Dengue is the most important arboviral disease in tropical and subtropical areas where 2.5 billion people are at risk of infection. Aedes albopictus will be a major vector transmitting dengue virus in Korea, where this virus overseas inflow is possible. We collected mosquitoes in Jeju, Busan, Gunsan, and Incheon using BG sentinel trap from April to October in 2016. Collected mosquitoes were conducted virus detection using real-time PCR method and analysis bloodmeal source of Ae. albopictus. A total of 15 species comprising 7 genera were identified and 4,854 female mosquitoes collected. The most dominant species ratio (SR) was 52.9% (Culex pippins complex) followed by 20.3% (Ae. albopictus), 10.8% (Ae. vexans nipponi) and Ochlerotatus dorsalis (3.8%). Dengue virus was not detected. Bloodmeal source of Ae. albopictus was mammals (80.9%) followed by birds (18.6) and amphibians (0.5).

The purpose of this monitoring is to survey the geographical distribution of tick species using dry ice bait traps and flagging methods at each ten provinces (GangwonⅠ,GangwonⅡ, Gyeonggi, Chungbuk, Chungnam, Gyeongbuk, Gyeongnam, Jeonbuk, Jeonnam and Jeju area) and one Metropolitan area in the Republic of Korea for eight months from April through November, 2016. A total of 65,339 ixodid ticks (8,200 females, 1,988 males, 31,453 nymphs and 23,698 larvae) was collected, belonging to three genera (Haemaphysalis, Ixodes and Amblyomma). Haemaphysalis longicornis was the most commonly collected species, which is represented for 96.88% of all the collected ticks and followed by H. flava (2.69%), I. nipponensis (0.35%), A. testudinarium (0.05%) and H. japonica (0.03%) in the Republic of Korea for the study period. Haemaphysalis longicornis was a dominant species observed in these eleven areas.

We performed a survey for flavivirus infection and distribution of Aedes albopictus that known as Zika and Dengue virus vector using black–light trap and BG-sentinel trap around urban area in Korea. Mosquitoes were collected in 27 cities during March to November (twice a month) year 2016. Total numbers of mosquitoes collected 102,102 including 19 species 8 genera during collecting period. Total 21,467 Ae. albopictus was collected that 20,961(24.3%) by BG-sentinel trap and 506 (3.2%) by Black-light trap in urban area. Trap index(trap/night) of Ae. albopictus was showed highest in Hamyang (TI:992.3) and lowest in Taebaek (TI:0.3) there was only collected by Black-light trap. A total of 894 pools from all collecting Ae. albopictus were performed a Flavivirus detection. Flavivirus was not detected during study period. This study may provide basic information for surveillance of imported diseases (include Zika virus) and vectors in Korea.

West Nile Virus (WNV) is transmitted by infected mosquitoes. Vector mosquitoes usually acquire these pathogens from feeding on an infected host, and transmit the pathogens to a naive host during feeding events. To understand the virus transmission dynamics and to survey WNV throughout country, the present study has been conducted. We collected mosquitoes in Jeju, Busan, Gunsan, and Incheon using CDC light trap and BG Sentinel trap from April to October in 2016. Among collected mosquitoes, blood-fed mosquitoes were conducted blood meal identification assay and the other mosquitoes were subjected to virus detection using real-time PCR method. A total of 29,603 mosquitoes representing 8 genera and 19 species were collected. The most dominant species was Culex pippins complex (35.0%) followed by Cx. bitaeniorhynchus (12.2%), Armigeres subalbatus (11.2%), Aedes albopictus (10.8%), Ae. vexans nipponii (10.3%), and Ochlerotatus dorsalis (8.4%). The blood meal source were of mammal (70.4%), birds (29.0%) and amphibian (0.6%). WNV was not detected in any mosquitoes.

