Volume 11, Issue 1
  • ISSN: 0002-9637
  • E-ISSN: 1476-1645



Experiments were conducted with albino mice to evaluate several variables in the production of acquired resistance, or “immunity”, to infection. These variables included: (1) the number of “immunizing” cercarial exposures; (2) the time from initial “immunizing” exposure and final immunizing exposure until the challenge exposure by the same parasite; and (3) the size of the challenge exposure.

The results indicate that: (1) a limited number of cercarial exposures are no more effective in producing “immunity” to a challenge infection than is a single exposure to the same total number of parasites; (2) a period of approximately 60 days from the initial exposure to a challenge exposure is necessary for a demonstrable “immunity” to the challenge infection; and (3) different sizes of challenge exposures, after a uniform “immunizing” infection, do not prevent the demonstration of acquired resistance. These results appear consistent with the hypothesis that maturity of the initial infections with egg deposition is necessary before “immunity” to a challenge exposure with can be demonstrated.


Article metrics loading...

The graphs shown below represent data from March 2017
Loading full text...

Full text loading...

This is a required field
Please enter a valid email address
Approval was a Success
Invalid data
An Error Occurred
Approval was partially successful, following selected items could not be processed due to error