Markers for the detection of anthelmintic resistance - from farm to gene level

Parasitic nematodes cause serious disease problems in both plants and animals worldwide. When infections can no longer be controlled, health, welfare and production are affected. Animals are therefore often treated with anthelmintics.

Especially for parasites in grazing animals, incorrect deworming has driven the development of resistance, but increasingly also in other animal species and in humans. In the project, we will use epidemiological and genetic tools to find out what causes resistance to anthelmintics in the bloodsucking large roundworm Haemonchus contortus, which parasitises sheep.

First, we will use GWAS (whole genome sequencing combined with bioinformatics analysis) to identify gene variants in adult worms that are associated with resistance. The presence of the detected gene variants in pooled parasite samples from at least 40 randomly selected farms will then be further investigated by generating SNP arrays.

On farms, we will also measure the resistance by calculating the reduction in egg laying of the parasite after deworming. Data on animal flows and deworming routines will also be collected. This will allow us to calculate risk factors related to the resistance status of the farms. Finally, new genetic tests based on digital PCR technology are being developed. This will allow even more comprehensive research by linking the genetic results with the treatment effect measured in the traditional way.

The long-term goal of the project is to develop molecular diagnostic tools for detecting resistance that can be used routinely. By monitoring the situation, we can better understand how resistance develops and how further spread can be prevented.