Global trends in infectious diseases of swine

Dr. Kim VanderWaal and Dr. John Deen from the University of Minnesota co-authored a new publication available now in the Proceedings of the National Academy of Sciences of the United States of America.

The objectives of this study were to identify priority swine pathogens, characterize temporal and geographic trends in research priorities.

57,471 publications covering 40 swine pathogens, compiled from 3 major database searches and dating from 1966 to 2016 were included in this analysis.

The top 10 pathogens published on were:

  • Salmonella spp.
  • Escherichia coli
  • Influenza
  • Pseudorabies
  • Foot and Mouth Disease
  • Porcine Reproductive and Respiratory Syndrome
  • Classical Swine Fever
  • Actinobacillus pleuropneumoniae
  • Trichinella spp.
  • African Swine Fever

The number of publications on swine infectious diseases increased over time as the hog production intensified. However, 8 pathogens increased faster than expected, particularly in the past 15 years: hepatitis E virus, Nipah virus, influenza, Streptococcus suisLawsonia intracellularis, porcine circovirus 2, PRRS, and PED.

On the contrary, some diseases had a slower growth in number of publications than expected. These included pseudorabies, Pasteurella multocida, Actinobacillus pleuropneumoniae, Brachyspira hyodysenteriae, and transmissible gastroenteritis virus. All of these pathogens were production diseases whose importance to the industry had declined in recent decades due to better control or even regional eradication.

Differences among world regions were identified except for influenza virus which appeared in the top 5 in most regions of the world. Southern regions where extensive hog production may still be the norm, tended to focus more on parasitic infections compared to Northern areas. Western Europe centered more on pathogens related to zoonotic and foodborne concerns compared to Northern America.

Read more about the evolution of publications on swine infectious diseases around the world.

Abstract

Pork accounts for more than one-third of meat produced worldwide and is an important component of global food security, agricultural economies, and trade. Infectious diseases are among the primary constraints to swine production, and the globalization of the swine industry has contributed to the emergence and spread of pathogens. Despite the importance of infectious diseases to animal health and the stability and productivity of the global swine industry, pathogens of swine have never been reviewed at a global scale. Here, we build a holistic global picture of research on swine pathogens to enhance preparedness and understand patterns of emergence and spread. By conducting a scoping review of more than 57,000 publications across 50 years, we identify priority pathogens globally and regionally, and characterize geographic and temporal trends in research priorities. Of the 40 identified pathogens, publication rates for eight pathogens increased faster than overall trends, suggesting that these pathogens may be emerging or constitute an increasing threat. We also compared regional patterns of pathogen prioritization in the context of policy differences, history of outbreaks, and differing swine health challenges faced in regions where swine production has become more industrialized. We documented a general increasing trend in importance of zoonotic pathogens and show that structural changes in the industry related to intensive swine production shift pathogen prioritization. Multinational collaboration networks were strongly shaped by region, colonial ties, and pig trade networks. This review represents the most comprehensive overview of research on swine infectious diseases to date.