Studies of the fate of type 1 polioviruses in flies.

Studies on the fate of type 1 polioviruses in two common species of flies were carried out. The amount of virus in carcasses and excreta at different times was determined by the plaque assay method. Flies and their excreta remained infective for 11 days when kept at room temperature or when incubated at 36 degrees C. for 2 hours a day. Flies remained infective for 3 months when kept in hibernation. A relative increase in titer was found to occur between 9 and 18 hours after feeding if the flies were incubated at 36 degrees C. for 5 to 15 hours a day. The peak occurred later, at 40 to 52 hours after feeding if less incubation was used. Titers in excreta were parallel to titers in carcasses. A twofold increase in titer over the initial feeding was observed on 3 occasions with type 1 Mahoney but not with the LSc strain of virus.