Pathotyping of Australian isolates of Marek's disease virus in commercial broiler chickens vaccinated with herpesvirus of turkeys (HVT) or bivalent (HVT/SB1) vaccine and association with viral load in the spleen and feather dander

2013 ◽  
Vol 91 (8) ◽  
pp. 341-350 ◽  
Author(s):  
SW Walkden-Brown ◽  
A Islam ◽  
AFMF Islam ◽  
SK Burgess ◽  
PJ Groves ◽  
...  
Keyword(s):  
Viral Load ◽  
Disease Virus ◽  
Broiler Chickens ◽  
Marek's Disease Virus ◽  
Marek's Disease ◽  
Marek’S Disease Virus ◽  
Marek’S Disease ◽  
Herpesvirus Of Turkeys ◽  
Commercial Broiler

scholarly journals Quantitative profiling of the shedding rate of the three Marek's disease virus (MDV) serotypes reveals that challenge with virulent MDV markedly increases shedding of vaccinal viruses

2007 ◽  
Vol 88 (8) ◽  
pp. 2121-2128 ◽  
Author(s):  
Aminul Islam ◽  
Stephen W. Walkden-Brown
Keyword(s):  
Disease Virus ◽  
Broiler Chickens ◽  
Marek's Disease Virus ◽  
Marek's Disease ◽  
Marek’S Disease Virus ◽  
Marek’S Disease ◽  
Virus Serotype ◽  
Serotype 1 ◽  
Commercial Broiler ◽  
Virulent Virus

The shedding profile of Marek's disease virus serotype 1 (MDV1, virulent), serotype 2 (MDV2, vaccinal) and herpesvirus of turkeys (HVT, vaccinal) in commercial broiler chickens was determined by measuring the daily rate of production of feather dander from chickens housed in isolators and by quantifying the viral load of each of these serotypes in the dander using quantitative real-time PCR (qPCR). MDV1 and HVT viruses were detectable in dander filtered from isolator exhaust air from day 7 and MDV2 from day 12 after infection and thereafter until the end of the experiment at 61 days of age of the chickens. There was no difference in shedding rate among the three MDV1 isolates. Daily shedding of MDV1 increased sharply between days 7 and 28 and stabilized thereafter at about 109 virus copies per chicken per day, irrespective of vaccination status. Challenge with the three different MDV1 isolates markedly increased shedding of the vaccinal viruses HVT and MDV2 in dander by 38- and 75-fold, respectively. These results demonstrate the utility of qPCR for the differentiation and quantification of different MDV serotypes in feather dander and have significant implications for the routine monitoring of Marek's disease using qPCR assays of dust, for epidemiological modelling of the behaviour and spread of MDVs in chicken populations and for studies into the evolution of virulence in MDV1 in the face of blanket vaccination with imperfect vaccines that ameliorate disease but do not prevent infection and replication of virulent virus.

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