Marek's disease is one of the most ubiquitous avian infections; it is identified in chicken flocks worldwide. In 1907, Marek Jozsef reported paresis / polyneuritis in roosters, a classical form of the disease and subsequently several outbreaks of acute form (Visceral form) of the disease among chickens had been reported across the world.

Marek's disease virus, a herpesvirus, causes Marek's disease. Three serotypes pf the cell-associated herpes viruses are recognized. Currently, virulent serotype 1 strains are further divided into pathotypes, which are often referred to as mild (m MDV), virulent (v MDV), very virulent (vv MDV), and very virulent plus (vv+ MDV) Marek's disease virus strains.

Transmission is primarily by air within the poultry house, in feather dander, chicken house dust, fecal matter and saliva. The disease is highly contagious and readily transmitted among chickens. The virus matures into a fully infective, enveloped form in the epithelium of the feather follicle, from which it is released into the environment. Once the virus is introduced into a chicken flock, regardless of vaccination status, infection spreads quickly from bird to bird. Infected chickens continue to be carriers for long periods and act as sources of virus.

Rearing of chicks in isolation away from older birds or production site has to be a major priority. Regularly the feathers and dander should be eliminated and cleaned / disposed properly. Vaccination is the central strategy for the prevention and control of Marek's disease. The most widely used vaccine consists of turkey herpesvirus. Attenuated serotype 1 Marek's disease vaccines are also available; of these, Rispens strains appear particularly effective.