Aminopeptidase N (ANPEP, or CD13) is considered an entry mediator for pig coronaviruses, and 4 integrins (αvβ1, αvβ3, αvβ6, and αvβ8) and heparan sulfate are known receptors of the virus; no single major-effect resistance gene has been validated for these infections [35]. The gene discussed is ANPEP; the disease is infection.