FIG 1.

Survival rates within six groups of SPF chickens following intratracheal inoculation with either low (10³ PFU) or high (10⁴ PFU) doses of CSW-1 or V1-99 ILTV or coinoculation with the two viruses at the same doses. All birds inoculated only with CSW-1 survived. The group inoculated with a low dose of only V1-99 (group 5) had an 80% survival rate at day 4 and then a survival rate of 60% at days 6 and 8. Meanwhile, in the group inoculated with a high dose of V1-99 (group 6), a survival rate of 45% was seen at day 4, and the survival rate was 40% at days 6 and 8. Group 1 (birds coinoculated with a low dose of both viruses) had a survival rate similar to that of the group that received the single high dose of V1-99. None of the birds in group 2 (coinoculated with a high dose of both viruses) survived beyond day 4.