Marek's disease (MD) is one of the most common lymphoproliferative diseases of chickens which causes mononuclear infiltration of different tissues and organs, such as peripheral nerves, gonad, viscera, muscle and skin. It is caused by an Alphaherpesvirus, called MDV or Gallid Herpesvirus 2 (GaHV-2). Although it has been studied in all its aspects from the early ‘60s and vaccines are now used all over the world, many issues remain unresolved due to the complexity of the disease. In order to activate specific surveys in the field, the IZSVe has developed a series of molecular diagnostic methods for the MD. The development of these tests makes a rapid and robust diagnosis possible, allowing to distinguish the vaccine strains from those pathogens and to identify the pathotype in a short time. Samples from backyard farms, samples (environmental dust, feathers, spleens and livers) taken from an industrial flock of breeders in the first months of life, as well as samples from clinical cases of particular interest were analysed for validation of the methods. The data obtained so far confirm the high presence of Marek's disease in rural farms. The low number of outbreaks in industrial flocks lead us to believe that currently used chicken genetic lines and the vaccinations adopted are in most cases appropriate to counter the circulating viruses, which have mostly a medium-low pathogenic power. The detection of pathogenic viruses in the environment, even in farms with high standards of biosecurity which undergo intensive cleaning and disinfection cycles, highlights the importance of proper vaccination practices.
SVILUPPO E APPLICAZIONE DI TEST DIAGNOSTICI MOLECOLARI PER L’IDENTIFICAZIONE E LA CARATTERIZZAZIONE DEI VIRUS DELLA MALATTIA DI MAREK CIRCOLANTI IN ITALIA
Piccirillo A.;
2016
Abstract
Marek's disease (MD) is one of the most common lymphoproliferative diseases of chickens which causes mononuclear infiltration of different tissues and organs, such as peripheral nerves, gonad, viscera, muscle and skin. It is caused by an Alphaherpesvirus, called MDV or Gallid Herpesvirus 2 (GaHV-2). Although it has been studied in all its aspects from the early ‘60s and vaccines are now used all over the world, many issues remain unresolved due to the complexity of the disease. In order to activate specific surveys in the field, the IZSVe has developed a series of molecular diagnostic methods for the MD. The development of these tests makes a rapid and robust diagnosis possible, allowing to distinguish the vaccine strains from those pathogens and to identify the pathotype in a short time. Samples from backyard farms, samples (environmental dust, feathers, spleens and livers) taken from an industrial flock of breeders in the first months of life, as well as samples from clinical cases of particular interest were analysed for validation of the methods. The data obtained so far confirm the high presence of Marek's disease in rural farms. The low number of outbreaks in industrial flocks lead us to believe that currently used chicken genetic lines and the vaccinations adopted are in most cases appropriate to counter the circulating viruses, which have mostly a medium-low pathogenic power. The detection of pathogenic viruses in the environment, even in farms with high standards of biosecurity which undergo intensive cleaning and disinfection cycles, highlights the importance of proper vaccination practices.Pubblicazioni consigliate
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