Marek΄s disease: rapid progress in research with unclear biological implementations.

Here we would like to provide a brief overview of the modern history of Marek΄s disease (MD) research with a focus on the most recent developments in experimental work and we will try to sum up their impact on the understanding of the biological properties of Marek΄s disease type 1 (MDV-1), the only representative of the Mardivirus genus causing fatal lymphoproliferative disease in poultry. We will also compare MDV-1 with other serologically-related poultry herpesviruses, Marek΄s disease virus type 2 (MDV-2) and herpesvirus of turkeys (HVT). Although MD was first described at the beginning of the last century, proper characterization of its biological impact on poultry production and utilization of molecular biology methods for detailed characterization of causative agent MDV-1 were introduced only in recent decades. However, many characteristics of MD infection, pathogenesis and vaccine protection mechanisms remain unclarified, though novel methods bring a challenge for better understanding of these unanswered questions.