In the Republic of Korea, public health centers conduct vector mosquito control in accordance with infectious disease prevention laws. However, most public health centers have traditionally conducted periodic, uniform vector control across their respective regions without considering specific information on vector occurrence. In 2021, The Korea Diseases Control and Prevention Agency(KDCA) launched a control project to shift the paradigm toward mosquito control strategy based on mosquito surveillance data. In 2024, 18 local public health centers will participate in this project, which will progressively expanding so that it can be used countrywide. Local public health centers evaluate mosquito monitoring data using data gathered from Daily Mosquito Monitoring System(DMS), which enables them to pinpoint the best times and locations for vector control. Vector control activities carried out by local public health centers are computerized utilizing Vector Control Geographic Information System(VCGIS). Using the new control strategy with mosquito surveillance, the number of mosquito occurrences, number of control activities, and amount of insecticides have decreased compared to the periodic control activities. Based on mosquito surveillance data, it is anticipated that evidence-based mosquito vector control will offer a more efficient and effective means of mosquito control.

Surveillance of the vectors were conducted at a total of 7 locations from March to November, 2018 in Gyeongnam province. In the surveillance, a total of 13 species belonging to seven genera were collected in a total of 15,935 females and 126.5/trap/night (TI; Trap Index) in 2018. Among the collection sites, a bird refuge in Busan, Eulsukdo recorded the highest TI 230.4 (Species Ratio; SR 60.1%) for Cx. tritaeniorhynchus females in 2018. A Cx. tritaeniorhynchus female collected firstly for 2018 in the nation at the pigsty of Busan at 1st April. In the results of isolation of viral RNA from 12 mosquito species including Cx. tritaeniorhynchus, Cx. pipiens, Ae. vexans, Ae. albopictus, and Oc. togoi. Chaoyang virus was positive at a pool of Ar. subalbatus collected at a bird refuge but negative in the other 543 pools (14,295 individuals) in 2018.

Imported 313 cases of Dengue fever and 16 cases of Zika virus disease were reported in the ROK during 2016. Aedesalbopictus has been reported as a major vector mosquito for Dengue and Zika virus. Various class of pesticides havebeen used locally different pesticide class. To investigate the pyrethroid and organophosphate pesticide resistance, genomicDNA was used for Allele-specific PCR (AS-PCR) genotyping of the acethylcholine esterase to detect Gly119Ser mutationsand kdr gene to detect Phe1534Cys mutations. Detoxification enzyme activities were assessed using Ae. albopictus fromYeosu and Jeju. Activities of four detoxification enzymes eg., glutathione S-transferase (GST), Non specific esterases (α-naphthylacetate and β-naphthyl acetate), and cytochrome C oxidase were determined for each Ae. albopictus strain. In our studies,Ae. albopictus showed only susceptible sequences for AchE and kdr. Activity of cytochrome P-450 and non specific esterasewas higher in a field population than a laboratory strain, except for GST. This study might be helpful to understandthe insecticidal susceptibility and resistant for effective vector mosquito control program.

Wolbachia is intra-cellular bacteria and frustrate host biology, such as parthenogenesis, feminization, male killing andsperm-egg incompatibility. It has been reported that > 90% of Aedes albopictus are infected with Wolbachia in the Republicof Korea (ROK). However any roles of the Wolbachia strains have not been reported in ROK. In this study, we infectedWolbachia to Vero cell line to investigate the cell migration which is related with the development of multi-cellular organisms,immune response and inflammation. Changes of wound healing and viability in vero cell after Wolbachia infection wereassessed. Cell migration was induced by Wolbachia after 24hr. Cell viability was not affected by Wolbachia after 24hr.This study will be helpful to understand the role of Wolbachia strain and support various information in Dengue andZika vector management programs.

Aedes albopictus is an important vector for yellow fever, dengue fever, chikungunya fever and Zika virus. This mosquitohas been exposed to organophosphates and pyrethroids in Republic of Korea for a long time. Using the direct contactmortality bioassay, susceptibility strain and two field populations of Ae. albopictus from Busan, and Damyang. Insecticidalproperty were indicated to RR ratio values (Resistant ratio to strain of susceptibility) of LC50 (Midian Lethal concentration)to organophosphats and pyrethroids. Genomic DNA was used for Allele-specific PCR (AS-PCR) genotyping of the acethylcholineesterase to detect Gly119Ser mutations and kdr gene to detect Phe1534Cys mutations. Detoxification enzyme activitiesof Ae. albopictus from Busan and Damyang were assessed using microplate enzyme activity assays. Activities of fourdetoxification enzymes eg., glutathione S-transferase(GST), Non specific esterases (α-naphthyl acetate and β-naphthyl acetate),and cytochrome C oxidase were determined for each Ae. albopictus strain. This study might suggest that Ae. albopictuscontrol programs should be prepared for the management of organophosphate and pyrethroid insecticide resistance.

The activities of three class, five acaricides (Permethrin, Deltamethrin, Fenitrothion, Chlorpyrifos, Imidacloprid) againstHaemaphysalis longicornis nymph, a major vector for Severe Fever with Thrombo cytopenia Syndrome (SFTS) and Lymedisease. The ticks distribute at vast open fields and various kind of habitats. Five acaricides were applied to ticks collectedform four areas(Gapyeong, Paju, Chuncheon, Wonju) to confirm the effect of acaricide. This areas was the area whereSFTS disease occurred and a large nember of ticks were collected. As a result, All areas is the most acaricidal effectto Deltamethrin. And two areas(Gapyeong, Paju) has the lowest acaricidal effect to Imidacloprid and two area(Chuncheon,Wonju) has the lowest acaricidal effect to Permethrin. Futher study will need to compare the acaricidal efficacy of theremaining seven province.

Aedes albopictus (Skuse) has been involved as the potential vector of imported zika virus disease and dengue fever throughout Republic of Korea. It has been reported that the successful introduction of a life-shortening strain of Wolbachia into Ae. albopictus halves adult lifespan and also directly inhibits the ability of a range of pathogens to infect this mosquito species. In our previous studies, Ae. albopictus collected from field was naturally infected by two strains of Wolbachia (wAlbA and wAlbB). However, virus regulation of two Wolbachia strains in Ae. albopictus have not been assessed, yet. In our studies, the two Wolbachia strains in about 20% among Ae. albopictus were removed for the virus regulation test using tetracycline. In this presentation, the detailed results and methods are introduced.

Anopheles sinensis is an important vector for Plasmodium vivax and thus has been targeted with organophosphates in Republic of Korea. Using the direct contact mortality bioassay, two field populations of An. sinensis from Paju-si and Yeoncheon-gun were characterized for their resistance to organophosphats with RR ratio values (Resistant ratio to imidacloprid) of 446.9 to 756.3 folds and 502.1 to 861.7 folds, respectively. Genomic DNA was used for Allele-specific PCR (AS-PCR) genotyping of the acethylcholine esterase to detect Gly119Ser mutations. The homozygous susceptible Ser/Ser genotype in Paju-si and Yeoncheon-gun was 20.0% and 20.9% and the resistance genotypes were 80.0% and 79.1%, respectively. The homozygous Gly/Ser resistance genotype was the most prevalent as 60.7% in Paju-si and 41.9% in Yeoncheon-gun. Hence, this study suggests that malaria vector control programs should be prepared for the management of organophosphate insecticide resistance.