Animal Science and Technology


Petersson, Katherine

Advisor Department

Animal and Veterinary Science




Haemonchus contortous, fistulated ewe, in vivo, animal science technology, parasite capsule, ruminant


My honors project examined one aspect of an overarching research project currently happening here at the University of Rhode Island studying the parasite Haemonchus contortus. This project focused on revising the current working assay for in vivo exsheathment of the parasite in cannulated ewes in order to find more cost effective materials and shorten the length of time the assay takes to complete. Haemonchus contortus, commonly known as the barber pole worm, inhabits the digestive tract of sheep and goats. It feeds on the blood in the abomasum, a chamber of the ruminant stomach, and causes anemia and sometimes death in susceptible animals. The focus of Dr. Petersson’s research is the identification of alternative methods of parasite control through the feeding of forages and other plants containing bioactive compounds with anti-parasitic properties. The mechanism of action of these forages and plants on various stages of the parasite life cycle are studied. During exsheathment, the parasite sheds their outer cuticle in the rumen and becomes fully infective to the animal. This stage occurs in the rumen prior to passing into the abomasum (gastric stomach, similar to human stomach) where it feeds on blood. It is important to be able to study the rate of exsheathment, which is done via the in vivo assay, in order to understand how or if the anti-parasitic properties and mechanisms of action of these forages could hinder or stop the exsheathment process thereby keeping the parasite from becoming fully infective. By reworking the assay, the ability to study the exsheathment processes was made more accessible. To rework the assay, the capsules being currently used were modified. Those modified larvae containment devices were compared to the original capsule on usability, efficacy, and affordability.