Some scholars have considered that the onset of porcine enzootic pneumonia depends on Mhp virulence factors, which enable the pathogen to evade host defense mechanisms, as well as on the production of molecules that participate in processes including cell–host adhesion, response to environmental stress in the host, and immune regulation (Leal Zimmer et al., 2020). This evidence concerns the gene CACNA1A and susceptibility to pneumonia measurement.