Revisiting EFSA@EXPO: emerging issues in animal and plant health
The risk from emerging pests and pathogens has increased as a consequence of global changes to the way food is produced and consumed. In addition, climate change is likely to increase pressure on the availability of food. It will also provide newly suitable conditions for invasive species, pests and pathogens. Population displacement due to economic, political and humanitarian crises represents another potential driver for emerging issues. This session looked at the cultural and methodological shifts we must make if we are to deal with emerging risks.
People, animals, plants, pests and pathogens: connections matter
William Karesh, of the EcoHealth Alliance in the US, opened by suggesting that an alternative title for his talk could be “You get what you eat”. Emerging infectious diseases are on the rise, but what is driving them? With this question he set the scene for the session. And the answer? Dr Karesh identified three main drivers: changes in land use, changes in agricultural practices, and the boom in international travel and commerce. He illustrated his point with hot-spot maps, and examples such as how demand for palm oil has led to widespread deforestation.
Relations between pathogens, hosts and environment: joining the dots
Matthew Baylis of Liverpool University explained how the concept of a “pathogen network” is central to understanding zoonotic diseases. How are pathogens shared, he asked. Hosts may live together, be closely related, or eat one another. The main transmission routes are the environment, sexual activity, and food. Echoing William Karesh, he argued that to understand zoonotic patterns we have to identify the drivers of animal diseases such as foot and mouth, avian influenza, and African swine fever.
Discovering novel pathways of cross-species pathogen transmission
Nature used to be fun, said Tony Goldberg, of the University of Wisconsin-Madison, but then the narrative changed, and nature became less magical and more microbial. This change led him to study primates in a biodiversity hotspot in Uganda, where primates have been going extinct in part due to infectious diseases. Prof Goldberg went “virus hunting”, and made some exciting but worrying discoveries. He said that, in trying to work out which viruses will cross over, the best route to take is “pathway discovery” – to find unknown routes of pathogen transmission. We must also go “beyond bushmeat” and look at other modes of interaction between humans and primates – such as accidental contact, rogue animals, and animals being killed by dogs or children.
Broad brush analysis of livestock disease drivers, ecology and pathogen evolution
Jan Slingenbergh, an independent adviser, began by saying that livestock pathogens are a new phenomenon – about 12,000 years old. He traced the growth in demand for animal protein, highlighting two peaks – the industrial revolution of the mid-19th century and then the “livestock revolution” of the 1990s, which was characterised by a rapid growth of animal protein production around the world, featuring mass rearing of “monoculture” animals. He concluded by arguing that if our ambition is to ensure sustainable livestock production, then we must re-examine what kind of food we really want and how we produce it.
Horizon scanning for emergence of new viruses in animal and public health
Paul Gale of the UK Animal and Plant Health Agency summed up horizon scanning as being about “getting the right experts together and talking to each other”. Spotting emerging problems is increasingly difficult because the world is changing and viruses are changing. Take, for example, Schmallenberg virus, which before “arriving” in 2011 was not even mentioned in textbooks. Were weak signals missed, Dr Gale asked. As well as understanding drivers and pathways, it is important to look for combinations of events, he explained. For example, what connects the use of an anti-inflammatory drug in cattle with a rise in rabies cases in Italy? Or people building swimming pools in California, the financial crash, and West Nile virus? He advocated greater use of spidergrams to bring together factors such as land use, farming practices, and socio-economic changes to help predict coming zoonotic events.