Congenital Heart Disease and Other Malformations Produced by Influenza A Virus and Allantoic Fluid in the Chick Embryo

Abstract

The effect of both active and heat-inactivated influenza A virus, chick allantoic fluid, and of buffered saline solution on the mortality and appearance of congenital malformations in the white Leghorn chick embryo, especially in the heart, was studied. Active influenza A virus produced a high mortality rate during the initial stages of development, when formation of the cardiac septa had barely begun and the primordia of the valves were yet to appear. Consequently, no congenital heart disease was found in the group inoculated with active virus, though profound alterations of the nervous system, sensorial organs and general body shape were observed. The effects of allantoic fluid with and without heat-inactivated virus were the same high incidence of congenital valvular disease (pulmonary stenosis, thickening of the mitral valve), and interventricular septal defect. Inoculation of buffered saline solution produced an increased mortality rate and structural malformations outside the heart, but had no effect on the development of the heart. Possible mechanisms of action of these terato-genic agents are discussed.