Strains of infectious bronchitis virus on the Delmarva peninsula and in Arkansas.

The constant-virus variable-serum neutralization test in chicken tracheal cultures was used to serotype infectious bronchitis virus (IBV) isolants from the Delmarva peninsula and Arkansas. Of 106 isolants obtained from Delmarva in 1971-1974, 93 were found to be the JMK strain, 5 Massachusetts (Mass), 5 Connecticut (Conn), 2 a new strain designated Maryland (Md) 27, and 1 a new strain designated Md 31. Of 26 isolants obtained from Arkansas between October, 1971, and February, 1973, 17 were Arkansas (Ark) 99, 4 Mass, 1 Conn, and 1 an additional new strain, designated Ark 155. Antisera produced against 2 more isolants each neutralized both Ark 99 and Mass viruses. Antiserum against another isolant neutralized both Ark 155 and Conn viruses. The neutralizing characteristics of the new strains are described.