Expression of chicken interleukin-2 by a highly virulent strain of Newcastle disease virus leads to decreased systemic viral load but does not significantly affect mortality in chickens

Leonardo Susta; Diego G. Diel; Sean Courtney; Stivalis Cardenas-Garcia; Roy S. Sundick; Patti J. Miller; Corrie C. Brown; Claudio L. Afonso

doi:10.1186/s12985-015-0353-x

Virology Journal

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

From: Expression of chicken interleukin-2 by a highly virulent strain of Newcastle disease virus leads to decreased systemic viral load but does not significantly affect mortality in chickens

Recombinant virus	Clinical signs	Lesions
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.

Numbers indicate the fraction of birds presenting a certain clinical sign or lesion over the number of birds remaining in the cage (clinical signs), or the number of birds necropsied that day (lesions)

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