Date of Award

Winter 2010


© 2010 Thomas Siemens

Document Type


Degree Name

Master of Science in Marine Sciences


Marine Science

First Advisor

Frank Daly

Second Advisor

Dave Rotstein


Phocine Distemper Virus (PDV) is a Morbillivirus that has been responsible for the death of approximately 40,000 phocid seals in the last three decades. The most commonly reported pathology is virally induced demyelination of the cerebrum and brainstem which leaves axons bare and limits their conductivity of action potentials. While these conditions have been studied at length, there is little mention of spinal cord involvement. This study aims to determine whether demyelination found in the brainstem continues into the cervical spinal cord. The results indicate that demyelination in the cervical spinal cord does not occur alongside the brainstem. It is shown, however, that lower motor neurons in the ventral horn of cervical segments 3-5 are indeed affected by Morbillivirus infection in that they undergo chromatolysis and begin to decrease in size. Such neuronal damage then leads to compromised innervations of the upper extremities, neck, and most importantly the diaphragm leading to lethargy and respiratory failure.


Master's thesis