Characterization by restriction fragment length polymorphism and sequence analysis of field and vaccine strains of infectious laryngotracheitis virus involved in severe outbreaks
- 10 December 2010
- journal article
- research article
- Published by Taylor & Francis Ltd in Avian Pathology
- Vol. 39 (6), 425-433
- https://doi.org/10.1080/03079457.2010.516386
Abstract
At the end of 2002 and throughout 2003, there was a severe outbreak of infectious laryngotracheitis (ILT) in an intensive production area of commercial hens in the Sao Paulo State of Brazil. ILT virus was isolated from 28 flocks, and 21 isolates were genotyped by polymerase chain reaction and restriction fragment length polymorphism (PCR-RFLP) using four genes and eight restriction enzymes, and by partial sequencing of the infected cell protein 4 (ICP4) and thymidine kinase (TK) genes. Three groups resulted from the combinations of PCR-RFLP patterns: 19 field isolates formed Group I, and the remaining two isolates together with the chicken embryo origin (CEO) vaccine strains formed Group II. Group III comprised the tissue-culture origin (TCO) vaccine strain by itself. The PCR-RFLP results agreed with the sequencing results of two ICP4 gene fragments. The ICP4 gene sequence analysis showed that the 19 field isolates classified into Group I by RFLP-PCR were identical among themselves, but were different to the TCO and CEO vaccines. The two Group II isolates could not be distinguished from one of the CEO vaccines. The nucleotide and amino acid sequence analyses discriminated between the Brazilian and non-Brazilian isolates, as well as between the TCO and CEO vaccines. Sequence analysis of the TK gene enabled classification of the field isolates (Group I) as virulent and non-vaccine. This work shows that the severe ILT outbreak was caused by a highly virulent, non-vaccine strain.This publication has 27 references indexed in Scilit:
- Differentiation of field isolates and vaccine strains of infectious laryngotracheitis virus by DNA sequencingVaccine, 2009
- Reverse restriction fragment length polymorphism (RRFLP): A novel technique for genotyping infectious laryngotracheitis virus (ILTV) live attenuated vaccinesJournal of Virological Methods, 2009
- Development and validation of nested-PCR for the diagnosis of clinical and subclinical infectious laryngotracheitisJournal of Virological Methods, 2008
- Survey of infectious laryngotracheitis outbreak in layer hens and differential diagnosis with other respiratory pathogensBrazilian Journal of Poultry Science, 2007
- Development and validation of a real-time Taqman® PCR assay for the detection and quantitation of infectious laryngotracheitis virus in poultryJournal of Virological Methods, 2007
- Rapid detection and characterization from field cases of infectious laryngotracheitis virus by real-time polymerase chain reaction and restriction fragment length polymorphismAvian Pathology, 2006
- Evaluation of the Efficacy of a Live Fowlpox-Vectored Infectious Laryngotracheitis/Avian Encephalomyelitis Vaccine Against ILT Viral ChallengeAvian Diseases, 2006
- Characterization of infectious laryngotracheitis virus isolates: demonstration of viral subpopulations within vaccine preparations.Avian Diseases, 2001
- Rapid differentiation of vaccine strains and field isolates of infectious laryngotracheitis virus by restriction fragment length polymorphism of PCR productsJournal of Virological Methods, 1997
- Studies on a Tissue-Culture-Modified Infectious Laryngotracheitis VirusAvian Diseases, 1964