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Aedes albopictusis a globallydistributed mosquito vectorresponsible for the transmission of important arboviruses, such as dengue, yellow fever, and chikungunya viruses. The recent outbreak of Zika infection has become an international public health emergency.

Since no effective vaccines for protection against these viral infections, the mosquito control has been and will be one of the most effective measures to reduce the transmission.

Aedes albopictus也Ae. aegyptihas been shown to be able to transmit Zika, although the vector competence was pretty low in两种蚊子. Since no effective vaccines for protection against these viral infections, the mosquito control has been and will be one of the most effective measures to reduce the transmission.

Pyrethroids have been utilized for mosquito control since the 1980s in China. The resistance to pyrethroids has been documented in several populations ofAe. albopictusin China. Due to the Dengue outbreaks in Hainan Island in the 1980s, intensive applications of pyrethroid ultra low-volume spray to kill flying adult mosquitoes have posed significant pressure on mosquitoes.

Pyrethroid resistance populations ofAe. albopictushave been present in Hainan since the 2000s. InAedes aegypti,mutations in the gene encoding voltage-gated sodium channels (VGSC) are responsible for the knockdown resistance (kdr) to DDT and pyrethroids. However, nokdralleles had been associated with pyrethroid resistance inAe. albopictus.

We examined the larval susceptibility to deltamethrin, permethrin and beta-cypermethrin in five collections from Haikou city in Hainan Island

In this research paper, we examined the larval susceptibility to deltamethrin, permethrin and beta-cypermethrin in five collections from Haikou city in Hainan Island. Two populations in the city sites showed high level of resistance to the pyrethoids tested, and at codon F1534 of VGSC gene, three kdr mutant alleles were identified, namely, TCC(S), TGC(C) and TTG(L), in addition to wildtype TTC(F).

The kdr alleles were associated with the resistance phenotype. The kdr allele TTC(S) was dominant in the resistant individuals, with frequency of 31.4% in 493 examined specimens. InAe. aegyptiF1534C was the most common mutant allele in the pyrethroid resistant populations.

Further studies are underway to examine the genotypes of other possible mutation sites in the VGSC gene in Hainan populations.Aedes albopictusis an invasive species. There is the risk that resistant populations may disseminate to other continents globally.