TABLE 1.

Comparison of virulence parameters for infections with wild-type and pbmif-ko parasitesa

Host miceVariableTest statisticsFurther details
BALB/cCumulative parasite densityF(1,8) = 0.59; P = 0.464Wild type infections: 1.04 ± 0.15
pbmif-ko1 infections: 0.68 ± 0.16
Peak parasitemiaF(1,8) = 5.00; P = 0.056Wild type infections: 7.24 ± 1.03
pbmif-ko1 infections: 4.88 ± 1.20
Minimum massF(1,8) = 3.04; P = 0.119Wild type infections: 17.74 ± 0.53
pbmif-ko1 infections: 18.38 ± 0.19
Minimum red blood cell densityF(1,8) = 0.20; P = 0.668Wild type infections: 8.00 ± 0.29
pbmif-ko1 infections: 8.29 ± 0.22
Cumulative reticulocyte densityF(1,8) = 44.0; P < 0.001Wild-type-infected hosts had significantly fewer reticulocytes (0.18 ± 0.02) than pbmif-ko1-infected hosts (0.79 ± 0.10)
Peak reticulocytemiaF(1,8) = 48.6; P < 0.001Wild-type-infected hosts had significantly lower peak reticulocytemia (1.02 ± 0.07) than pbmif-ko1-infected hosts (3.32 ± 0.45)
C57BL/6Cumulative parasite densityF(1,7) = 2.63; P = 0.149Wild type infections: 2.14 ± 0.22
pbmif-ko1 infections: 1.72 ± 0.15
Peak parasitemiaF(1,7) = 3.86; P = 0.091Wild type infections: 14.83 ± 1.78
pbmif-ko1 infections: 11.18 ± 1.02
Minimum massF(1,7) = 2.75; P = 0.142Wild type infections: 17.07 ± 0.44
pbmif-ko1 infections: 18.56 ± 0.71
Minimum red blood cell densityF(1,7) = 1.26; P = 0.299Wild type infections: 6.93 ± 0.46
pbmif-ko1 infections: 7.58 ± 0.37
Cumulative reticulocyte densityF(1,7) = 8.74; P = 0.021Wild-type-infected hosts had significantly fewer reticulocytes (1.31 ± 0.14) than pbmif-ko1-infected hosts (1.90 ± 0.15)
Peak reticulocytemiaF(1,7) = 5.57; P = 0.0503There 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.
  • a 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.