Recovery of New Agent from Patients with Acute Respiratory Illness

A microbial agent, presumably a virus, was recovered from throat washings from a patient with primary atypical pneumonia in an epidemic of acute respiratory illness which occurred at Fort Leonard Wood during the winter of 1952-1953. This agent multiplies in human cell tissue cultures producing obvious cytopathogenic changes but not in common laboratory hosts. The patient whose throat washings yielded the virus de veloped specific neutralizing and complement-fixing antibodies for the agent. Other patients in the epidemic with primary atypical pneumonia (PAP) or undifferentiated acute respiratory disease (ARD) also developed antibodies for the agent but those cases with proved influenza A′ did not. A portion of the population maintains an antibody level against the new agent suggesting a rather general experience with it.