Are there indications of anthelmintic resistance in reindeer gastrointestinal parasites following treatment with ivermectin?

Objective

The objective is to evaluate the efficacy of ivermectin against gastrointestinal parasites in reindeer, including possible indications of anthelmintic resistance and changes in the parasite community composition before and after treatment.

Background

In reindeer husbandry, ivermectin is routinely used to treat warble fly (Hypoderma tarandi) infections, but the treatment also affects gastrointestinal parasites. In other ruminants, such as sheep and cattle, there are well-documented cases of anthelmintic resistance against ivermectin. Since reindeer are increasingly kept at high stocking densities during winter feeding, conditions may now resemble those in domestic livestock, making resistance development plausible. There is therefore a need to investigate whether signs of resistance are emerging in reindeer as well.

Project description

Implementation

The project is best initiated during the second study period of autumn 2025. The student may participate in field sampling if starting in autumn; for spring 2026 starts, the project will focus on lab work and data analysis. Since larval cultures require up to two weeks, time can be used for parallel analyses or coursework. The project can be completed as a 45-credit thesis or as a 30-credit thesis combined with another course.

Method

Fecal samples will be collected from 20 calves in each of four reindeer herding communities, both before and 14 days after ivermectin treatment. Samples will be analyzed using the McMaster method to determine eggs per gram (EPG), and larval cultures will be established to harvest larvae. DNA will be extracted from the larvae and subjected to molecular identification via ITS2 sequencing (metabarcoding using the Illumina sequencing platform). Data will be analyzed using DADA2 to assess species composition before and after treatment. Resistance will be evaluated through fecal egg count reduction (FECR) according to WAAVP guidelines for livestock ruminants.

Expected results

• Indications of anthelmintic resistance based on FECR values.
  
• Species composition of nematodes before and after treatment.

Specifications

Suitable for veterinary students, animal science/agronomy students, and biology students interested in parasitology and/or molecular biology.