The UN Food and Agriculture Organisation has called for immediate action and a change of focus to combat the "surge in diseases of animal origin" around the world.

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The FAO call was made on Monday, less than one month after livestock-associated MRSA was found for the first time in poultry in the UK.

On Monday, FAO said population growth, agricultural expansion, and the rise of globe-spanning food supply chains have dramatically altered how diseases emerge and ways in which they can spread, jumping form one species to another and crossing 'hard' boundaries such as rivers, seas and mountain ranges. The UN Organisation issued a report on the issue, and said a new, more holistic approach to managing disease threats is needed.

FAO's calls echo pleas made by a number of expert scientists, including a team who last month demanded that governments tackle irresponsible and over-use of antibiotics, which they said is contributing to the growing numbers of antibiotic resistant 'superbugs'. Their calls followed the publication of a report in medical journal Lancet Infectious Diseases, which was amongst the first to make the link between antibiotic resistance in agriculture and that seen in human medicine.

The paper's authors also demanded a holistic approach to the issues of disease and resistance. They said, "A way forward would be to acknowledge that human health, animal health, and the environment are all interlinked, and that the responsibility for dealing with the problems of resistance is shared by all stakeholders."

FAO report sheds worrying light on new disease threats

Seventy percent of the new diseases that have emerged in humans over recent decades are of animal origin and, according to FAO, many can be linked to animal agriculture.

The new UN report, World Livestock 2013: Changing Disease Landscapes, Suggests that ongoing expansion of agricultural lands into previously '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."

Commenting on Monday, Ren Wang, a senior FAO spokesperson, backed the calls of the scientists from the Lancet. He said, "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."

Wang added that the need for action is pressing, as developing countries are facing "a staggering burden of human, zoonotic and livestock diseases." These diseases are not only a burden and impediment to development and food safety in the places they originate, but in many cases they risk spreading around the world. FAO said recurrent epidemics in livestock affect food security, livelihoods, and national and local economies in poor and rich countries alike.

World Livestock 2013 finds that changes wrought by human activity have created a vastly more complicated global disease landscape in recent years, and that in some regions "Ongoing population growth and poverty - coupled with inadequate health systems and sanitation infrastructure - remain major drivers in disease dynamics."

Animal origins of new disease threats

The FAO report gives examples of diseases with origins in wild animals, which have often reached human populations through agriculture. It is likely that the SARS virus, which caused widespread panic around the world in late 2002, was first transmitted by bats to masked palm civets and eventually spilled over to humans via domesticated animals. Another is H5N1 avian flu, a virulent flu strain prone to mutation, the first known human cases of which were associated with an outbreak in Hong Kong's poultry industry.  

The report also points out that the opposite of this can and does occur; livestock may introduce pathogens to wildlife. The Rome-based agriculture organisation added that climate change and increasing human mobility will also change the habitat and survival rates of different diseases.

The role of livestock

The risk of animal-to-human spread of disease varies greatly according to the type of livestock production and the presence of basic infrastructure and services, according to the report.

FAO authors noted that, as intensive production at large scale involves the congregation of large numbers of genetically identical animals, when biosecurity measures fail or resistance to antibiotics develops, pathogens can mutate and spread rapidly along the food chain. However, intensive farms are not the only ones that present a disease risk.

Smallholder livestock systems - which tend to involve animals roaming freely over larger areas, can also play a part in spreading disease.

On Monday, FAO called for a "One Health" approach - looking at the interplay between environmental factors, animal health, and human health and bringing human health professionals, veterinary specialists, sociologists, economists, and ecologists together to work on disease issues within a holistic framework. At the same time, the findings of the FAO report suggest "livestock health is the weakest link in our global health chain. Disease must be addressed at its source - particularly in animals."

FAO's report identifies four main fronts for action:

• Reducing poverty-driven endemic disease burdens in humans and livestock
• Addressing the biological threats driven by globalization and climate change
• Providing safer animal-source food from healthy livestock and agriculture
• Preventing disease agents from jumping from wildlife to domestic animals and humans.

In particular, the UN agency said assembling better evidence on the drivers of animal disease must be top priority, and the resulting analyses must focus attention on improving risk assessment and prevention measures.