Honors Theses and Capstones

Date of Award

Spring 2024

Project Type

Senior Honors Thesis

College or School




Program or Major

Animal Science

Degree Name

Bachelor of Science

First Advisor

Elizabeth Brock

Second Advisor

David Needle


From 2016 to 2023 there were 25 cases of Listeria monocytogenes diagnosed at the New Hampshire Veterinary Diagnostic Laboratory. The bacteria were isolated from samples submitted from goats, sheep, cows, gray foxes, and one rooster spread across New Hampshire, Vermont, Maine, and Massachusetts. The vast majority of the tissue samples were brain, with just one uterine culture from a goat, liver cultures from the two gray foxes, and one coelomic culture from the rooster. Bacteria were isolated using specific enrichment media (22/25) and via general bacterial culture (the rooster and both foxes) and speciated first by matrix-assisted laser desorption/ionization - time of flight (MALDI-TOF) mass spectroscopy, and then confirmed via whole genome sequencing. This study reviews the diagnostic methods used, the pathology of listeriosis, and the geospatial distribution of the cases across New England.

Available for download on Sunday, September 28, 3023