Nephropathogenic Infectious Bronchitis in Pennsylvania Chickens 1997–2000

Abstract

Nephropathogenic infectious bronchitis (NIB) was diagnosed in 28 infectious bronchitis virus (IBV)-vaccinated commercial chicken flocks in Pennsylvania from December 1997 to July 2000. Early dinical signs were increased flock mortality and urinary water loss (polyuria and pollakiuria) leading to wet litter. Daily mortality ranged from 0.01% in layers to 2.45% in broilers, with total broiler mortality as high as 23%. Severe renal swelling and accumulation of urates in the tubules were commonly seen. Visceral gout and urolithiasis were less frequently observed. Histopathologic changes included characteristic tubular epithelial degeneration and sloughing with lymphoplasmacytic interstitial nephritis. Minimal respiratory disease signs were noted in broilers. Egg production and shell quality declined in layers. Confirmatory diagnosis of NIB was made by IBV antigen-specific immunohistochemical staining of the renal tubular epithelium and virus isolation. Sequencing of the S1 subunit gene of 21 IBV isolates showed the NIB outbreak to be associated with two unique genotypes, PA/Wolgemuth/98 and PA/171/99. The cases from which the genotypes were isolated were clinically indistinguishable. The NIB viruses were unrelated to previously recognized endemic strains in Pennsylvania and were also dissimilar to each other. Genotype PA/Wolgemuth/98 was isolated almost exclusively during the first 14 mo of the outbreak, whereas PA/171/99 was recovered during the final 18 mo. The reason for the apparent replacement of PA/Wolgemuth/98 by PA/171/99 is not known.

Prevalence, Serodiagnosis and Histopathological Changes in Field Cases of Infectious Bronchitis in Chickens

“…The lesions in tubules are most prominent in medulla. In urolithiasis, the urates associated with atrophied kidneys are distended with urates and often contains large caliculi composed of mainly of urates (Janse et al, 1994;Ziegler et al, 2002).These result also made an agreements of present findings.…”

Infectious bronchitis virus S1 gene sequence comparison is a better predictor of challenge of immunity in chickens than serotyping by virus neutralization

“…The fifth strain, PA/Wolgemuth/98, is maintained as an allantoic fluid stock in our laboratory. PA/Wolgemuth/98 and PA/171/99 are nephropathogenic strains associated with an infectious bronchitis outbreak from 1998 to 2000 (Ziegler et al ., 2002).…”

Sequence analysis of S1 genes of infectious bronchitis virus isolated in Thailand during 2008–2009: identification of natural recombination in the field isolates

“…In hens, respiratory distress and a decrease in egg production have been reported [3]. Some strains of IBV can cause acute nephritis and urolithiasis associated with a high mortality of infected chickens [4,5]. In addition, IBV has also been reported to cause proventriculitis [6].…”