 % des Africains ruraux et constitue un véritable trésor d’animaux résistants à la sécheresse et aux maladies. C’est ce que dit une analyse présentée aujourd’hui à une importante réunion de scientifiques africains et d’experts du développement.

Les experts de l’Institut international de recherche sur l’élevage (ILRI) ont expliqué aux chercheurs réunis pour la cinquième Semaine africaine des sciences agricoles (www.faraweek.org), accueillie par le Forum pour la recherche agricole en Afrique (FARA), que des investissements sont indispensables aujourd’hui même pour intensifier, en particulier en Afrique de l’Ouest, les efforts d’identification et de préservation des caractères uniques de la riche variété de bétail bovin, ovin, caprin, et porcin, qui s’est développée au long de plusieurs millénaires sur le continent et qui est aujourd’hui menacée. Ces experts expliquent que la perte de la diversité du bétail en Afrique fait partie de « l’effondrement » mondiale du cheptel. Selon l’Organisation des Nations Unies pour l’alimentation et l’agriculture, près de 20 % des 7 616 races de bétail existant dans le monde sont aujourd’hui considérées comme à risque.

« L’élevage africain est un des plus robustes au monde, et pourtant nous assistons aujourd’hui à une dilution, si pas une perte totale, de la diversité génétique de nombreuses races, » dit Abdou Fall, chef du projet diversité animale de l’ILRI pour l’Afrique de l’Ouest. « Mais aujourd’hui, nous avons les outils nécessaires pour identifier les caractéres de grande valeur du bétail africain indigène, une information qui peut être cruciale pour maintenir, voire augmenter la productivité de l’exploitation agricole africaine. »

M. Fall décrit les différentes menaces qui pèsent sur la viabilité à long terme de la production de bétail en Afrique. Ces menaces comprennent une dégradation du paysage et le croissement avec des races « exotiques » importées d’Europe, d’Asie et d’Amérique.

Par exemple, on assiste à un croisement sur une très large échelle de races des zones sahéliennes d’Afrique de l’Ouest et susceptibles aux maladies avec des races adaptées aux régions subhumides, comme le sud du Mali, et qui ont une résistance naturelle à la trypanosomiase.

La trypanosomiase tue entre trois et sept millions de tètes de bétail chaque année et son coût pour les exploitants agricoles se chiffre en milliards de dollars, lorsqu’on prend en compte, par exemple, les pertes de production de lait et de viande, et les coûts de médicaments et prophylactiques nécessaires au traitement ou à la prévention des maladies. Bien que le croisement puisse offrir des avantages à court terme, comme une amélioration de la production de viande et de lait ou une plus grande puissance de trait, il peut également faire disparaître des caractères très précieux qui sont le résultat de milliers d’années de sélection naturelle.

Les experts de l’ILRI déploient à l’heure actuelle des efforts importants en faveur d’une campagne visant à maîtriser le développement d’une résistance aux médicaments chez les parasites qui provoquent la trypanosomiase. Mais ils reconnaissent aussi que des races dotées d’une résistance naturelle à cette maladie offre une meilleure solution à long terme.

Ces races comprennent les bovins sans bosse et à courtes cornes de l’Afrique de l’Ouest et du Centre, qui ont vécu dans cette région avec ces parasites pendant des millions d’années et ont ainsi acquis une résistance naturelle à de nombreuses maladies, y compris la trypanosomiase, propagée par la mouche tsétsé, et les maladies transmises par les tiques. De plus, ces animaux robustes sont capables de résister à des climats rudes. Mais les races à courtes cornes et à longues cornes ont un désavantage : elles ne sont pas aussi productives que les races européennes. Malgré ce désavantage, la disparition de ces races aurait des conséquences graves pour la productivité future du bétail africain.

« Nous avons observé que les races indigènes sans bosse et à courtes cornes d’Afrique de l’Ouest et du Centre font l’objet d’un abatage aveugle et d’un manque d’attention aux bonne pratique d’élevage, et risquent ainsi de disparaître,» explique Fall. « Il faut qu’au minimum nous préservions ces races soit dans le contexte de l’exploitation, soit dans des banques de gènes : leurs caractéristiques génétiques pourraient en effet s’avérer décisives dans la lutte contre le trypanosomiase, et leur robustesse pourrait être un atout essentiel pour des exploitants agricoles qui auront à s’adapter au changement climatique. »

Le Kuri aux grandes cornes bulbeuses du Sud Tchad et du Nord-est du Nigéria fait partie des bovins africains à risques. Non seulement il ne se laisse pas déranger par les piqûres d’insecte mais il est également un excellent nageur, vu qu’il s’est développé dans la région du lac Tchad, et est idéalement adapté aux conditions humides dans des climats très chauds.

