Table 3.
Risk of fecal oocyst shedding, diarrhea, and fecal oocyst shedding with diarrhea in calves experimentally challenged with C. parvum oocystsa.
| Dose of C. parvum oocysts | Log dose of C. parvum oocysts | No. calves challenged | Fecal shedding (%) | Diarrhea (%) | Fecal shedding + diarrhea (%) |
|---|---|---|---|---|---|
| 0 | 0 | 3 | 0 (0) | 0 (0) | 0 (0) |
| 25 | 1.4 | 5 | 3 (60) | 3 (60) | 2 (40) |
| 50 | 1.7 | 4 | 4 (100) | 3 (75) | 3 (75) |
| 100 | 2 | 3 | 3 (100) | 3 (100) | 3 (100) |
| 500 | 2.7 | 3 | 3 (100) | 3 (100) | 3 (100) |
| 1000 | 3 | 3 | 3 (100) | 3 (100) | 3 (100) |
| 10,000 | 4 | 3 | 3 (100) | 3 (100) | 3 (100) |
| 100,000 | 5 | 3 | 3 (100) | 3 (100) | 3 (100) |
| 1,000,000 | 6 | 3 | 3 (100) | 3 (100) | 3 (100) |
a
Linear regression analysis of the data yielded an ID50 of 5.8 oocysts for fecal oocyst shedding, 9.7 oocysts for diarrhea, and 16.6 oocysts for fecal oocyst shedding with diarrhea.