LE3 .A278 2012

2012

Smith, Todd

Acadia University

Bachelor of Science

Honours

Biology

Biology

Hepatozoon clamatae and Hepatozoon catesbianae are malaria-like parasites that infect the erythrocytes of frogs in eastern Canada. Although green frogs (Rana clamitans) and bullfrogs (Rana catesbeiana) are commonly infected with Hepatozoon species, these parasites have a low prevalence and parasitaemia in wood frogs, Rana sylvatica. The ability of wood frogs to freeze during the winter may account for these observations, as it is currently not known whether or not these blood parasites can survive sub-zero temperatures. The objectives of this study were first to determine the host specificity of the two Hepatozoon species for wood frogs, and second, to observe the effects of freezing on these parasites. Egg masses and adult frogs were collected during spring breeding. Blood smears revealed that four of 24 adults were infected with H. catesbianae. After metamorphosis, 21 metamorphs were fed mosquitoes with mixed infections of H. clamatae and H. catesbianae. Eight of these frogs were positive for H. catesbianae, and two of these eight were additionally infected with very low levels of H. clamatae. Four infected metamorphs and two infected adults were acclimated at 4 C for 4 wk, after which they were frozen at -3 C for 2 d. Four infected metamorphs and two infected adults were not frozen and served as controls. In both frozen adults and metamorphs, parasitaemia dropped considerably relative to the controls. This study suggests that wood frogs are suitable hosts for H. catesbianae, but likely not for H. clamatae, and based on preliminary data, that freezing reduces the parasitaemia of Hepatozoon species in wood frogs, which may account for the low prevalence and parasitaemia values from the literature.

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https://scholar.acadiau.ca/islandora/object/theses:885