ROME, Dec. 16, 2013 – Population growth, agricultural expansion, and the rise of globe-spanning food supply chains have dramatically altered how diseases emerge, jump species boundaries, and spread, according to an FAO report released today. A new, more holistic approach to managing disease threats at the animal-human-environment interface is needed, it argues.
Seventy percent of the new diseases that have emerged in humans over recent decades are of animal origin and, in part, directly related to the human quest for more animal-sourced food, according to the report, World Livestock 2013: Changing Disease Landscapes.
The ongoing expansion of agricultural lands into wild areas, coupled with a worldwide boom in livestock production, means that "livestock and wildlife are more in contact with each other, and we ourselves are more in contact with animals than ever before," said Ren Wang, FAO assistant director-general for Agriculture and Consumer Protection.
"What this means is that we cannot deal with human health, animal health, and ecosystem health in isolation from each other - we have to look at them together, and address the drivers of disease emergence, persistence and spread, rather than simply fighting back against diseases after they emerge," he added.
FAO's new report provides a number of reasons for taking a new direction on disease emergence.
Developing countries face a staggering burden of human, zoonotic and livestock diseases, it says, creating a major impediment to development and food safety. Recurrent epidemics in livestock affect food security, livelihoods, and national and local economies in poor and rich countries alike.
Meanwhile, food safety hazards and antibiotic resistance are on the increase worldwide.
Globalization and climate change are redistributing pathogens, vectors, and hosts, and pandemic risks to humans caused by pathogens of animal origin present a major concern.
FAO's new study focuses in particular on how changes in the way humans raise and trade animals have affected how diseases emerge and spread.
"In response to human population growth, income increases and urbanization, world food and agriculture has shifted its main focus from the supply of cereals as staples to providing an increasingly protein-rich diet based on livestock and fishery products," World Livestock 2013 notes.
While livestock production provides a number of economic and nutrition benefits, the sector's rapid growth has spawned a number of health-related challenges, according to the report.
The risk of animal-to-human pathogen shifts varies greatly according to the type of livestock production and the presence of basic infrastructure and services.
While intensive production systems are largely free from high-impact animal and zoonotic diseases, they do present some pitfalls, particularly in developing countries and countries in transition, according to the report.
Intensive production at large scale involves the congregation of large numbers of genetically identical animals. Strong biosecurity and health protection regimes generally prevent infectious disease problems, but major outbreaks occur occasionally when a pathogen performs a virulence jump, escapes the vaccine used, acquires resistance to antibiotics, or travels along the food chain.
The report also states, however, that disease emergence in livestock is not specific to large-scale, intensive systems.
Smallholder livestock systems - which tend to involve animals roaming freely over large areas, but still in relatively high densities - often facilitate the disease spread, both among local animal populations and over broad distances.
To address this and other problems, FAO’s report pushes for a worldwide effort to assemble better evidence on the drivers of animal disease. The resulting analyses must focus attention on improving risk assessment and prevention measures, it says.
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