Gastrointestinal parasites in sympatric reindeer (Rangifer tarandus) and sheep (Ovis aries) - Evidence of spillover and consequences thereof

• Main Author: Robertsen, Per-Anders
• Format: Master Thesis
• Language: English
• Published: 2020
• Subjects: Rangifer tarandus; Ovis aries; reindeer; sheep; gastrointestinal parasites; cross-transmission; gastrointestinal nematodes; Ostertagia gruehneri; Teladorsagia circumcincta; Spiculopteragia boehmi; Nematodirus battus; reinsdyr; sau; gastrointestinale parasitter; smitteoverføring; gastrointestinale nematoder; VDP::Landbruks- og Fiskerifag: 900; Karasjok; Nordfjella; Norway; reindeer husbandry; Reinsdyr
• Online Access: https://hdl.handle.net/11250/2660559

Understanding the role of gastrointestinal parasites for ecosystems and their potential impact on their hosts is valuable knowledge within wildlife management. In Norway, there is a long tradition mountain grazing for sheep, meaning that domesticated sheep and reindeer often share rangeland. This study aimed to investigate spillover of gastrointestinal parasites between domesticated sheep (Ovis aries) and wild and semi-domesticated reindeer (Rangifer tarandus) for the areas of Nordfjella zone 2, Forollhogna, and Knutshø, with medium to high, respectively, of sheep grazing intensity. Karasjok Vestre, a reindeer husbandry with very low overlap of sheep on the rangeland, was included as a control area. Parasite prevalence, abundance, intensity and richness for all study areas are reported. Parasite abundance and species richness as well as proportion of sheep parasites were statistically modelled in relation effect of temperature, precipitation, age and study area. In addition, abundance of abomasa nematodes in Knutshø and Forollhogna was compared with the last known historical record of nematode counts from these areas. I detected gastrointestinal spillover in all areas with medium to high sheep grazing intensity, namely Nordfjella sone 2, Forollhogna and Knutshø. Most importantly, I report the first detection of Nematodirus battus in this study. This invasive duodenum nematode was present in the three areas with medium to high sheep grazing intensity. This parasite is common in sheep, especially lambs, and can cause high morbidity and mortality in these hosts. It is unknown what occurs in reindeer, but pathological effects may be similar. I also detected Spiculopteragia boehmi, a parasite thought to host specific to red deer (Cervus elaphus) and roe deer (Capreolus capreolus), but has now been found in several other ruminate hosts as well as the semi-domesticated reindeer included in this study and within wild reindeer in Nordfjella sone 2. I conclude that gastrointestinal parasite spillover from sheep to ...