The honey bee tracheal mite, Acarapis woodi (Rennie) is spread almost throughout the entire world, with some exceptions, for instance, Australia and the Caribbean. Among Scandinavian countries, it has not been reported from Sweden or Norway. A. woodi is a very serious problem in the USA, partly because of migratory beekeeping, and partly because the detection of this mite is time consuming and difficult. According to Otis', diagnostic examinations of honey bees for tracheal mites are estimated to cost over US$10 million per annum, world-wide. Movement of colonies from one state to another is allowed only with a health certificate, which according to Korpela and Fakhimzadeh, however, is of limited value (see example of the importation of 2000 queens to Finland in the summer of 1991, reported below).