The mice inoculated with EF3030 and active PIV contained by day 2 post-infection less than 50 pg/mL of IL-22 in the lung homogenate whereas lungs infected with EF3030 alone, EF3030 plus heat-inactivated PIV, or EF3030 plus LasB contained approximately three-fold more IL-22 (i.e., 120 to 170 pg/mL). This evidence concerns the gene IL22 and infection.