Infectious Laryngotracheitis (ILT) - Respiratory Herpes Virus of Poultry
Published:January 22, 2008
Summary
Infectious Laryngotracheitis (ILT) is usually considered to be a backyard flock problem. However, this disease continues to plague the poultry industry with sporadic episodes across the province of Ontario. Due to the persistent, latent, infectious nature of the virus, it can perpetuate itself, even after vaccination. Rolling reaction from chicken embryo origin (CEO) vaccines and transmission from...
I am a little confused that vaccination also makes the bird CARRIER, and the susceptible birds should not mix with them?
Does it mean we shouldn't practice the vaccination and be concentrated on biosecurity measures?
Tamil Nadu Veterinary and Animal Sciences University
2 de febrero de 2008
Dear Sir, A student Mr. Syedkaleemuhassan raised a question that, could the vaccinated birds act as a carrier or/not, and if do so should we not use the vaccination strategy or can. With regarding on this I would say that while preparing the vaccine some ingredients such as virus/bacteria that would be the source of antigen, adjuvant to enhance the immunity and to produce a depo at the site of vaccination, etc. are being added. This produced vaccines may be killed/live or attenuated, accordingly they are processed and become marketed for livestock purposes. While processing vaccination the virulent factors that could cause disease and so to produce death is inactivated/killed by any means that defines only the antigenic nature of the organism would be retained by eliminating all other determinants that are responsible to produce disease. In this case, if the vaccine is not prepared upto the level of standard or inactivation or attenuation is not done accurately. the vaccine may carry the disease producting property and so, there is no doubt that vaccinated birds would act as a carrier and it is implied. Moreover, the virus/bacteria should not have any mutating property in itself and this wouldl also can modify the antigenic property and may cause the disease.
Well, ILT is a herpesvirus and latency is the characterisic feature of this virus. Among recovered birds and even birds vaccinated with a live vaccine, the ILTV can become latent and the birds become carriers. Thus birds which appear healthy may excreate the virus intermittently (reactivation) for long periods. Because vaccination can result in latently infected carrier birds, it is recommended for use only in geograpic areas where the disease is endemic.
M.R. Reddy, PhD, MACVS
Senior scientist
Project Directorate on Poultry
Hyderabad-500 030
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