TABLE 2.
Anti-Cryptosporidium fIgA and outcome parametersa
| Category | n | Median change in fIgA RI | Quartiles (Q1, Q3) | P |
|---|---|---|---|---|
| Challenge dose | ||||
| >1,000* | 5 | 5.57 | 4.24, 7.81 | 0.027 |
| 300–500* | 9 | 1.68 | 0.75, 20.62 | 0.039 |
| 30–100 | 12 | 0.15 | −0.03, 0.50 | |
| Clinical group | ||||
| Oocyst positive | ||||
| With diarrhea** | 12 | 4.24 | 1.35, 27.92 | 0.022 |
| Without diarrhea** | 4 | 0.82 | 0.34, 4.48 | 0.257 |
| Oocyst negative | ||||
| With diarrhea** | 3 | 0.07 | −0.38, 0.22 | 0.909 |
| No symptoms | 7 | 0.02 | −0.05, 6.71 | |
| Oocyst shedding | ||||
| Yes | 16 | 2.78 | 0.68, 7.96 | 0.003 |
| No | 10 | 0.03 | −0.05, 1.85 | |
| Infection | ||||
| Presumed infected | 19 | 1.68 | 0.43, 7.50 | 0.060 |
| Presumed uninfected | 7 | 0.02 | −0.05, 6.71 | |
| Diarrhea | ||||
| Yes | 15 | 2.41 | 0.50, 8.11 | 0.065 |
| No | 11 | 0.30 | −0.004, 5.56 |
a
fIgA is expressed as the median change in the RI. The RIs for each volunteer were calculated as the ratio of the net absorbance divided by the total fIgA concentration. Postchallenge indices used for comparisons in the table represent the RI of the peak postchallenge absorbance value for each volunteer.
b
Statistical significance determined by Kruskal-Wallis test. *, compared to the 30–100 challenge dose group. **, compared to the oocyst negative, no symptoms group.