The Ixodid ticks has been suspected to be the vector of severe fever with thrombocytopenia syndrome virus (SFTSV) in Korea. In order to confirm transovarial transmission of Ixodid ticks, a total of blood fed 284 ticks were collected from six host animals. They were identified as 3 genera and 4 species, Haemaphysalis longicornis (97.2%), H. flava (0.7%), Ixodes nipponensis (1.8%) and Amblyomma testudinarium (0.4%). Among them, 192 female adults hatched their eggs successfully. Our results showed a high prevalence of SFTSV among collected ticks (3.1%, 6/192 ticks), and we detected SFTSV from their larvae. This result suggests that the parent generation of H. longicornis can transmit SFTSV transovarially into their F1 progeny and H. longicornis might be one of major vectors of SFTSV in Korea.

Severe fever with thrombocytopenia syndrome (SFTS) is an emerging tick-borne zoonosis and SFTS virus is transmitted to humans by tick bites. The aim of this study was to monitor tick population and its SFTS virus infection. During March 2014 to October 2015, ticks were monthly sampled using dry-ice bait trap and flag method from 4 collecting points in Boeun-gun. A total of 16,500 ticks, including 14,646 Haemaphysalis longicornis (88.7%), 1,825 H. flava (11.1%), and 29 Ixodes nipponensis (0.2%), were collected. Ticks were pooled (5,156 ticks in 456 pools) and tested by RT-PCR and nested PCR and the minimum infection rate of ticks was 0.27% (14 pools) consisting of 0.13% H. longicornis (6 pools), 1.19% H. flava (8 pools). This annual surveillance study will be needed for long-term monitoring of ixodid ticks in Korea.

The geographical distribution of ixodid ticks in were surveyed at 10 areas from April to November 2015. We investigated tick distribution using dry ice bait trap and flagging method as a part of disease vector monitoring in Korea. As a result, ticks collected 29,992 ixodid ticks with 3 genera, 7 species. Among them, Genus Haemaphysalis, Ixodes and Amblyomma accounted for 29,751 (99.2%), 223 (0.7%) and 18 (0.1%). Haemaphysalis longicornis was accounted for 88.9%, which has become the dominant species. Some species, such as H. japonica and Ixodes persulcatus were only collected Gangwon area. Metropolitan area had the highest population of ticks 6,540 (21.8%), Chungbuk area was next 5,049 (16.8%). In environmental distribution, Genus Haemaphysalis was highly collected in grassland site (32.1%) and Genus Ixodes was highly collected in coniferous forest site (43.5%). Upon analysis of the monthly distribution, H. longicornis, the dominant species, was highly collected at nymph stage in May, and its larva was highly collected in September. These studies may provide important information for control and management of tick in Korea.

We conducted a investigation for distribution and flavivirus infection of mosquitoes using black –light trap around Incheon international airport there was possible overseas inflow caused by global warming in Korea. Mosquitoes were collected once a week April to October during 6 years (2009~2015). The numbers of mosquitoes collected in Oseong and Eurwang mountain were 8,969 and 7,978 including 12 species 7 genera respectively during collecting period. Culex pipiens complex was dominant species in two collecting area as 4,621(51.5%) in Oseong and 3,761(47.1%) in Eurwang mountain. A total of 16 pools from 88 Aedes albopictus were performed a Dengue virus (DENV) detection and total 628 pools from 11,146 other mosquitoes performed a West nile virus (WNV) detection. Flavivirus was not detected during study period. This study may provide basic information for surveillance of imported diseases and vectors in Korea.

As the malaria surveillance agency, the Korean Center for Control and Prevention (KCDC) has been monitoring malaria vector mosquito density and Plasmodium vivax infection since 2009. Anopheline mosquitoes were collected at 35 sites in Incheon, northern Gyeonggi and northern Gangwon Province using black light trap daily from April to October 2015. P. vivax infection of malaria vector mosquitoes tested by polymerase chain reaction (PCR). In 2015, a total of 57,926 malaria vector mosquitoes were collected among 138,119 mosquitoes. Three P. vivax positive pools were detected among 1,556 pools (13,745 individuals) and its minimum infection rate was 0.22. According to the monitoring result of malaria vector mosquitoes, early summer (June-July) could be an appropriate time for a malaria elimination campaign until September.

