Simultaneous Cultivation of Typhus Rickettsiae and Influenza Virus in the Developing Chick Embryo

Abstract

Summary and Conclusions

(1) Developing chick embryos were inoculated with rickettsiae of typhus fever, following which the same eggs were reinoculated with the virus, of influenza. Two strains of rickettsiae were employed, namely, the Breinl strain of epidemic typhus and the Castaneda strain of murine (endemic) typhus. Also, 2 strains of influenza virus were employed, namely, the PR8 strain of influenza A and the Lee strain of influenza B. The groups of developing chick embryos inoculated with typhus and influenza, included the 4 possible combinations of rickettsiae and virus, viz. epidemic typhus-and influenza A, epidemic typhus and influenza B, murine typhus and influenza A, and murine typhus and influenza B.

(2) Rickettsiae, inoculated into the yolk sac, were recovered from the yolk sac membranes, and typhus vaccines were prepared therefrom.

(3) Influenza virus, inoculated into the allantoic cavity, was recovered from the allantoic fluid and influenza vaccines were prepared therefrom.

(4) All the vaccines passed the requirements established for typhus and influenza vaccines produced in this laboratory.

(5) There was no evidence of immunity to influenza in the mice inoculated with typhus vaccine, and conversely, there was no evidence of immunity to typhus in the mice receiving immunizing doses of influenza vaccine.