TABLE 1.
Comparison of virulence parameters for infections with wild-type and pbmif-ko parasitesa
| Host mice | Variable | Test statistics | Further details |
|---|---|---|---|
| BALB/c | Cumulative parasite density | F(1,8) = 0.59; P = 0.464 | Wild type infections: 1.04 ± 0.15 |
| pbmif-ko1 infections: 0.68 ± 0.16 | |||
| Peak parasitemia | F(1,8) = 5.00; P = 0.056 | Wild type infections: 7.24 ± 1.03 | |
| pbmif-ko1 infections: 4.88 ± 1.20 | |||
| Minimum mass | F(1,8) = 3.04; P = 0.119 | Wild type infections: 17.74 ± 0.53 | |
| pbmif-ko1 infections: 18.38 ± 0.19 | |||
| Minimum red blood cell density | F(1,8) = 0.20; P = 0.668 | Wild type infections: 8.00 ± 0.29 | |
| pbmif-ko1 infections: 8.29 ± 0.22 | |||
| Cumulative reticulocyte density | F(1,8) = 44.0; P< 0.001 | Wild-type-infected hosts had significantly fewer reticulocytes (0.18 ± 0.02) than pbmif-ko1-infected hosts (0.79 ± 0.10) | |
| Peak reticulocytemia | F(1,8)= 48.6; P< 0.001 | Wild-type-infected hosts had significantly lower peak reticulocytemia (1.02 ± 0.07) than pbmif-ko1-infected hosts (3.32 ± 0.45) | |
| C57BL/6 | Cumulative parasite density | F(1,7) = 2.63; P = 0.149 | Wild type infections: 2.14 ± 0.22 |
| pbmif-ko1 infections: 1.72 ± 0.15 | |||
| Peak parasitemia | F(1,7) = 3.86; P = 0.091 | Wild type infections: 14.83 ± 1.78 | |
| pbmif-ko1 infections: 11.18 ± 1.02 | |||
| Minimum mass | F(1,7) = 2.75; P = 0.142 | Wild type infections: 17.07 ± 0.44 | |
| pbmif-ko1 infections: 18.56 ± 0.71 | |||
| Minimum red blood cell density | F(1,7) = 1.26; P = 0.299 | Wild type infections: 6.93 ± 0.46 | |
| pbmif-ko1 infections: 7.58 ± 0.37 | |||
| Cumulative reticulocyte density | F(1,7)= 8.74; P = 0.021 | Wild-type-infected hosts had significantly fewer reticulocytes (1.31 ± 0.14) than pbmif-ko1-infected hosts (1.90 ± 0.15) | |
| Peak reticulocytemia | F(1,7)= 5.57; P = 0.0503 | There was a borderline trend for the peak reticulocytemia of wild-type-infected hosts (10.4 ± 0.84) to be marginally higher than the peak reticulocytemia of pbmif-ko1-infected hosts (8.12 ± 0.63). However, the mean reticulocytemia was higher in pbmif-ko1-infected hosts on 3 of the 4 days examined. Therefore, this trend does not contradict the reticulocyte density results. |
Results of experiment 1, in which BALB/c hosts and C57BL/6 hosts were infected with either wild-type or pbmif-ko1 parasites. The statistics are from general linear models, and the F ratio represents the variance attributable to each explanatory variable when the variance remaining unexplained by the model was compared. This ratio was weighted by the degrees of freedom associated with each explanatory variable and compared to the appropriate F distribution to generate the P value. For all variables, means and standard errors are shown. Variables for which wild-type infections differed significantly from pbmif-ko infections are indicated by boldface, and further explanation is provided. The units are percentages for proportion data and 109 cells/ml for density data.