Resistance to anticoagulants in Europe
Commensal rodents are mainly controlled by anticoagulant rodenticides. Resistance to the first successful anticoagulant, warfarin, was detected in the Norway rat (Rattus norvegicus) in 1958 and then expanded to other rodent species (R. rattus, Mus musculus) and the majority of other anticoagulants. The EPPO Panel on Rodent Control felt that it was useful to give an up-to-date picture of the current distribution of anticoagulant resistance in Europe and for this purpose a questionnaire was sent in 1992. 13 countries answered and it appeared that a broad-spectrum resistance to anticoagulants (e.g. warfarin, diphacinone, coumatetralyl, bromadiolone, difenacoum, brodifacoum) occurs at least in all countries which have conducted tests (e.g. Denmark, Finland, France, Germany, United Kingdom). In other countries, documented reports also show the occurrence of anticoagulant resistance. It is felt that true distribution of resistance is probably more extensive than documented by the replies of this questionnaire. In addition, the EPPO Panel on Rodent Control also found that the existing resistance detection protocols were no longer adequate and therefore a new guideline containing new tested methods is now being discussed.
Sources
Myllymäki, A. (1995) Anticoagulant resistance in Europe: appraisal of the data from the 1992 EPPO questionnaire.
Pesticide Science, 43(1), 69-72.