Answers are grounded in this paper and cite their sources.
The attenuated M-44 strain of Coxiella burneti was heated to free it of adventitious agents that may have been present. Parallel titrations of the strain before and after heating indicated that the virulence for guinea pigs was markedly decreased. Guinea pigs immunized with the strain derived after heat treatment were protected from the effects of challenge with C. burneti in either phase I or II.
No takes yet. Share an insight, caveat, or question.
Robinson et al. (1974) studied this question.
Synapse has enriched 10 related papers. Consider them for comparative context: