Effect of Large Doses of Streptomycin and Influenza Viruses on Chick Embryos

Search for an effective therapeutic agent against viral infections has been stimulated by the success attained in treating bacterial diseases with sulfonamides and antibiotics. However, since the problem is complicated by the intracellular growth of viruses, it is perhaps not remarkable that the results up to the present time have been almost consistently negative. 1 Recently a small quantity of streptomycin 2 ,∗ became available to us. Because of the effectiveness of this agent against a number of bacteria which have been resistant to previously studied antibiotics and chemo-therapeutic drugs, and its low toxicity for the chick embryo, 3 a laboratory trial against viruses which would grow in the chick embryo seemed warranted.

Method of Study. The allantoic cavities of 11- to 13-day-old embryonated chicken eggs were inoculated with various strains of influenza combined with varying amounts of streptomycin. The PR-8 and Olsen strains were used as representative of Type A and the Lee strain as an example of Type B influenza.† Each embryo received an original total inoculum of 0.15 cc; fo this 0.05 cc was a 1:1000 dilution of infected allantoic fluid, and 0.10 cc was either saline or the antibiotic reconstituted and diluted with sufficient saline to give the desired concentration. The virus and streptomycin were mixed immediately before inoculation. In those instances where more than one “dose” of streptomycin was given, the subsequent injections were made in 0.15 cc quantities within the first 24 hours. In the interim, the shellholes were sealed with a small tent of Scotch tape. The eggs were incubated at 36° to 37°C for 48 hours. After this period the allantoic fluids were collected and their hemagglutinating titers for chicken red cells were determined. 4