Sheep scab--environmental considerations of treatment with doramectin.

The paper reviews the recent change in attitudes to dipping sheep and the proposed legal requirements to prevent and treat sheep scab. The implications of fulfillment of all the requirements of the European Groundwater Directive and the probable resultant increase of the use of injectable endectocides as an alternative to plunge dipping are discussed in relation to their likely frequency of use and potential ecological impact. In particular the properties of doramectin, one of the most recently introduced, are examined in relation to its use for the treatment of sheep scab.