New Worm Weapons For Grazing Livestock

When sheep and cattle graze, they sometimes devour far more than a square meal. Increasingly, the grazers are becoming infected with drug-resistant parasitic worms that cause life-threatening anemia. A research team led by Ronald Kaminsky at the Novartis Animal Health Research Center, St. Aubin, Switzerland, has reported the first new class of worm—killing-but ruminant-friendly—compounds in 25 years in Nature (2008, 452, 176). The "worm weapons" are a family of amino-acetonitrile derivatives (the most potent one shown) that "will be the cause of great excitement, especially because they are active against a broad range of nematode pathogens," comment parasitologists Roger K. Prichard and Timothy G. Geary of McGill University, in Montreal, in an associated Nature commentary. The compounds paralyze the worms by targeting previously uncharacterized receptor subunits involved in the worms' neurotransmission. Knowing this mechanism of action at the outset may help monitor, if not delay, eventual drug resistance should the compounds reach the veterinary market, Prichard and Geary note.