Date Approved


Graduate Degree Type


Degree Name

Biology (M.S.)

Degree Program


First Advisor

Dr. Jennifer Moore

Second Advisor

Dr. Kristin Renkema

Third Advisor

Dr. Kevin Strychar

Academic Year



The federally threatened eastern massasauga rattlesnake is faced with many threats, including the newly recognized snake fungal disease. Unfortunately, the immune response to the disease is unknown. Leukocyte profiles are used as health assessment tools for many species, and imaging flow cytometry can be used as an application to characterize leukocyte profiles. Our goal was to use imaging flow cytometry to identify leukocyte profiles of eastern massasauga rattlesnakes and determine differences in profiles between sexes, reproductive status, ages, location, and individuals with clinical signs of snake fungal disease. Blood samples from 201 individuals were collected from ten locations throughout the Lower Peninsula of Michigan from May through August in 2018 and 2019. We captured 29 individuals with clinical snake fungal disease signs over the sampling period. We used imaging flow cytometry to enumerate and sort leukocytes, generating leukocyte profiles. Our eastern massasauga leukocyte profiles contained lymphocytes most abundantly, followed by heterophils, then eosinophils, basophils, azurophils, and least abundantly monocytes. We found that adult eastern massasauga rattlesnakes have lower mean total leukocytes compared to juvenile and young snakes. Gravid female snakes have lower basophil counts compared to non-gravid females. We also observed a trend of higher leukocyte counts associated with severe clinical signs of SFD. Our study furthers the understanding of leukocyte profiles of eastern massasaugas.

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