Les actions de l’ILRI en faveur de la préservation du bétail africain indigène s’inscrivent dans un effort plus large visant à améliorer la productivité de l’exploitation agricole africaine au travers de ce qu’on appelle la « génomique du paysage ». Cette dernière implique entre autre chose, le séquençage des génomes de différentes variétés de bétail provenant de plusieurs régions, et la recherche des signatures génétiques associées à leur adaptation à un environnement particulier.

Les experts de l’ILRI considèrent la génomique du paysage comme étant particulièrement importante vu l’accélération du changement climatique qui impose à l’éleveur de répondre toujours plus rapidement et avec l’expertise voulue à l’évolution des conditions de terrain. Mais ils soulignent qu’en Afrique en particulier, la capacité des éleveurs à s’adapter aux nouveaux climats va dépendre directement de la richesse du continent en termes de diversité de son cheptel indigène.

« Nous assistons trop souvent à des efforts qui visent à améliorer la productivité du bétail dans la ferme africaine en supplantant le cheptel indigène par des animaux importés qui à long terme s’avéreront mal adaptés aux conditions locales et vont demander un niveau d’attention simplement trop onéreux pour la plus part des petits exploitants agricoles, » dit Carlos Seré, Directeur général de l’ILRI. « Les communautés d’éleveurs marginalisées ont avant tout besoin d’investissement en génétique et en génomique qui leur permettront d’accroitre la productivité de leur cheptel africain, car ce dernier reste le mieux adapté à leurs environnements. »

M. Seré souligne la nécessité de nouvelles politiques qui encouragent les éleveurs et les petits exploitants agricoles africains à conserver les races locales plutôt que de les remplacer des animaux importés. Ces politiques, dit-il, devraient comprendre des programmes d’élevage centrés sur la l’amélioration de la productivité du cheptel indigène comme alternative à l’importation d’animaux.

Steve Kemp, qui dirige l’équipe de génétique et de génomique de l’ILRI, ajoute que les mesures de conservation en exploitation doivent également s’accompagner d’investissements en faveur de la préservation de la diversité qui permettront de geler le sperme et les embryons. On ne peut en effet exiger du seul exploitant agricole qu’il renonce à une augmentation de la productivité au nom de la conservation de la diversité.

« Nous ne pouvons pas attendre de l’exploitant qu’il sacrifie son revenu avec pour seul objectif de préserver le potentiel de diversité, » explique M. Kemp. « Nous savons que la diversité est essentielle pour relever les défis auxquels l’exploitant africain est confronté, mais les caractéres de grande valeur qui seront importants pour l’avenir ne sont pas toujours évidents dans l’immédiat. »

M. Kemp recommande une nouvelle approche pour mesurer les ressources génétiques du cheptel. Aujourd’hui, dit-il, l’estimation de ces caractéristiques porte essentiellement sur des éléments tels que la valeur de la viande, du lait, des œufs et de la laine, mais elle ne prend pas en compte d’autres attributs qui pourraient avoir une importance égale, voire supérieure, pour l’éleveur, qu’il soit en Afrique ou dans une autre région en développement. Ces attributs comprennent la capacité d’un animal à tirer la charrue, à fournir de l’engrais, à faire office de banque ou compte d’épargne ambulant, et d’être une forme efficace d’assurance contre les pertes de récolte.

Mais l’association de ces multiples attributs avec l’ADN d’un animal exige de nouveaux moyens pour rechercher et comprendre les caractéristiques du cheptel dans une région caractérisée par une grande diversité et une grande variété d’environnements.

« On dispose aujourd’hui des outils nécessaires, mais nous avons besoin de la volonté, de l’imagination et des ressources avant qu’il ne soit trop tard, » indique M. Kemp.
 

Experts warn rapid losses of Africa’s native livestock threaten continent’s food supply

N'DamaHerd_WestAfrica

Resilient disease-resistant, 'ancient' West African cattle, such as these humpless longhorn N'Dama cattle, are among breeds at risk of extinction in Africa as imported animals supplant valuable native livestock

Urgent action is needed to stop the rapid and alarming loss of genetic diversity of African livestock that provide food and income to 70 percent of rural Africans and include a treasure-trove of drought- and disease-resistant animals, according to a new analysis presented today at a major gathering of African scientists and development experts.

Experts from the International Livestock Research Institute (ILRI) told researchers at the 5th African Agriculture Science Week (www.faraweek.org), hosted by the Forum for Agricultural Research in Africa (FARA), that investments are needed now to expand efforts to identify and preserve the unique traits, particularly in West Africa, of the continent's rich array of cattle, sheep, goats and pigs developed over several millennia but now under siege. They said the loss of livestock diversity in Africa is part of a global 'livestock meltdown'. According to the United Nations Food and Agriculture Organization, some 20 percent of the world's 7616 livestock breeds are now viewed as at risk.

