infectious bronchitis virus (ibv) is an acute and contagious viral disease of poultry that affects different systems, including the respiratory tract in particular. ibv causes major economic losses in the poultry industry globally. due to antigenic variation of the causative agent, control of the disease is difficult. to control the disease, many vaccines that belong to different serotypes are ...

abstract the pvyntn strain induces potato tuber necrotic ringspot disease ptnrd . pvyntn strain is sub group of tobacco necrosis veinal pvyn strain . pvyntn strain is a recombinant between pvyn and pvyo strains . symptoms are often totally symptomless or undetectable by visual inspections at harvest , usually are apparent during post harvest in storage conditions and induce to decrease quality ...