The use of moxidectin for the prevention and treatment of psoroptic mange (scab) in sheep

The introduction of systemic injectable products, belonging to the avermect in/milbemycin class of antiparasitic compounds, has provided an alternative to dips for sheep scab control. Their main advantages are that they are qu icker and safer to use, cause less stress to the sheep (hence can be used i n heavily pregnant ewes), do not require any special handling facilities fo r their use and do not present the same environmental concerns over disposa l of spent product. Moxidectin, a second generation milbemycin, has recently been registered as an injectable product for the prevention and treatment of sheep scab. Labo ratory and field studies carried out in the UK and ireland have shown that two injections at a dose rate of 200 mg/kg bwt., 10 days apart, are 100% ef fective in the treatment of scab. Further studies have shown that a single injection at the same dose rate will protect against infestation or reinfes tation for a period of at least 28 days. This long persistent activity has been evaluated in two large-scale field prophylactic trials, one in Ireland and one in the UK, involving over 16,000 sheep, in which it was demonstrat ed that a single injection of moxidectin is a safe and effective alternativ e to dips for routine prevention of scab. (C)1999 Elsevier Science B.V. All rights reserved.