Levels of Resistance to Pyrethroid among Distinct kdr Alleles in Aedes aegypti Laboratory Lines and Frequency of kdr Alleles in 27 Natural Populations from Rio de Janeiro, Brazil.

The NaVR1 and NaVR2 kdr alleles confer resistance to the pyrethroid deltamethrin in homozygotes and R1R2 heterozygotes, being the R2R2 most resistant genotype. The allele containing duplication in the NaV gene, with a mutation in the 1011 site, did not confer resistance under the tested conditions. The frequencies of the "resistant genotypes" are elevated in Ae. aegypti natural populations from Rio de Janeiro.