Peer-review started: June 29, 2015
First decision: August 16, 2015
Revised: February 22, 2016
Accepted: March 14, 2016
Article in press: March 26, 2016
Published online: March 27, 2016
Processing time: 274 Days and 11 Hours
Five major porcine coronaviruses (COVs) have been identified which cause severe gastrointestinal (GI) and respiratory disease in pigs. They include transmissible gastroenteritis (TGEV), porcine epidemic diarrhea virus (PEDV), porcine deltacoronavirus, porcine respiratory coronavirus, and porcine hemagglutinating encephalomyelitis. These diseases, especially TGEV and PEDV, have caused epidemics in Europe, Asia, and the Americas over the past 50 years, causing significant economic losses to swine producers. As pigs are a major protein source worldwide there is great interest in understanding, controlling, and preventing these diseases. These diseases have no cure, and current vaccines are not fully protective. On-farm prevention and biosecurity are difficult to enforce and have not stopped the spread of these diseases between herds. Recent advances in the immunology of porcine COVs has revealed that the immune response to porcine COVs shares many similarities with the response to human COVs, leading to increased interest in pigs as models for human disease. Highlights of these advances include the key role of local antigen presenting cells in the gastrointestinal tract in stimulating a protective immune response. This understanding has lead to new proposed vaccines. Advances in the understanding of the ways the viruses evade and degrade the host immune system have also lead to novel proposed therapies. Many of these therapies are in the early development stages, as researchers attempt to create efficacious, cost-effective, and practical therapies for these diseases.
Core tip: Coronaviruses (COVs) cause severe disease in both pigs and humans. New immunological research in pigs has revealed many similarities between porcine and human responses to COVs. Understanding the immunological responses of pigs to COVs may prove that they are a viable human model to study these diseases, as well as providing new and more efficacious control mechanisms for veterinarians and swine producers worldwide.