This study was performed to recognize species composition of Anopheline mosquitoes and infection rates of Plasmodium vivax in the northern part of South Korea. Adult mosquitoes were collected at 9 Republic of Korea (ROK) army installations in northern part of Geyonggi Province near the demilitarized zone (DMZ) using black light traps. Polymerase chain reaction (PCR) was used to identify collected Anopheline specimens and detect P. vivax from them. During June to August 2016, total 481 anopheline mosquitoes were collected and identified. Anopheles kleini was the most frequently collected (56.1%), and followed by An. pullus (16.6%), An. sinensis (16.2%), An. belenrae (7.5%) and An. lesteri (1.5%). 6 pools (4.0%) were positive for P. vivax among 150 pools. The minimum infection rates (MIR) was 1.24. Our ongoing study will provide a meaningful data for the effective malaria elimination strategy.

A surveillance of chigger mites was performed to monitor the incidence of scrub typhus vectors at 5 environmental collection points of 3 locations (Muju, Namwon and Gimge) from April 2016 in Jeollabuk-Do, Korea. During the surveillance period, 3,292 chigger mites were collected and the predominant species were Leptotrombidium pallidum (42.9%). The high environmental collecting rates were recorded at reservoir bank (31.6%) and grassfield (29.7%). We detected Orientia tsutsugamushi from the samples collected in Jeollabuk-Do using nested polymerase chain reaction. The specific DNA of O. tsutsugamushi were detected in 11 pools among total 119 pools and its minimum positive rate was 0.35%. In order to clarify the relationship between chigger mites and scrub typhus cases, further survey will be needed.

Dengue is the most important arboviral human infection worldwide. Approximately 50-100 million cases occur annually and more than 2.5 billion people are at risk of infection. This virus is possibility of overseas inflow to be high in Korea. We collected mosquitoes in Jeju, Busan, Gunsan, and Incheon using BG Sentinel trap from April to August in 2016. Collected mosquitoes were conducted virus detection using real-time PCR method. A total of 15 species comprising 7 genera were identified and 3,696 female mosquitoes collected. The most dominant species ratio (SR) was 49.4% (Culex pippins complex) followed by 21.8% (Aedes albopictus), 13.6% (Ae. vexans) and Ochlerotatus dorsalis (4.8%). Dengue virus was not detected in any mosquitoes until now.

West Nile Fever is one of most serious disease spreading throughout world since 1990. West Nile Virus (WNV) is transmitted by infected mosquitoes. The possibility of overseas inflow of this virus seems to be high in Korea. To know the WNV infection of mosquitoes, we collected mosquitoes in Jeju, Busan, Gunsan, and Incheon using CDC light trap and BG Sentinel trap from April to August in 2016. Collected mosquitoes were conducted virus detection using real-time PCR method. A total of 22,632 mosquitoes representing 9 genera and 18 species were collected. The most dominant species was Culex pippins complex (36%) followed by Aedes vexans (13%), Ae. albopictus (10%) and Ochlerotatus koreicus (10%). WNV was not detected in any mosquitoes until now.

Ixodid ticks are notorious as the vector of severe fever with thrombocytopenia syndrome virus (SFTSV) in Korea. To confirm the transovarial transmission of SFTSV, we collected blood-fed adult ticks from animals in SFTS case reported area of Jeju island in 2015. A total of 476 ticks were collected from four host animal species, horse (81.3%), dog (9.0%), roe deer (7.1%) and wild boar (2.5%). They were identified as 1 genus and 2 species, Haemaphysalis longicornis (87.8%) and H. flava (12.2%). Among them, 131 adults hatched their eggs successfully. The body weight of females was highly correlated with the number of egg masses laid (P < 0.05). We confirmed that one adult H. flava was infected with SFTSV and its infection rate was 0.77%. The eggs of the SFTSV-infected adults also were infected with SFTSV and its transovarial transmission was confirmed. This result suggests that the parent generation of H. flava could transmit SFTSV transovarially into their F1 progeny and H. flava might be one of major vectors of SFTSV in Korea.

