An Evaluation of Various Tissues in Culture for Isolation of Eastern Equine Encephalitis Virus.∗

Summary and Conclusions An evaluation of embryonated hens' eggs, suckling mice and cultures of various tissues for the primary isolation of EEE virus from human, equine, avian and arthropod specimens indicated that suckling mice were the most effective. The evaluation was based on a comparison of the ID50s obtained by concurrently inoculating suckling mice intracerebrally and intraperitoneally, 9–12-day-old embryonated hens' eggs into the yolk sac, and cultures of various tissues with equal quantities of virus. Evidence is presented that cultures of embryonic chick tissue can be made as efficacious as suckling mice for the primary isolation of this virus by increasing the volume of the inoculum. On the basis of these findings and in view of the practical advantages of the tissue culture method it is concluded that cultures of embryonic chick cells should provide a satisfactory technic for use as routine in the etiologic diagnosis and in epidemiologic studies of eastern equine encephalomyelitis.