THE SURVIVAL OF POLIOMYELITIS AND COXSACKIE VIRUSES FOLLOWING THEIR INGESTION BY FLIES

Poliomyelitis virus and Coxsackie (or C) virus were quantitatively fed to blowflies, Phormia regina and Phaenicia sericata, and to houseflies, Musca domestica. Naturally infectious human stools were the source of virus. Poliomyelitis virus can be almost quantitatively recovered from flies and from their excreta collected over a period of several days following the feeding. C virus can also be recovered but in lesser yields. No conclusive evidence for virus multiplication in these laboratory-bred insects was obtained. Poliomyelitis virus from human sources could be detected in flies between the 5th and 17th day and in the excreta between the 4th and 10th day. Murine-adapted strains of poliomyelitis virus and murine encephalomyelitis virus could not be detected beyond the 5th day, even though comparable amounts of virus were fed. The persistence of C virus excretion (2 to 12 days) varied directly with the amount of virus fed. Poliomyelitis virus, as present in human stools, survived drying and storage at room temperature for at least 3 days and at 4° for 3 weeks. C virus from human stools under the same circumstances was detected for 15 days at room temperature (with marked drop in titer after the 3rd day) and for 21 days at 4° with little loss in titer. When stool samples were fed to flies and the dried excreta of the insects examined, it was found that (a) poliomyelitis virus persisted for at least 1 to 2 days at room temperature and for 3 to 4 days at 4°, and (b) C virus persisted for 1 day at room temperature and for 5 days at 4°. Poliomyelitis virus could be carried through only two serial passages in adult flies. Flies emerging from maggots fed virus were free from the agent.