Background: Anopheles sinensisis a principal vector forPlasmodium vivaxmalaria in most parts of China. Understanding of genetic structure and genetic differentiation of the mosquito should contribute to the vector control and malaria elimination in China.Methods: The present study investigated the genetic structure ofAn. sinensispopulations using a 729 bp fragment of mtDNAND5among 10 populations collected from seven provinces in China.Results: ND5was polymorphic by single mutations within three groups ofAn. sinensisthat were collected from 10 different geographic populations in China. Out of 140 specimens collected from 10 representative sites, 84 haplotypes and 71 variable positions were determined. The overall level of genetic differentiation ofAn. sinensisvaried from low to moderate across China and with aF_STrange of 0.00065 – 0.341. Genealogy analysis clustered the populations ofAn. sinensisinto three main clusters. Each cluster shared one main haplotype. Pairwise variations within populations were higher (68.68%) than among populations (31.32%) and with high fixation index (F_ST = 0.313). The results of the present study support population growth and expansion in theAn. sinensispopulations from China. Three clusters ofAn. sinensispopulations were detected in this study with each displaying different proportion patterns over seven Chinese provinces. No correlation between genetic and geographic distance was detected in overall populations ofAn. sinensis(R² = 0.058;P = 0.301).Conclusions: The results indicate that theND5gene of mtDNA is highly polymorphic inAn. sinensisand has moderate genetic variability in the populations of this mosquito in China. Demographic and spatial results support evidence of expansion inAn. sinensispopulations.

In 2009, residents of Lhasa city, Tibet Autonomous Region (TAR), China reported large numbers of mosquitoes and bites from these insects. It is unclear whether this was a new phenomenon, which species were involved, and whether these mosquitoes had established themselves in the local circumstances. The present study was undertaken in six urban sites of Chengguan district Lhasa city, Tibet. Adult mosquitoes were collected by bed net trap, labor hour method and light trap in August 2009 and August 2012. The trapped adult mosquitoes were initially counted and identified according to morphological criteria, and a proportion of mosquitoes were examined more closely using a multiplex PCR assay. 907 mosquitoes of the Culex pipiens complex were collected in this study. Among them, 595 were females and 312 were males. There was no significant difference in mosquito density monitored by bed net trap and labor hour method in 2009 and 2012. Of 105 mosquitoes identified by multiplex PCR, 36 were pure mosquitoes (34.29%) while 69 were hybrids (65.71%). The same subspecies of Culex pipiens complex were observed by bed net trap, labor hour method and light trap in 2009 and 2012. The local Culex pipiens complex comprises the subspecies Cx. pipiens pipiens, Cx. pipiens pallens, Cx. pipiens quinquefasciatus and its hybrids. Mosquitoes in the Cx. pipiens complex, known to be, potentially, vectors of periodic filariasis and encephalitis, are now present from one season to the next, and appear to be established in Lhasa City, TAR.