Etiologic Relationship of the RI-67 Agent to “Acute Respiratory Disease (ARD)”1

Abstract

Sera obtained from donors of infected respiratory secretions and recipients of these secretions during a human transmission experiment carried out by the Commission on Acute Respiratory Diseases, 1945, were employed for neutralization titrations with the RI-67 agent isolated by Hilleman and Werner (6) and the A.D. agents obtained by Rowe and his co-workers (5). These studies indicated that the acute upper respiratory infection (ARD) was caused by an agent, presumably a virus, identical with or closely related to the RI-67 agent; that the A.D. agents did not produce this illness; and that ARD is a clinical entity distinct from the common cold or primary atypical pneumonia. In addition to the RI-67 agent, ARD is probably caused by other agents, immunologically different from the RI-67 virus. It is proposed that the RI-67 agent be called an ARD virus.