Category Archives: Disease Control

Under vaccines, we develop vaccines for livestock diseases, focusing especially on ways to improve immune responses to protozoa parasites. We also improve existing vaccines (ECF, CBPP) and develop molecular approaches to problems.

New outbreak of fatal Rift Valley fever in the Horn of Africa

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Rift Valley fever is a viral disease of people and ruminant animals transmitted by mosquitoes. Epidemics frequently present as extensive abortion storms in small ruminants and cattle combined with heavy mortality in young animals. In people, the disease is most often a febrile illness without serious consequences. In a low percentage of human cases (about 1% or less), hemorrhagic complications can arise. Blindness also occasionally results. 118 deaths have been confirmed since the outbreak in November 2006 in the North-eastern province and coastal region of Kenya.

The disease is transmitted by the bite of infected mosquitoes or heavy exposure to aerosols in situations such as the slaughtering of infected animals. Outbreaks of the disease are associated with changes in local water resource management or periods of heavy rainfall. Examples have been the construction of new dams or El Nino rain events such as the one in East Africa in 1997-98 when there was a major outbreak of Rift Valley fever in Kenya and Somalia. The virus has been shown to over-winter in infected mosquito eggs. At the onset of the rains, infected mosquitoes transmit the disease to suitable amplifying hosts such as small ruminants. If vector densities are sufficiently high due to favourable environmental conditions, this starts a cascade-like recrudescence of the virus in the host and vector populations, leading to an epidemic.

Severe human cases, although an infrequent outcome of infection, are often the event that triggers recognition that an epidemic is under way.  There is need to develop early warning systems and to validate prevention and control strategies that can mitigate the evolution of outbreaks. Rift Valley fever causes serious economic losses in livestock particularly in cattle and sheep, although goats, camels, Asian water buffalo and wild antelopes may be vulnerable.

Key research questions

A number of important research questions related to Rift Valley fever and its impact remain unanswered and worthy of further research.  These include the following:

•  What is the economic impact of an RVF outbreak, particularly in terms of distribution, livelihoods, international trade, public health, and other macro-level factors?  How does the disease affect unrelated sectors (e.g., tourism)?
•  How has the disease broadly affected trade patterns in livestock products from the horn of Africa and what are potential future impacts? How can these be mitigated?
•  How effective are current vaccines in their ability to prevent disease and how frequent are side effects? There are two types of vaccines currently in use, both of which have serious disadvantages.  For human use, a ‘killed vaccine’consists of formalin-inactivated virus for restricted use.   It requires several doses and annual revaccination.  It is not approved for general distribution and is used only for laboratory workers and other specialized groups.  A live, attenuated vaccine is approved for use in livestock.  It induces a solid, life-long immunity but may cause abortions if administered to pregnant animals. 
•  What is the epidemiological impact and cost-effectiveness of alternative types of vaccination and movement control strategies?  How can these tools be best used in the face of outbreaks like the one we are experiencing now?
•  Can diagnostic tests for the disease be improved to make them more ‘user-friendly’ for field workers and remote laboratories?  Is it possible to develop good diagnostic tests to distinguish between active and past infections, and to distinguish previously exposed animals from vaccinated animals?
•  How can we enhance decision-making and promote the application of risk-based standards to ensure safe international trade of livestock products and scientifically sound trade restrictions?

 The Nairobi-based International Livestock Research Institute (ILRI) is actively seeking to become engaged in two areas.

In diagnostics, ILRI recently held discussions with the Kenya’s Department of Veterinary Services and South Africa’s Onderstepoort Veterinary Institute (OVI).  OVI have developed a field-based test to diagnose RVF infection in cattle.  This test requires only the application of a small blood sample to the device with a result obtained in about three minutes.  Such a test has advantages over a laboratory-based test, in terms of speed of diagnosis and no need for electricity or other equipment.  Although the test has profed successful in the laboratory, it has yet to undergo extensive testing in the field to ensure that it is sufficiently accurate.  It is envisaged that ILRI will be involved in this testing, using samples from the current outbreak.

On another front, ILRI is pursuing the possibility of working with a Walter Reed Project (WRP) and the US-based Centers for Disease Control (CDC) to support their ongoing efforts to understand and control this present outbreak of Rift Valley Fever.  Internal discussions within ILRI highlight three key areas in which ILRI could contribute in this process:

• Sensitise key stakeholders, particularly in government of the epidemiological and economic magnitude and impact of the current outbreak in Kenya.
• Initiate a process to identify appropriate veterinary control strategies to reduce both animal   and human incidence of the disease
• Take advantage of the current situation to collect key epidemiological and economic data to guide further research and improve risk mitigation tools

ILRI is in discussions with the WRP-CDC teams to define roles specific for ILRI in the areas of assessing the socio-economic impacts of the disease, participatory epidemiology and surveillance, and the interface between livestock and public health.  ILRI aims to help WRP-CDC in their short-run emergency response efforts as well as to use this current outbreak to help design decision-support tools to better manage future occurrences of Rift Valley Fever.

Community animal health services beat disease and poverty in Ghibe Valley, Ethiopia

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Click on the title above for the story and view the accompanying slideshow on the right.

Sleeping sickness transmitted by Africa’s tsetse flies is arguably the major livestock disease and one of the major constraints to crop production across the fertile lowlands of Ethiopia. This wasting disease maims and kills dairy cows that provide households with regular income, food for children and draft oxen that allow farmers to open up and work the land. The nearest animal health facilities are far from the Ghibe Valley, in southwestern Ethiopia, where the disease has been endemic, and cannot provide the communities that live there with veterinary services when their animals get sick. This vast and fertile land, once held hostage to this disease, has ‘come back’, with crop production and animal husbandry intensified by control of animal sleeping sickness.

