Influenza virus C infection in England.

Abstract

In 1947 virus was isolated by Taylor (1949) from the throat washings of a man in New York who was suffer ing from a mild influenzal illness. It resembled the influenza viruses but differed from types A and B antigenically. Francis et al. (1950) later reported the recovery of a similar organism from the throat of a patient also suffering from an influenzal illness, and found serological evidence of infection in a number of other They suggested that the new virus be known as influenza virus Type C, and this designation has been generally accepted (Taylor, 1951 ; W.H.O., 1953). Isolations of influenza virus C have since been re ported from other laboratories in the United States (Gerber et al., 1952; DeMeio et al., 1955) and from Japan (Fukumi et al., 1951) and Czechoslovakia (Styk, 1954). However, few illnesses accompanied by an increase in antibody to this virus have been reported, and Minuse et al. (1954), commenting on experience at Ann Arbor, Michigan, stated that continued search has yielded only a few additional cases. Studies of the distribu tion of antibody to influenza virus C in American popu lation groups were made by Hilleman et al. (1953) and Davenport et al. (1953). These surveys showed a sharp rise in the general level of antibody during childhood, particularly in the earlier years. It seems probable that, in the United States, influenza virus C infection occurs widely in young children and may be accompanied by minor respiratory illness. Our own findings and those of Grist (1955) suggest that the same may be true in Britain. In the course of a number of investigations during the past three years we have had an opportunity to make clinical and laboratory observations on the presence of influenza virus C infection in this country. Histories of illness were studied in persons whose sera showed anti body changes, and sera from these investigations were used to estimate the age distribution of antibody in the population. Cases of influenza virus C infection were found during three investigations. In the winter of 1952-3, 455 factory workers who had volunteered for an influenza vaccine trial were under observation in Luton, Bedfordshire (McDonald and Andrews, 1955). Eighty two persons with an acute respiratory illness causing absence from work were visited at home. Specimens were-taken from 63 of them for laboratory examination, and serological evidence of virus C infection was found in one (Table-Case 1). In the following winter approxi mately 50 volunteers from each of five factories in widely separated parts of the country were bled at monthly intervals and their respiratory illnesses noted. Evidence of infection was found in one volunteer (Table -Case 2). In a study of 25 families in Wembley, Middlesex, between November, 1953, and April, 1955, a clinical record of all respiratory illnesses was kept, and blood taken from the adult members at approximately three-monthly intervals. Throat swabs or throat wash ings for virus isolation were obtained in all febrile illnesses, and in adults additional blood specimens were taken to provide paired sera for any such illness. Laboratory evidence indicated that influenza virus C infection occurred in eight persons during this study (Table-Cases 3 to 10).