Novel Drug Targets

Main Participants: Mary Davey, Kate Miller and John Ellis

Research improving the effectiveness of current control strategies for the sheep nematode, Haemonchus contortus

Thiol Metabolism in Haemonchus contortus The cost of internal parasites is a substantial burden to sheep production in Australia and the world. Current control methods for these parasites are restricted by the emerging problem of resistance to the currently used antihelminthic drugs. Innovative strategies are required for the development of new controls methods for these internal parasites. Haemonchus contortus, commonly known as the sheep barber’s-pole worm because of its striped appearance, is one of several gastro-intestinal nematodes of economic importance to the domestic livestock industry. Sheep become infected after ingesting a larval stage of the parasite while grazing. Current control methods involve drenching with anthelmintics combined with grazing management (e.g. pasture rotation) to limit infections. Unfortunately, resistance to the anthelmintics currently on the market is becoming widespread and so they are no longer effective. While vaccines against H. contortus are under development these will not be marketed in the near future, and there is still a need for new anthelmintics. The aim of our current research program is to identify potential new drug targets to aid in the control of this parasitic disease. Oxidative metabolism in all living cells results in the production of highly unstable and reactive oxygen-derived free radicals. An animal, such as a parasitic nematode like Haemonchus, requires the ability to maintain a balanced redox state, especially in the face of host defence mechanisms involving oxidative attack. We are investigating aspects of the host and parasite metabolism to identify target proteins that could be exploited for the treatment of infections. Our current research has focused on the enzymes involved in cellular oxidative metabolism and redox control, especially those involved in thiol metabolism. For further information contact Dr. Mary Davey or Dr Kate Miller.