We utilize molecular genetic and genomic approaches to study parasitic nematode worms which include a large number of important pathogens. Parasitic nematodes are estimated to cost the US cattle industry over $2 billion per annum alone and they are major human pathogens in the developing world infecting well over a billion people. Resistance to the few available drugs is already widespread in parasitic nematodes of livestock and is an emerging problem in human parasites. The main focus of our lab is to study the mechanisms of drug (anthelmintic) resistance and to investigate how the underlying causal mutations arise and spread in parasitic nematode populations. The aim is to improve diagnosis, identify new targets for control and provide an evidence base for sustainable management of resistance.