§ Mr. Biffenasked the Minister of Agriculture, Fisheries and Food what is the latest evidence he has of the prevalence of warfarin-resistant rats; what new areas have been infected over the past 12 months; and if he will make a statement.
§ Mr. Anthony StodartMy latest information is that the Warfarin-resistant common rat persists in two main areas of England and Wales. The first centres on Welshpool and now extends over some 2,500 sq. miles the other consists of about 180 sq. miles in Kent. During the past 12 months we have also established that some pockets of Warfarin-resistant ship rats exist on Merseyside but there is no evidence that they are spreading.
§ Mr. Biffenasked the Minister of Agriculture, Fisheries and Food what studies and what budget are devoted by Government research establishments to the production of methods of rodent control to take account of the developing numbers of rats that are now resistant to Warfarin.
§ Mr. Anthony StodartThis continues to be a key feature of the work of my Department's Pest Infestation Control Laboratory, where research is being undertaken in co-operation with the World Health Organisation.
200WWe are attacking this problem on three fronts: first, in an effort to find a formulation which would restore the potency of Warfarin; second, to discover some other effective rat poison which would be equally safe; and finally, to devise alternative methods of control. Twenty-one staff are at present engaged on this work, at an annual cost, including equipment and materials of about £65,000 a year.
§ Mr. Biffenasked the Minister of Agriculture, Fisheries and Food what is the estimated rat population of the United Kingdom; what has been the recent trend in estimated numbers; and what assessment has been made of public health hazards on account of the growing areas affected by Warfarin-resistant rats.
§ Mr. Anthony StodartThe latest annual returns from local authorities in England and Wales, covering the four years 1966–69, suggest that the number of rat-infested premises is declining slightly in urban areas but showing a slight increase in the countryside. Similar trends have been discerned in Scotland and Northern Ireland.
The relative degree of infestation in Warfarin-resistant areas is no greater than elsewhere. Any assessment of public health hazards is a matter for the local authorities concerned.