Caratterizzazione molecolare di un ceppo mild del virus della malattia di Marek evidenziato in polli rurali con forma nervosa

Marek’s disease is an important lymphoproliferative disease of chickens caused by Gallid herpesvirus 2, which is commonly referred to as Marek’s disease virus serotype 1 (MDV-1). This virus induces a range of pathological conditions including central and peripheral nervous system signs and, most frequently, visceral lymphomas. There are very few data on the molecular characteristics and epidemiology of MDV-1 in Italy, both in commercial and in backyard chickens. For that reason feathers and organs were collected from Cochin chickens from a rural context affected by a Marek’s disease classical nervous form. The MDV-1 strain detected by PCRs was sequenced and compared to a MDV-1 strain detected from broilers breeders affected by visceral lymphomas. The number of PPPP motif repetitions found in the transactivation domain of the Meq protein, indicated that the virus detected in Cochin chickens was mild MDV-1, while the one detected in commercial poultry was very virulent or very virulent plus MDV-1. Clinical, macroscopic and microscopic fi ndings supported the molecular results.