Mosquito pool suspensions were inoculated in parallel into embryonated hens' eggs, mice, chick embryo tissue cultures and hamster kidney tissue cultures for a comparison of the sensitivity of these four host systems for the isolation of St. Louis encephalitis, Western equine encephalomyelitis and Turlock viruses. Mice and hamster kidney tissue cultures were the most sensitive hosts for the recovery of SLE virus, and approximately the same number of isolates were recovered in each of these systems. Embryonated eggs were slightly more sensitive than the other three host systems for the isolation of WEE virus. The only satisfactory host system for the isolation of Turlock virus from the mosquito pools tested was the embryonated egg.
The facility of identification of the isolates in the different host systems is discussed.