'Africa's livestock are among the most resilient in the world yet we are seeing the genetic diversity of many breeds being either diluted or lost entirely', said Abdou Fall, leader of ILRI's livestock diversity project for West Africa. 'But today we have the tools available to identify valuable traits in indigenous African livestock, information that can be crucial to maintaining and increasing productivity on African farms.'

Fall described a variety of pressures threatening the long-term viability of livestock production in Africa. These forces include landscape degradation and cross-breeding with 'exotic' breeds imported from Europe, Asia and the America.

For example, disease-susceptible breeds from West Africa's Sahel zone are being cross-bred in large scale with breeds adapted to sub-humid regions, like southern Mali, that have a natural resistance to trypanosomosis.

Trypanosomosis kills an estimated three to seven million cattle each year and costs farmers billions of dollars each year in, for example, lost milk and meat production and the costs of medicines and prophylactics needed to treat or prevent the disease. While cross-breeding may offer short-term benefits, such as improved meat and milk production and greater draft power, it could also cause the disappearance of valuable traits developed over thousands of years of natural selection.

ILRI specialists are in the midst of a major campaign to control development of drug resistance in the parasites that cause this disease but also have recognized that breeds endowed with a natural ability to survive the illness could offer a better long-term solution.

The breeds include humpless shorthorn and longhorn cattle of West and Central Africa that have evolved in this region along with its parasites for thousands of years and therefore have evolved ways to survive many diseases, including trypanosomosis, which is spread by tsetse flies, and also tick-borne diseases. Moreover, these hardy animals have the ability to withstand harsh climates. Despite their drawbacks—the shorthorn and longhorn breeds are not as productive as their European counterparts—their loss would be a major blow to the future of African livestock productivity.

'We have seen in the short-horn humpless breeds native to West and Central African indiscriminate slaughter and an inattention to careful breeding that has put them on a path to extinction', Fall said . 'We must at the very least preserve these breeds either on the farm or in livestock genebanks because their genetic traits could be decisive in the fight against trypanosomosis, while their hardiness could be enormously valuable to farmers trying to adapt to climate change.'

Other African cattle breeds at risk include the Kuri cattle of southern Chad and northeastern Nigeria. The large bulbous-horned Kuri, in addition to being unfazed by insect bites, are excellent swimmers, having evolved in the Lake Chad region, and are ideally suited to wet conditions in very hot climates.

ILRI's push to preserve Africa's indigenous livestock is part of a broader effort to improve productivity on African farms through what is known as 'landscape genomics'. Landscape genomics involves, among other things, sequencing the genomes of different livestock varieties from many regions and looking for the genetic signatures associated with their suitability to a particular environment.

ILRI experts see landscape genomics as particularly important as climate change accelerates, requiring animal breeders to respond every more quickly and expertly to shifting conditions on the ground. But they caution that in Africa in particular the ability of farmers and herders to adapt to new climates depends directly on the continent's wealth of native livestock diversity.

'What we see too often is an effort to improve livestock productivity on African farms by supplanting indigenous breeds with imported animals that over the long-term will prove a poor match for local conditions and require a level of attention that is simply too costly for most smallholder farmers', said Carlos Seré, ILRI's Director General. 'What marginalized livestock-keeping communities need are investments in genetics and genomics that allow them to boost productivity with their African animals, which are best suited to their environments.'

Seré said new polices also are needed that encourage African pastoralist herders and smallholder farmers to continue maintaining their local breeds rather than abandoning them for imported animals. Such policies, he said, should include breeding programs that focus on improving the productivity of indigenous livestock as an alternative to importing animals.

Steve Kemp, who heads ILRI's genetics and genomics team, added that in addition to conservation on the farm, there must also be investments in preserving diversity by freezing sperm and embryos because farmers cannot be asked to forgo productivity increases solely in the name of diversity conservation.

'We cannot expect farmers to sacrifice their income just to preserve the future potential of diversity', Kemp said. 'We know that diversity is critical to dealing with the challenges that confront African farmers, but the valuable traits that may be important in the future are not always immediately obvious.'

Kemp called for a new approach to measuring the characteristics of livestock genetic resources. Today, he said, these estimates focus mainly on such things as the value of meat, milk, eggs and wool and do not include qualities that can be of equal or even greater importance to livestock keepers in Africa and other developing regions. These attributes include the ability of an animal to pull a plough, provide fertilizer, serve as a walking bank or savings account, and act as an effective form of insurance against crop loss.

