Marek’s disease virus (MDV) infects poultry. It is a member of the Herpesviridae family, in the genus Mardivirus and it can be divided into pathotypes that are dependent on virulence: mild (m), virulent (v), very virulent (vv), and very virulent plus (vv+). MDV is enveloped, with a capsid and a double stranded DNA genome.
Associated diseases:
MDV causes Marek's disease which causes huge losses in the poultry industry.
Clinical signs:
- Paralysis of the legs and wings
- Enlargement of peripheral nerves
- Tumours affecting organs such as the heart, liver, spleen, lungs, ovaries and skin
- Immunosuppression
- Brain oedema (swelling)
- Acute rash
Disease transmission:
MDV is a very infectious airborne pathogen which is transmitted via inhalation. Infected feather follicles can act as a reservoir even after they have been shed.
Disease prevalence:
Marek’s disease has been present in most industrialised countries.
Impact for Society – what are we doing?
Marek’s disease annual cost to the industry is estimated to be in the range of US $1-2 billion. The Pirbright Institute is researching a number of different aspects of the disease including determining how it induces tumours, the reason behind its steadily increasing virulence and studying the molecular and cellular mechanisms of the immune responses against MD infections. This information will be valuable in the development of more effective vaccine formulations or vaccination strategies.
