LE3 .A278 2014

2014

Smith, Todd

Acadia University

Bachelor of Science

Honours

Biology

Biology

Hepatozoon catesbianae is a malaria-like parasite that commonly infects the erythrocytes of frogs of Eastern Canada. Although green frogs (Rana clamitans) and bullfrogs (Rana catesbeiana) are commonly infected with Hepatozoon species, these parasites have a low prevalence and intensity in wood frogs, Rana sylvatica. These observations may be explained by the inability of parasites to survive when wood frogs freeze during the winter. The objective of this study is to determine if freezing of experimentally infected wood frogs affects the prevalence and parasitaemia, which is defined as the percentage of blood cells infected with a parasite, of H. catesbianae. Tadpoles hatching from egg masses collected in April 2012 were raised to adulthood by summer 2013. Mosquito larvae, and green frogs that served as a source of infection, were collected in summer 2013. A total of 20 wood frogs were fed mosquitoes with infections of H. catesbianae, and 13 became infected with H. catesbianae. Five infected wood frogs were assigned to the experimental group, five other infected wood frogs remained unfrozen as controls, and the infections in three frogs were not mature. The experimental group was acclimated at 4 C for a period of 4 weeks, after which the frogs were frozen at -3 C for 48 hr, and subsequently thawed at 4 C for a period of 6 days. Following the post-freezing recovery period, blood samples were taken from the experimental and control groups and were examined for H. catesbianae. Data from this study were combined with that of Hammer (2012) and McGee (2013) and were subjected to statistical analysis to test if sub-zero temperatures reduces the parasitaemia of H. catesbianae in wood frogs. Although there was a significant difference in the decrease of parasitaemia levels of H. catesbianae over time, this decrease was not attributed to freezing.

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https://scholar.acadiau.ca/islandora/object/theses:1115