Improving control of infectious laryngotracheitis in Australian broiler flocks


This project aims to use cutting-edge molecular technology to improve control of ILTV in Australian broiler flocks. In particular this project will investigate Australian ILTV strains in order to develop a sensitive and rapid ILTV detection and classification system, and to understand the epidemiology of current disease outbreaks. Specific outcomes from this project will include: 1) Identification of the origin(s) of the ILTV strains involved in recent disease outbreaks, their relationships to other ILTV strains (including vaccine strains) and the molecular features that contribute to viral pathogenicity. This information will allow actions to be taken to prevent or minimise emergence and spread of ILTV field stains from these sources and will also provide valuable fundamental information about ILTV pathogenicity. 2) A new diagnostic tool for the rapid detection and classification of ILTV using real-time PCR and high resolution melt curve (qPCR-HRM) analysis. This diagnostic system will provide producers with information regarding ILTV strain virulence and relatedness to other strains and will thus allow producers to make informed management decisions regarding ILT control. The rapidity of this system will allow ‘real time” tracking of disease during outbreaks and improve our understanding of ILT epidemiology so that timely and effective control measures can be implemented. 3) Identification of any ILTV field strains that can overcome the vaccine-induced immunity elicited by standard vaccination protocols, as well as the development of optimised vaccination protocols to enhance control of these strains. This addresses the hypothesis that there may be Australian field strains of ILTV that are capable of causing disease in vaccinated birds. The development of more effective vaccination strategies to control these strains will directly enhance control of ILTV and will allow vaccine resources to be used more efficiently.


Chicken Meat

Research Organisation

The University of Melbourne

Objective Summary

The overall objective of this project is to improve control of infectious laryngotracheitis virus (ILTV) in Australian broiler flocks. Specific R&D objectives include 1) To use high-throughput, next-generation DNA sequencing, as well as gene-expression analysis of the entire ILTV genome, to comprehensively characterise the virus strains causing outbreaks, and to investigate their genotypic relationships with other strains (including vaccine strains). The source of strains involved in recent ILTV outbreaks will be determined by these analyses. 2) To use the above results to establish a sensitive and rapid qPCR-HRM diagnostic analysis system for the detection and differentiation of ILTV vaccine and field strains. This system would be based on variable genomic regions and genomic regions associated with viral virulence. 3) To determine in any Australian field isolates of ILTV are resistant to the vaccine-induced immunity elicited by standard vaccination protocols and to develop a more effective vaccination program to control disease caused by these isolates.

Project Code


Project Stage


Project Start Date

Friday, May 22, 2009

Project Completion Date

Saturday, September 15, 2012

National Priority

Safeguarding Australia

National Priority

CME-Improve chicken meat production through the whole supply chain