The purpose of this investigation was to determine factors which may influence the survival time of mice infected with Trypanosoma equiperdum and the effects of T. equiperdum on mice infected with Schistosoma mansoni.

In order to maintain experimentally obtained standard hours of survival (88 hrs) in mice inoculated intraperitoneally with 150,000 T. equiperdum, it was found that trypanosomes removed from the donor rat should be kept at 25 C and all counts, dilutions of the organisms, and injection should be completed within 1 hour after removal from the donor host. Survival time of mice is increased as the interval between removal and inoculation of the organisms increases. Parasites kept at 25 C from 0.5 to 8.0 hours killed all of the mice in the tests, but only 3 out of 5 died when they were infected at the 11.5 hour interval. Parasites kept at 37 C from 0.5 to 2.0 hours killed all the mice, but only 13 out of 20 died when they were infected at the 2.5 hour interval.

Blood taken at different durations of parasitemia from donor rats and injected into mice do not affect the survival time of mice, but a slight loss in virulence is observed when the parasites were obtained 10 minutes after the death of the donor.

The ages and weights of mice infected with T. equiperdum have no effect on their survival time (ave. = 91.1 hrs).

In concurrent infections of Schistosoma mansoni and Trypanosoma equiperdum, there is no significant difference between survival time of mice infected with trypanosomes during the early stages of schistosomiasis and corresponding controls. Mice infected with trypanosomes after the 5th, 7th, and 9th week of schistosome infection die significantly earlier than controls. It is suggested that a synergistic effect is produced in the mixed infection of S. mansoni and T. equiperdum.

The correlation between the hours of survival and the number of adult schistosomes recovered is not significant.

LLU Discipline





Graduate School

First Advisor

Edward D. Wagner

Second Advisor

Earl W. Lathrop

Third Advisor

Ariel A. Roth

Degree Name

Master of Arts (MA)

Degree Level


Year Degree Awarded


Date (Title Page)




Library of Congress/MESH Subject Headings

Schistosoma mansoni; Trypanosoma



Page Count

vii; 24

Digital Format


Digital Publisher

Loma Linda University Libraries

Usage Rights

This title appears here courtesy of the author, who has granted Loma Linda University a limited, non-exclusive right to make this publication available to the public. The author retains all other copyrights.


Loma Linda University Electronic Theses and Dissertations

Collection Website



Loma Linda University. Del E. Webb Memorial Library. University Archives