Janine Grace Lock will defend her master's thesis in Environmental Sciences, Parasite communities and their identification in wild and domestic herbivores in Iceland at the Faculty of Nature and Forest Sciences at the Agricultural University of Iceland.
Janine Grace’s supervisors are Dr. Isabel Barrio, Agricultural University of Iceland, Dr. Susan Kutz, University of Calgary and Mathilde Defourneaux, PhD candidate - Agricultural University of Iceland.
The examiner is Kristbjörg Sara Thorarensen veterinarian at Keldur, Institute for Experimental Pathology.
The master's defence will take place on Tuesday, June 25, 2024, at 2 PM in Sauðafell, on the 3rd floor in Keldnaholt, Reykjavík, and on Teams. Link here. The defence is open to everyone and is presented in English.
Abstract
Gastrointestinal parasites affect the health of individual animals, their herds and other animal populations overlapping in range and diet. The maintenance of parasites within a host population or within an ecosystem depends in part on parasite species overlap between different host species. Parasite maintenance within a population also has implications for treatment of gastrointestinal parasites using anthelminthics, and can contribute to anthelminthic resistance.
The objectives of this research were to study the current status of gastro-intestinal nematode communities in three main Icelandic herbivores, domestic sheep (Ovis aries), wild reindeer (Rangifer tarandus tarandus), and pink-footed goose (Anser brachyrhynchus). In this studyparasite community composition overlap of host species was compared to better understand the possible risk of common parasites between host species. Strongyle-type eggs were found both in sheep and reindeer when identified morphologically. Nemabiome analyses of larvae hatched from these eggs identified Teladorsagia circumcincta, Haemonchus contortus, and Trichostrongylus axei, however these results need further confirmation.
This study was the first to look at the gastrointestinal parasite fauna of pink-footed geese in Iceland, finding a strongylida that matched the description of Trichostrongylus tenuis which has been seen in other Icelandic birds. Furthermore, I tested the use of a novel diagnostic technique, that uses near and mid infrared reflectance spectrometry (NIRS and MIRS) to identify parasites to the species level within a fecal sample.
This new diagnostic technique relied on the development of cost-effective and accessible models that can accurately predict parasite species in fresh and frozen sheep and reindeer dung samples. Eighteen separate models were created using three frameworks on six different datasets, for sheep and reindeer. The three datasets per host varied by how the fecal samples were stored and the type of spectrometry used (fresh NIRS, frozen NIRS and fresh MIRS).
The models were trained using random forest multi-label classification algorithms with binary relevance (BR), classifier chain (CC) and label powerset (LP) frameworks to calibrate NIRS and MIRS spectra to nemabiome results. All models were able to identify parasite species from frozen samples, however label powerset (LP) framework offered the best model performance results overall, highest accuracy, average-precision and F1 scores. MIRS moderately outperformed NIRS for sheep and strongly outperformed NIRS for reindeer datasets using the TM and CC frameworks.
This study explored nematode community composition overlap between wild and domestic herbivores in Iceland, finding potential nematode commonalities between sheep and reindeer. Secondly, this study found NIRS and MIRS to have potential as future gastrointestinal parasite diagnostic techniques.
