in that they do not encode the essential pathogenic factor nonstructural protein 1 ( nsp1 )
and instead start with nsp2 .
Avian infectious bronchitis virus ( IBV ) is a member of the group III coronaviruses , which differ from the other groups of coronaviruses in that they do not encode the essential pathogenic factor nonstructural protein 1 ( nsp1 ) and instead start with nsp2 .
Avian infectious bronchitis virus ( IBV ) is a member of the group III coronaviruses , which differ from the other groups of coronaviruses in that they do not encode the essential pathogenic factor nonstructural protein 1 ( nsp1 ) and instead start with nsp2 .