But associating this wider array of attributes with an animal's DNA requires new ways of exploring and understanding livestock characteristics in a region where there is so much diversity in so many different environments.

'The tools are available to do this now, but we need the will, the imagination and the resources before it is too late', Kemp said.

US$4.4 million awarded for research to build a climate model able to predict outbreaks of infectious disease in Africa

Cow suffering from trypanosomosis

Scientists at the University of Liverpool, in the UK, and the International Livestock Research Institute (ILRI), in Kenya, are working with 11 other African and European partners on a US$4.4-million (UK£3 million-) project to develop climate-based models that will help predict the outbreak and spread of infectious diseases in Africa.

The researchers are working to integrate data from climate modelling and disease-forecasting systems so that the model can predict, six months in advance, the likelihood of an epidemic striking. The research, funded by the European Commission Seventh Framework, is being conducted in Ghana, Malawi and Senegal. It aims to give decision-makers the time needed to deploy intervention methods to stop large-scale spread of diseases such as Rift Valley fever and malaria, both of which are transmitted by mosquitoes.

It is thought that climate change will change global disease distributions, and although scientists know a lot about the climate triggers for some diseases, they don’t know much about how far into the future these disease events can be predicted. This new project brings together experts to investigate the links between climate and vector-borne diseases, including ‘zoonotic’ diseases, which are transmissible between animals and humans.

ILRI veterinary researcher Delia Grace says that diseases shared by people and animals are under-investigated although they are critically important for public health. ‘Fully 60% of all human diseases, and 75% of emerging diseases such as bird flu, are transmitted between animals and people,’ she said.

ILRI geneticist Steve Kemp said that the project is making use of ILRI’s advanced genomics capacities to analyse pathogens from the field and to integrate the data collected on both pathogen distribution and climatic factors. ‘From ILRI’s point of view,’ Kemp said, ‘this project is particularly exciting because it brings strong climate and weather expertise that complements systems recently built by ILRI and its partners to detect outbreaks of Rift Valley fever and to determine its spread.’

The new project also complements ILRI’s ongoing work to better control trypansomosis in West African livestock, a disease transmitted by tsetse flies. Trypanosomosis, which is related to sleeping sickness in humans, causes devastating losses of animals—along with animal milk, meat, manure, traction and other benefits—across a swath Africa as big as continental USA. Members of the new modeling project will conduct research in some of the same locations as ILRI’s West African trypanosomosis project, Kemp explained, and work with some of the same partner organizations, which should generate synergies that benefit both projects.

The risk of epidemics in tropical countries increases shortly after a season of good rainfall—when heat and humidity allow insects, such as mosquitoes, to thrive and spread diseases. Matthew Baylis, from Liverpool’s School of Veterinary Science, explained how this works with Rift Valley fever: ‘Rift Valley fever can spread amongst the human and animal population during periods of heavy rain, when floodwater mosquitoes flourish and lay their eggs. If this rainfall occurs unexpectedly during the dry season, when cattle are kept in the villages rather than out on the land, the mosquitoes can infect the animals at the drinking ponds. Humans can then contract the disease by eating infected animals. Working with partners in Africa, we can bring this information together to build a much more accurate picture of when to expect epidemics.

Andy Morse, from Liverpool’s School of Environmental Sciences, said the project combines historical and contemporary climate data with disease incidence information, including that for vector-borne diseases, as well as integrating monthly and seasonal forecasts. The resulting single, seamless, forecast system, Morse said, should allow projections of disease risk to be made beyond the conventional predictable time limit. ‘All this information will be fed into a decision-support system to be developed with decision-makers on national health issues’ in the three target countries.

The project was launched at a conference at the University of Liverpool on 19 April 2010.

For more information, contact ILRI scientist Steve Kemp. ILRI email contacts are formatted as follows: f.surname@cgiar.org: replace ‘f’ with the staff member’s first initial and replace ‘surname’ with the staff member’s surname.

The 13 research partners:
Abdus Salam International Centre for Theoretical Physics (Italy), Centre de Suivi Ecologique (Senegal), Consejo Superior de Investigaciones Cientificas (Spain), European Centre for Medium-Range Weather Forecasts (UK), Fundació Privada Institut Català de Ciències del Clima (Spain), Institut Pasteur de Dakar (Senegal), International Livestock Research Institute (Kenya), Kwame Nkrumah University of Science and Technology (Ghana), Universitaet zu Koeln (Germany), University Cheikh Anta Diop de Dakar (Senegal), University of Liverpool (UK), University of Malawi (Polytechnic & College of Medicine), University of Pretoria (South Africa)