Figure 3.

Kaplan-Meier survival curves for groups that were exposed to serotype 2 only (marked by Δ), to serotype 9 only (marked by x), or to both serotypes (marked by □). Survival analysis showed that the hazard for mortality in pigs exposed to both serotypes was 6.59 times (95% C.I.: 1.41–30.86) increased compared to exposure to serotype 9 only, and 6.31 times (95% C.I.: 2.01–19.77) reduced compared to exposure to serotype 2 only. The hazard ratios did not differ significantly between inoculated and contact pigs.