Orma Boran cattle crossing a river in Kenya

Orma Boran cattle crossing a river in Kenya (photo credit: ILRI/Rosemary Dolan).

The Dynamic Drivers of Disease in Africa Consortium is a research program that works to understand the relationships between ecosystems, zoonotic diseases, health and wellbeing in order to inform effective public health interventions.

Under this program, multidisciplinary country teams are studying four zoonotic diseases: henipavirus infection in Ghana, Lassa fever in Sierra Leone, Rift Valley fever in Kenya and trypanosomiasis in Zambia and Zimbabwe. The focus is on how changes in biodiversity, land use and climate affect disease transmission.

The development of irrigation schemes is thought to influence pathogen transmission in people and animals in several ways. For example, masses of stagnant water and high humidity support the development of disease vectors like mosquitoes. In addition, irrigated areas are likely to have a higher density of animal hosts like chicken and small ruminants.

In order to investigate the influence of irrigation and changes in biodiversity on the distribution of zoonoses, a cross-sectional study was carried out in Tana River County, Kenya, home to the Hola Irrigation Scheme. The zoonoses of interest were Rift Valley fever, Q fever, brucellosis, West Nile virus, dengue fever and leptospirosis.

Irrigation causes a decline in biodiversity as wildlife habitats are cleared to make way for crop agriculture. However, the linkages between biodiversity and disease risk remain unclear. It was also found that areas with a rich diversity of hosts have higher prevalence of multiple zoonotic pathogens as compared to areas with lower host diversity.

The study also found that while irrigated areas are infested with multiple species of mosquitoes (including primary vectors of Rift Valley fever), their high population densities alone are not enough to sustain the transmission of pathogens; reservoir hosts (for example, birds for West Nile virus) or other persistence mechanisms are required.

These and other findings from the study were presented at the 49th annual scientific conference of the Kenya Veterinary Association which was held in April 2015.

View the presentation, Land use, biodiversity changes and the risk of zoonotic diseases: Findings from a cross-sectional study in Tana River County, Kenya

Maasai father and son tend to their cattle in Kenya

Maasai father and son tend to their cattle in their paddock in Kitengela, Kenya (photo credit: ILRI/Stevie Mann).

Zoonoses account for 60% of human diseases, but traditional divisions between human, livestock and environmental health sectors undermine their control. This has led to calls for greater intersectoral cooperation through an approach known as One Health.

The cover story of the December 2014 – January 2015 issue of CTA’s Spore magazine focuses on the One Health approach to tackling zoonoses and highlights some examples of One Health research by the Food Safety and Zoonoses program at the International Livestock Research Institute (ILRI).

Read the Spore article, Together in sickness and health

Typical mixed crop-livestock farming in western Kenya

Typical mixed crop-livestock farming in western Kenya. Mixed crop-livestock farming systems currently produce most of the world’s meat, milk and staple crops (photo credit: ILRI/Pye-Smith).

The January 2013 issue of Animal Frontiers, the world’s premier review magazine in animal agriculture, features a series of articles on the contribution of animal agriculture to global food security.

The International Livestock Research Institute (ILRI) has contributed to this series with a position paper that highlights the direct and indirect effects of livestock on food and nutrition security. The paper also considers the future prospects of mixed crop-livestock farming systems that produce most of the world’s milk, meat and staple crops.

The paper by ILRI director general Jimmy Smith and colleagues begins with a brief overview of the global challenge of food and nutrition security and the net impact of livestock on global food supply. This is followed by a review of the direct contributions of livestock to nutrition security and the indirect effects of livestock on food security.

Food security is said to exist when “all people at all times have access to sufficient, safe, nutritious food to maintain a healthy and active life”. In development discourse, the term ‘food security’ is often used to emphasize the aspect of food quantity while ‘nutrition security’ captures the quality dimension.

The position paper offers a balanced analysis by exploring both the beneficial impacts (e.g. improved nutrition and health, income from the sale of animals or produce, draught power and provision of manure) and the harmful ones (e.g. zoonotic diseases, health risks from over-consumption of animal-source foods and production of greenhouse gases).

“Livestock contribute to food supply by converting low-value materials, inedible or unpalatable for people, into milk, meat, and eggs; livestock also decrease food supply by competing with people for food, especially grains fed to pigs and poultry. Currently, livestock supply 13% of energy to the world’s diet but consume one-half the world’s production of grains to do so.

However, livestock directly contribute to nutrition security. Milk, meat and eggs, the “animal-source foods,” though expensive sources of energy, are one of the best sources of high quality protein and micronutrients that are essential for normal development and good health. But poor people tend to sell rather than consume the animal-source foods that they produce.

The contribution of livestock to food, distinguished from nutrition security among the poor, is mostly indirect: sales of animals or produce, demand for which is rapidly growing, can provide cash for the purchase of staple foods, and provision of manure, draft power, and income for purchase of farm inputs can boost sustainable crop production in mixed crop-livestock systems.

Livestock have the potential to be transformative: by enhancing food and nutrition security, and providing income to pay for education and other needs, livestock can enable poor children to develop into healthy, well-educated, productive adults. The challenge is how to manage complex trade-offs to enable livestock’s positive impacts to be realized while minimizing and mitigating negative ones, including threats to the health of people and the environment.”

On the future role of mixed crop-livestock farming systems, the authors note that it is important to look into issues related to production efficiency as well as market engagement in defining how these systems are to evolve in order to remain competitive, equitable and environmentally stable while continuing to contribute to human nutrition and health.

The paper concludes:

“Many poor livestock keepers report that a key motivation for keeping livestock is to earn income so their children can attend school and, perhaps, go on to benefit from further education. By providing essential nutrients, especially in the first critical 1,000 days from conception, animal-source foods can help ensure normal physical and cognitive development.

The combined impacts of meeting nutritional needs and providing income make livestock a powerful force for the poor. Well-nourished and well-educated youngsters can grow up to be healthy young adults who are able to realize their full potential and earn higher incomes, in the process enhancing the well-being of their families, communities, and society. The impact of this on food and nutrition security at household, national, and global levels cannot be overstated and demands innovative research, development, and policy approaches.”

Read the full article here

Citation: Smith J, Sones K, Grace D, MacMillan S, Tarawali S and Herrero M. 2013. Beyond milk, meat, and eggs: Role of livestock in food and nutrition security. Animal Frontiers 3(1): 6-13.