Potential anthelmintic properties of urea

Abstract

Current gastrointestinal parasite treatment options rely heavily on chemical anthelmintic intervention which targets the nematode residing in the host. However, targeting these organisms during parts of their lifecycle outside the host may also provide a tool for aiding control. In particular, nitrogenous fertilisers produce several potentially toxic compounds, the strategic use of which may affect nematode development. This series of experiments investigated the potential of liquid urea to affect gastrointestinal nematode development. Hatching of Trichostrongylus colubriformis eggs when immersed in liquid urea reduced with increasing urea concentration from 90% at 0% urea to less than 6% in 20% urea solution. This effect was independent of pH and appeared to be nematocidal rather than nematostatic as unhatched eggs failed to hatch following washing and immersion in water. Further, topical application of liquid urea to faeces at a rate equivalent to 200 litres per ha (40 units N) on fresh faeces resulted in a 97% reduction in the number of larvae recovered following culturing compared with equivalent rates of water (P<0.01). Although further studies and refinement are required, these studies indicated targeted application of liquid urea may be a useful tool to assist with parasite control.