Abstract
Re-emergence of dengue fever is a public health concern in Japan. As insecticides are the major tool for vector control, it is important to monitor susceptibility of the vector to insecticides. However,little is known about the present insecticide resistance status of A. albopictus in Japan. Kawada et al (2010;JJID 63:19-24) reported that larvae of some populations of A. albopictus in Nagasaki City had strong resistance to d-allethrin. Later we found that resistance to permethrin in the adult stage was limited in some of these populations, and high resistance to DDT in the adult stage was common in all the populations tested. It is yet to be clear how Nagasaki populations have developed resistance to pyrethroids and whether it is related to the resistance to DDT. We aimed to investigate the resistance to pyrethroids and DDT in A.albopictus population from several places in Japan to compare with Nagasaki populations. These include strains originated from several cities and populations from southern islands,Amami and Yonaguni. High DDT resistance was found in all samples except the Yonaguni population. Permethrin resistance was detected in a half of the sites. It is likely that the DDT resistance developed by extensive use of this chemical in the past still remains in A.albopictus populations widely in Japan. However DDT resistance may not be the cause of the pyrethroid resistance that was observed sporadically from different places.
