Our experiments have shown that the Mooser bodies or Rickettsiae derived from guinea pigs with Mexican typhus fever can survive in bedbugs after intra-coelomic injection for 10 days, remaining capable of infection. We have also succeeded in similarly infecting bedbugs by allowing them to feed on benzolized rats in whose blood Rickettsiae had been shown to be present. Injection of the organs of such bedbugs 5 days after the last, 9 days after the first infectious feeding into guinea pigs produced typical Mexican typhus fever.
Some of the guinea pigs infected with such bedbug organs and passing through a typical typhus proved to be immune to subsequent inoculation with the European disease.
Attempts to infect normal guinea pigs by allowing infected bedbugs to feed on them or by rubbing the feces into the uninjured skin have, so far, been unsuccessful.
We have not, therefore, completed the cycle proving that bedbugs can transmit the disease, but we have shown that this is a possibility when dealing with man, obviously more susceptible to the disease than any of our experimental animals.
The ease with which the Rickettsiae seem to survive in the bedbugs suggests the desirability of investigating other common insects for a similar capacity of harboring the typhus Rickettsiae-experiments which we have not yet had the time to carry out.