LE3 .A278 2013

2013

Smith, Todd

Acadia University

Bachelor of Science

Honours

Biology

Biology

Hepatozoon catesbianae and Hepatozoon clamatae are intraerythrocytic apicomplexan parasites that infect the green frog, Rana clamitans. Dual infections of both H. catesbianae and H. clamatae are common in green frogs in eastern Canada. However, not much is known about the population dynamics of dual infections compared to single infections, and little research has been carried out on immune responses of frogs to these malaria-like parasites. The objectives of this project were 1) to study the population dynamics of dual infections of Hepatozoon species, and 2) to characterise the immune response, if any, by green frogs infected with Hepatozoon species. Specific numbers of mosquitoes, originally fed on adult green frogs with pure infections of H. catesbianae or H. clamatae, were fed to laboratory-raised juvenile green frogs. Blood samples taken every five days post-inoculation (d PI) revealed that all leucocyte levels remained constant through different time points until 25 d PI, when the number of lymphocytes and neutrophils increased greatly, and eosinophil levels decreased. Lymphocyte and neutrophils ratios began to decrease slightly at 30 d PI, at the same time as parasites were observed in the blood smears. Parasitaemia of a frog infected with both species of parasites resulted in high parasitaemia of each species, with a much greater parasitaemia of H. clamatae. The increase in lymphocyte numbers suggests participation of the acquired immune system during infection, whereas the increase in neutrophils suggests activation of the innate immune system. The increase in the ratio of H. clamatae to H. catesbianae compared to initial inoculation suggests that interspecific competition may be occurring between the two species.

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https://scholar.acadiau.ca/islandora/object/theses:943