Document Detail

Avian infectious bronchitis and deep pectoral myopathy--A case control study.
MedLine Citation:
PMID:  23155012     Owner:  NLM     Status:  In-Data-Review    
Infectious bronchitis is caused by a coronavirus, infectious bronchitis virus (IBV). Infectious bronchitis is an acute and highly contagious disease of economic importance due to the reduction in weight gain observed with infected broilers and the drop in egg quality and production associated with infected laying hens. The presence of deep pectoral myopathy has been associated with IBV variants. This lesion is detected at slaughterhouses and is characterized by paleness and atrophy of the deep pectoral muscle, including necrosis of the region, leading to condemnations of the breast muscle, a valuable meat cut in the market. This work aimed to study the relationship between deep pectoral myopathy and IBV by describing tracheal and muscle lesions and comparing the frequency of IBV detection via reverse-transcription (RT) PCR in muscle, tracheal, and cecal tonsil samples from broilers with and without myopathy. A case-control study was conducted in 40 broiler flocks vaccinated with the Massachusetts strain. The case group consisted of 23 flocks that presented myopathic lesions under sanitary inspection and a control group of 17 flocks without myopathic lesions. The tracheal, cecal tonsil, and supracoracoid muscle (with and without lesions) samples from the 40 broiler flocks were screened by RT-PCR to detect IBV. Histopathology of muscle and tracheal tissue was carried out. Upon microscopic examination, the muscle samples from the case group presented extensive necrosis, intense mononuclear inflammatory infiltration, muscle fiber fragmentation, and fibrotic tissue, confirming myopathy, whereas muscles from the control group showed no alterations. The tracheal samples presented a large number of infiltrated mononuclear inflammatory cells that in some areas formed submucosal nodules. A total of 25 flocks tested IBV positive by RT-PCR: 14 from the case group and 11 from the control group. The IBV was detected by RT-PCR directly in muscle samples. Despite that, the relationship between deep pectoral myopathy and IBV was not established. The higher positive IBV RT-PCR percentage noted in the cecal tonsil samples demonstrates how important the choice of organs is for diagnostic purposes.
D O Almeida; R Tortelly; E R Nascimento; M A Chagas; M I Khan; V L A Pereira
Publication Detail:
Type:  Journal Article    
Journal Detail:
Title:  Poultry science     Volume:  91     ISSN:  0032-5791     ISO Abbreviation:  Poult. Sci.     Publication Date:  2012 Dec 
Date Detail:
Created Date:  2012-11-16     Completed Date:  -     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  0401150     Medline TA:  Poult Sci     Country:  United States    
Other Details:
Languages:  eng     Pagination:  3052-6     Citation Subset:  IM    
Department of Public Health and Veterinary Collective Health.
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