Table 3. Cumulative mortality after NNV challenge with 60 days of observation.

Group	Cumulative mortality rate (%)
1	93.3
2	60a)
3	73.3b)
4	60a)
5	53.3c)

Two-sided P-values over group 1 were a) 0.0810, b) 0.3295 and c) 0.0352 based on Fisher’s exact test.