VIRULENCE ASSAY OF COCCIDIOIDES IMMITIS IN EMBRYONATED EGGS

Publisher Website
Google Scholar
Abstract
Embryo deaths were proportional to the amount of fungus injected, the majority occurring between the third and sixth day following yolk sac inoculation of 5-day-old embryonated eggs. Injections in the allantoic fluid did not give a satisfactory response. Five-day-old embryos were more susceptible than older embryos. Growth of the fungus in the egg reached 106 particles whether or not death of the embryo occurred. Death of the embryo was not due to mechanics of injection or to the effects of chemical or nonviable biological material injected with the fungus. It also was concluded that death probably was not the result of depletion of nutrients in the yolk. The virulence of 37 strains of C. immitis was determined by this technique. The LD50 values ranged, with one exception, between 4 and 2,800 viable particles.