LE3 .A278 2015

2015

Smith, Todd

Acadia University

Bachelor of Science

Honours

Biology

Biology

Hepatozoon clamatae and Hepatozoon catesbianae are intraerythrocytic apicomplexans that infect the red blood cells of green frogs and bullfrogs of Nova Scotia. Although H. clamatae and H. catesbianae have demonstrated mild host specificity in green frogs and bullfrogs, respectively, both species of Hepatozoon may simultaneously infect either species of frog. The purpose of this study is to investigate the dynamics of a dual infection of sexual stages (gamonts) of H. clamatae and H. catesbianae in the green frog, Rana clamitans, and to determine the existence of competition between these two species. Mosquitoes were fed on naturally infected green frogs, purposefully selected based on their desired parasitaemia (intensity) of Hepatozoon species. Numbers of mosquitoes to derive specific ratios of H. clamatae: H. catesbianae were fed to uninfected laboratory-reared green frogs, which were subsequently bled to assess the development of relative parasitaemia of the two species. Hepatozoon species were differentiated based on their unique cytopathological effects. Due to the unexpected persistence of erythrocytic merogony in all cohorts, species distinction was not attempted until 80 dPI in mixed infections, and merozoite intensity over time was recorded in all cohorts. Based on a linear mixed-effects model, it was determined that day of bleeding has a significant effect on parasitaemia and merozoite intensity in all cohorts. In addition, there is a trend toward a significant difference between the infection dynamics of cohort 1 and cohort 5. These results suggest that an acquired immune response may be responsible for the decline in parasitaemia over time, and with a larger sample size per cohort, the effect of competition between species may be detected by statistical methods.

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https://scholar.acadiau.ca/islandora/object/theses:1229