§ Dr. Strang
To ask the Minister of Agriculture, Fisheries and Food what is the total number of outbreaks of sheep scab in the United Kingdom in the 12 months prior to deregulation; how many outbreaks of sheep scab there have been in the United Kingdom in the last 12 months; and in which areas of the United Kingdom sheep scab has been found since the deregulation of the disease.
§ Mr. Waldegrave
The total number of confirmed cases of sheep scab in the United Kingdom between 1 July 1991 and 30 June 1992 was 195. The collation of official records on the number of sheep scab outbreaks in Great Britain was discontinued after deregulation. In Northern Ireland, where sheep scab remains a notifiable disease, there have been 61 outbreaks over the last 12 months.
Industry reports have indicated that sheep scab has been discovered in every county in Britain. A surveillance exercise during the spring identified 177 batches of sheep suspected of having sheep scab from 869 visits to sheep sales and markets. These and other reports confirm that the disease is probably spread across the whole country.
The Government announced on 17 May that they would conduct a publicity campaign and increase the official veterinary presence at sheep markets. Surveillance at 766 market days since 1 September has resulted in 44 animals with sheep scab being withdrawn from sale and treated. These animals were found at markets in north Humberside, south Wales, the highland region and borders region of Scotland.
§ Dr. Strang
To ask the Minister of Agriculture, Fisheries and Food what steps are being taken to monitor the development of resistance of sheep scab to insecticides in the United Kingdom; and what information he has on the insecticides sheep scab has developed resistance to in other Countries.
§ Mr. Waldegrave
Sheep scab was notifiable in the United Kingdom between 1974 and 1992, with the compulsory national dipping of sheep in organochlorine, organophosphate or synthetic pyrethroid plunge dip formulations. During this period, there were no reported incidences of dip formulations failing to be effective. Monitoring for insecticide resistance in United Kingdom populations of sheep ectoparasites—including the sheep scab mitePsoroptes ovis—has been undertaken for the past three years, under a Government-funded research project. There is no current evidence to suggest that the scab mite is resistant to any licensed synthetic pyrethroid or organophosphate formulation applied to sheep in the United Kingdom.
In Argentina, the sheep scab mite developed resistance to the organochlorine insecticide BHC—HCH, benzene hexachloride, hexachlorocyclohexane or lindane—in 1962 and then to the OP, diazinon, in 1970. The development of resistance in both cases was directly related to the standard of Argentinian sheep husbandry. There is no evidence that similar resistance has developed elsewhere.