Already, we have seen 200 million pigs lost to African swine fever in China alone and it is estimated we will lose a quarter of the world's pig population to this virus. Hardest hit are small-scale producers who until recently supplied China with a third of its pork supply. Pork prices are at a record high, and this has contributed to inflation in China.
New research published in Nature Food has found an important link between trade and ensuring the resilience of global food systems, especially in the face of extreme events. In the case of African swine fever, researchers found that trade could reduce negative impacts, including pork shortages and price rises. Trade would allow global resources to be marshalled to respond to shortages in China by reallocating feed supplies to enable pork to be produced outside China, and pork substitutes such as beef and poultry to be boosted elsewhere.
For this research, CSIRO scientists, led by Daniel Mason-D’Croz, collaborated with the University of Oxford, the International Food Policy Research Institute, and the University of Sussex to model the global impacts of the African swine fever outbreak. Prior to the major outbreak in China, the researchers simulated what the impact of African swine fever would be on the rest of the world. Their modelling proved extremely accurate.
A deadly disease, for pigs
African swine fever, first recognised in Kenya in the early 1900s, reached China in 2018 with devastating impacts for the pig industry and backyard sector. The virus causes a contagious haemorrhagic fever that can kill infected pigs within a week.
Since 2018, the disease has spread from China to countries in Southeast Asia like the Philippines, Cambodia, Vietnam and Indonesia. Recently it was detected in Papua New Guinea. Although not yet in Australia, enhanced biosecurity measures are in place to prevent its introduction. The virus does not cause any harm to humans but means almost certain death to wild and domestic pigs.
There is currently no cure or vaccine for African swine fever however, CSIRO scientists are contributing to creating a vaccine by developing new methods for producing high concentrations of candidate African swine fever vaccine strains. This is so that when an effective vaccine is finally developed, it can be produced in the industrial quantities required.
As with COVID-19 in humans, the most effective measure to prevent the spread of African swine fever among pigs is to quickly identify and contain infections, as work continues and hopefully is accelerated to develop critical vaccines that can provide a long-term solution.
Modelling accurately reflects reality
In this study, the most obvious impact of African swine fever – a drastic decline in pork production in China – was simulated. The most severe scenarios that were modelled closely reflect how trends have subsequently developed; they projected an 85 per cent price rise in pork and what eventuated was a doubling of pork prices in China and prices in Europe increasing by about 50 per cent by the end of 2019.
Reduced pork supply has not only led to increased pork prices but also to consumers shifting to pork substitutes like beef, mutton and poultry, increasing their prices too. This shift and rising prices in pork substitutes were also projected in the modelling.
The researchers projected an increase in pork production outside of China along with a decline in pork consumption in response to higher prices, leading to increased exports from Europe and North America to China. Recent statistics show this is occurring.
Australia, as a major exporter of pork substitutes, including beef and mutton, and with strong historical trade links with China, has played its part, with increased exports of beef and mutton to China, helping to alleviate the shortage of animal sourced foods.
The close alignment between what was modelled to occur as a result of the spread of African swine fever and what is actually happening has highlighted the important role modelling can play in planning for disease outbreaks. Now more than ever is the value of modelling recognised, with daily predictions on the spread of COVID-19 in countries across the world.
There are many knock on effects from African swine fever. Most prominent is the reduced demand in China for feed sources like maize and soybeans with less pigs to feed, which led to price reductions for these commodities. Much of this feed which was grown for this purpose has been diverted to other uses, such as for increased beef production in North America, pork production in Europe and North America, and increased poultry production in North and South America.
Maize is not only an important feed crop, but also a key food staple, and the modelling suggests that consumers in countries where maize is a key food staple, such as in East Africa and Central America, may benefit from lower prices.
Not all food staples follow the same pathway as maize. Wheat, an important feed input into the livestock sector in Europe, saw increased demand to satisfy growing demand for pork substitutes, rising wheat prices and potentially negatively impacting countries where wheat is a key food staple, such as India.
In high income countries, such as Japan and the USA, where there is greater concern for over-consumption than undernourishment, these changes are unlikely to have a substantial impact on food security. In middle- and lower- income countries, particularly where pork is an important part of the diet, such as Vietnam and the Philippines, there is a greater risk of food security impacts.
Modelling helps plan for extreme events
Quantitative modeling and foresight analysis, such as was done in this study for African swine fever, helps policymakers develop contingency plans for future extreme events and market disruptions. It can also help to identify unexpected knock-on impacts (both positive and negative) in other regions and sectors.
There are few large-scale events that do not have ramifications that cross borders. COVID-19 is a classic example, as is African swine fever. In the 2007-08 food price crisis, exporting countries that implemented trade restrictions contributed to food prices spikes. As this research shows, the trade system is critical in helping to mitigate the worst impacts of extreme events, alleviating local shortages in key commodities, goods and services.