Table 1 Summary of clinical signs and lesions in 4-week-old chickens infected with rZJ1-GFP, rZJ1-IL2, and BHI

rZJ1-GFP

Day 1 pi: no signs

Day 2 pi: splenomegaly (3/3); petechial hemorrhages in thymus (2/3).

Day 2 pi: no signs

Day 3 pi: conjunctivitis (2/3); mottled and enlarged spleen (3/3).

Day 3: mild conjunctivitis

Day 4 pi: conjunctivitis (1/3); thymic atrophy (2/3); enlarged mottled spleen (2/3); petechial hemorrhages diffuse in the intestine (3/3); necrosis in cecal tonsils (2/3); hemorrhages in proventriculus (1/3); bursal atrophy (1/3); severely dehydrated (1/3).

Day 4 pi: moderate conjunctivitis and depression (3/10 had severe depression)

Day 5 pi: enlarged mottled spleen (3/3); hemorrhages in: duodenal loop, cecal tonsils, and throughout intestine (3/3); thymic atrophy (3/3); petechial hemorrhages in proventriculus (1/3).

Day 5 pi: severe conjunctivitis, severe depression: 3/5 were unable to stand; 1/5 had neurological signs and depression, 1/5 died overnight. All birds were euthanized in extremis.

rZJ1-IL2

Day 1 pi: no signs

Day 2 pi: conjunctivitis (2/3); splenomegaly (3/3); hemorrhages in: cecal tonsils (2/3), bursa (1/3), and thymus (1/3).

Day 2 pi: moderate conjunctivitis

Day 3 pi: conjunctivitis (3/3); mottled and enlarged spleen (3/3); diarrhea (1/3).

Day 3 pi: moderate conjunctivitis and mild depression

Day 4 pi: severe bilateral conjunctivitis (3/3); enlarged and mottled spleen (3/3); necrosis in cecal tonsils (2/3); mild thymic atrophy (1/3).

Day 4 pi: moderate to severe conjunctivitis, depression, and one animal (1/10) with neurological signs (unable to stand with head twitch)

Day 5 pi: conjunctivitis (2/3); bursal atrophy (3/3); thymic atrophy (1/3); enlarged and mottled spleen (1/3); mild hemorrhages in duodenal loop (1/3); cecal tonsils necrosis (1/3); severe dehydration (2/3).

Day 5 pi: bilateral moderate to severe conjunctivitis, depression

BHI

No lesions or clinical signs observed.