Forms and Mechanisms of Influenza a Virus Circulation in the Body

This article describes the results of many years of systematic investigation, by the author and coworkers, into influenza A virus circulation within the host body and its population. It has been established that the agent may occur in the body in three principal forms: namely, a free-circulating form, an infectious complex, and an immune complex. The complexes arise when influenza virions combine with specific immunoglobulin molecules and as a result the virus still circulates at later stages of infection (1 to 6 months). A free-circulating form is recognized primarily in the acute phase of influenza (7 to 10 days). Evidence is cited that some components of influenza viruses (M, NS and other proteins) change during their continuing survival in the body and the related role of defective-interfering (DI) virus particles is discussed.