[Etiological study of the fatal cases in the period of the influenza A epidemic of 1977-1978].

The etiology of the disease, the age structure of fatalities, the time of death were studied in 34 fatal cases in the period of influenza A (H1N1) epidemic in December 1977-February 1978 and in 33 fatal cases during influenza A/Victoria/3/75 (H3N2) epidemic in January-March, 1975 (data from some autopsy offices of Kiev). The results of the investigation of the etiology by immunofluorescence and the histological methods were mostly similar. The polyetiological structure of the diseases in the influenza epidemic of 1975 and rather monoetiological one in the influenza epidemic of 1977-1978 were observed. In 1975, fatal cases were found mostly in 2 age groups: infants under 1 year and adults over 20, in 1977-1978 in 4 age groups: infants under 1, children of 1-3, over 9, and adults. In both epidemics the maximum number of fatal cases coincided with the beginning of a decline in the epidemic wave and subsequently they were registered evenly for over one month. A high infection rate with a new influenza A virus variant (H1N1) was found among normal subjects in all age groups.