Trade in live animals and animal products : exploring global trends over a 20-year period using social network analysis

Objective(s): Trade networks facilitate and accelerate the spread of infectious diseases. To inform policy and ensure preparedness, it is essential to understand their structure and properties. This study analyses the temporal changes in global trade networks of live animals and animal products from 1997 to 2016.
Materials and methods: Data for selected commodities were retrieved from the United Nations International Trade Statistics Database. Weighted directed networks were created for each commodity and year aggregating all trade flows between two countries within one year into single links. Network properties and centrality measures were determined and compared over time to identify trends or changes.
Results: Global trade in meat of all livestock species increased steadily and was particularly high for poultry, while countries undergoing economic development showed rising demand for beef. Trade in live animals followed a similar pattern. All networks consisted of only one weakly connected giant component with a few central countries accounting for most of the volume of trade. Others maintained fewer and weaker trade relationships. Over time, the number and density of trade links increased steadily, while the clustering coefficient varied from year to year. High trading volumes were not always correlated with large numbers of trading partners.
Conclusions: Trade in live animals and animal products is increasing in line with the demands of a growing human population. The trend towards high connectedness in livestock and meat trade promotes the spread of infectious diseases and resistant pathogens, which requires new approaches to transboundary disease control and risk-based surveillance.