Twenty years of work by ILRI in the region, which started as a research project, has recently been transformed into community-led livestock disease control. A three-year ILRI project funded by COMART, a private Canadian foundation, in the Ghibe Valley has resulted in the formation of animal health ‘cooperatives’. Four communities have developed their own animal health services. Members contribute money to a revolving fund used to buy veterinary drugs to control animal sleeping sickness. ILRI and the Wereda Bureau of Agriculture have been helping the new cooperatives prepare work plans as well as to buy and apply the drugs. The scheme is highly successful. Hundreds of farmers line up every month to pay for the treatments, the drugs demonstrably improve the health of their livestock, and neighbouring communities are asking for support to set up similar services in their areas. A network that formed early among the participating communities and cooperatives allows stake­holders in the project to learn from each other quickly. This farmer-to-farmer knowledge transfer is now speeding the scaling out of these community-based schemes to control livestock disease.

Click here for all images and related captions on the Ghibe slideshow.

Increasing developing-country livestock trade without increasing disease

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Livestock sellers in Mozambique

Are there opportunities for greater trade of livestock products from developing countries without increasing the risk of spreading animal diseases?

A new study from the International Livestock Research Institute (ILRI) and the Food and Agriculture Organization of the United Nations (FAO) suggests that there are and lays out a series of recommendations as to how they might be achieved. Livestock is one of the key assets of most developing countries, but compared to other agricultural products, this resource is currently significantly underutilised as a tool for poverty reduction. One of the reasons behind this is that many developing countries still harbour animal diseases that present a risk to the West, where diseases such as foot and mouth disease (FMD) and classical swine fever (CSF), to name but two, have been eradicated. Their reintroduction to countries free of these diseases has disastrous economic and environmental consequences. This dichotomy presents yet another example of the widening divide between developed and developing countries. So how can developing countries make better use of their livestock resources through greater market access in the world without putting developed countries at greater risk? This topic has been the subject of a study recently undertaken by ILRI on behalf of FAO, the report of which was released in July 2005.

Entitled ‘An appropriate level of risk: balancing the need for safe livestock products with fair market access for the poor’, the report questions some of the ground rules for safe international trade in livestock commodities, while at the same time identifying specific needs for human resource capacity development to safeguard the animal health and food safety integrity of livestock commodity value chains. Led by ILRI’s veterinary epidemiologist Brian Perry, the study identified some market successes, and some failures, in the regions of South East Asia, eastern and southern Africa and Central America, drawing from them some key lessons of global significance.

Read the complete report: http://www.fao.org/ag/againfo/programmes/en/pplpi/docarc/wp23.pdf

Vets without frontiers: Doing it better

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VSF-Belgium and ILRI have teamed up in an innovative partnership arrangement that could serve as a super highway between livestock research and development activities in the field. Here the 'implementers' and the 'research & developers' have joined forces to "do it better together" to better serve the poor livestock keeper. VSF-Belgium and ILRI have teamed up in an innovative partnership arrangement that will facilitate communications between livestock farmers, veterinary scientists and vets in the field, and ultimately increase the impact of research. Dr Bruno Minjauw, Operational Project Leader of Innovative Partnerships at ILRI, has been appointed as VSF-Belgium's Regional Director – East Africa. Dr Minjauw will hold a joint position with ILRI and VSFB sharing his time between both organisations. Dr Minjauw said: "I am delighted with this appointment – this is new and exciting territory for all involved. ILRI and VSFB have similar and complementary missions – so this partnership makes sense. We are both trying to do the same thing – and I believe we can do it better together. Ultimately this partnership provides ILRI with a unique asset – a direct door to the voice of the poor." Els Bedert, Programme support for East Africa, of VSFB said: "What really excites us about this partnership with ILRI is that we now have a direct link to the livestock research component. Our (VSF) vets are on the ground working with poor farmers. Having access to scientists with the latest knowledge and resources is going to add considerable value to our role. Essentially, we can act as a link between the farmers and scientists and the scientists and the farmers." The new ILRI-VSF partnership has the potential to identify VSF activities that could benefit from existing information, methodologies and scientific expertise at ILRI, as well as identifying existing ILRI activities where VSF could play a role to increase the impact of research. So what does this mean in practice? Amongst other activities, VSFB is actively involved in a programme which aims to train farmers in basic veterinary skills and provide communities with treatments and vaccinations for their animals through an established decentralised animal health service, whilst also training community animal health workers on how to administer those drugs. VSFB have clear exit strategies built into their programs, so livestock keepers do not become dependent on them. Rather than offering drugs as 'handouts', VSF are making veterinary drugs more readily available for farmers to purchase. One example of the benefits of this new partnership is that VSF vets might identify that a particular technology, which could have a major impact if used by the farmers, is too expensive or in some way inappropriate, therefore farmers will not adopt it. VSFB could then inform ILRI and its partners of the situation and they could then look into ways of improving the technology, either by making it more appropriate or available at a lower cost, or even looking into alternatives, in order to encourage greater uptake by farmers. Similarly, scientists might find that adoption rates of a new technology is low and/or having little impact. VSF vets would be well placed to help establish why this is the case and could then feed back this information to scientists. These are just a couple of opportunities that could be seized to increase the impact on the ground. Vétérinaires Sans Frontières Europa (VSF Europa) is a non-profit international association comprising 8 European VSFs, including VSF-Belgium. Field activities are part of the VSF global programme and their mission is to improve the well-being of vulnerable populations in developing countries, by improving animal health and production. VSFB activities are mainly in three geographical areas in Africa – the Horn of Africa, the Great Lakes region and sub-Saharan countries in West Africa.