We investigated the distribution of ixodid ticks in severe fever with thrombocytopenia syndrome (SFTS) case reported areas using flagging method from May to November 2014 in Korea. We collected 13,471 ixodid ticks with 2 genera and 3 species. Among them, Genus Haemaphysalis and Ixodes accounted for 99.9% (13,455) and 0.1% (16), respectively. Genus Haemaphysalis consisted of 2 species, H. longicornis (96.2%) and H. flava (3.7%). I. nipponensis was only collected in Genus Ixodes. H. longicornis was the dominant species (over 90%) in most study areas. Ixodid ticks were evenly distributed at various environmental sites, such as residences, hills, grassfields, fields, graves, copses, other sites. The further study on SFTSV infection in ixodid ticks will be needed.

A surveillance of chigger mites was performed to monitor the incidence of scrub typhus vectors at 4 environmental collection points of 6 locations from September to November 2014 in Korea. During the survey period, 420 chigger mites were collected and the dominant species was Leptotrombidium scutellare (42.6%). The first appearance of chigger mite was at 37th week (9.3.-9.10.) and the collected numbers of chigger mites was the highest at 43rd week (10.17.-10.23.). In Goryeong-gun, 299 chigger mites were collected, whereas 5 chigger mites were collected In Yesan-gun. The high environmental collecting rates were recorded at rice field (56%) and waterway (20%). The annually collected numbers (2012-2014) of chigger mites were compared with the average temperatures in August. This result suggests that the average temperature in August might be related with the annual incidence of scrub typhus vectors in Korea. However, the relationship between climate factors and the density of chigger mites needs to be studied by long-term periodical surveillance.

Trombiculid mites are known to be the vector of scrub typhus by transmitting rickettsial pathogen, Orientia tsutsugamushi, to human. In this study, we tried to establish a monitoring system for trombiculid mites using chigger mite collecting traps instead of the conventional rodent-capture method. For selection of collecting points, 10 environmental points were chosen from three regions (Taean, Jinan and Chungju) and two field collections were performed in spring (March-May) and autumn (October-November) seasons from 2013 to 2014. Among 10 environmental points, waterway (37.9%), grass field (28.0%), rice field and field near mountain side (11.4%) and reservoir/wet field (7.3%) showed high collecting rates and they should be included for the representative collecting points for surveillance using chigger mite collecting trap. In order to test the possibility that the dried chigger mites from collecting trap can be used for detection of O. tsutsugamushi, we pooled 30, 10 and 5 chigger mites separately and performed the nested PCR. The infection of O. tsutsugamushi was successfully detected from 5 chigger mites pooling sample. This study shows that chigger mite collecting trap could be an alternative method for monitoring system of scrub typhus vectors.

Bacillus thuringiensis (Bt) is a gram-positive and spore-forming bacterium that produces parasporal inclusions containing Cry and Cyt proteins during sporulation. These inclusions or proteins are highly toxic to lepidopteran, dipteran, coleopteran larvae, and nematodes. Because of their selectable specificity and safety to non-target organisms and environment, Bt is considered as a valuable and safe alternative to chemical pesticides for eradication of insect pests. Bt biopesticide products has been commercialized and used very widely and successfully in agriculture, forestry and medical care markets since 1930s. In Korea, the screening for isolation of new Bt strains such as Bt Nt0423 (Tobbagi) and Bt GB-413 (Solbichae) have been performed and their commercial products were launched in agricultural markets. In terms of public health, mosquito larvicidal products made by Bt subsp. israelensis have been registered by Korean ministry of food and drug safety and used since 1995. Recently, a new mosquitocidal serovar (H3a3b3d), Bt subsp. mogi was isolated and its molecular characteristics were analyzed. In our opinion, Bt biopesticides might be still an effective and safe tool for insect pest control in agriculture and public health. Key words: Bacillus thuringiensis, biopesticide, Bt subsp. israelensis, mosqui