FIG. 4.
Results of in vivo virulence assessment study 2. Tracheal lesion scores (A) and tracheal mucosal thicknesses (B) were determined for chickens inoculated with strain P1H9, 2162, 2204, or Rlow of M. gallisepticum or with Hayflick's medium alone. (−), medium-inoculated group (negative control). The 25th percentiles, medians, and 75th percentiles are represented by box plots, and letters indicate statistically similar groups, using Dunn's or the Student-Newman-Keuls method. (C) Recovery of M. gallisepticum from chicken tracheas. The y axis indicates the maximum number of cells recovered given the highest serial dilution exhibiting a color shift for a given chicken. (Note that data are not presented for 1 bird from the mutant 2204-inoculated group that was determined to be a statistical outlier, nor are recovery data presented for 1 bird from the mutant 2164-inoculated group that was determined to be contaminated.)