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Background In Hokkaido, northern island of Japan, at least seven cases of falciparum malaria were reported by 1951. A survey conducted at that time was unsuccessful in implicating any mosquito species as the possible vector. Although active anopheline mosquito surveillance continued until the middle of the 1980s, there is very limited information on their current status and distribution in Japan. Therefore, this study is an update on the current status and distribution of anopheline mosquitoes in Hokkaido based on a 15-year entomological surveillance between 2001 and 2015. Methods A survey of mosquitoes was conducted at 22 sites in Hokkaido, Japan, from 2001 to 2015. Adult mosquitoes were collected from cowsheds, lakesides, shrubs, and habitats ranging from open grassland to coniferous forest using a Centers for Disease Control and Prevention (CDC) miniature light trap enhanced with dry ice, aspirators, and sweeping nets. Larvae were collected from lakes, ponds, swamps, stagnant and flowing rivers, and paddy fields. All specimens were morphologically identified and subjected to polymerase chain reaction (PCR)-based sequence analysis of the internal transcribed spacer 2 ( ITS2) region of rDNA. Phylogenetic trees were reconstructed using the neighbor-joining method with the Kimura 2-parameter model on MEGA X version 10.2.2. Results A total of 46 anopheline specimens were used for the phylogenetic analysis. During the survey, a new member of the Anopheles hyrcanus group, An. belenrae, was discovered in eastern Hokkaido in 2004. Anopheles belenrae has since then been consistently found and confirmed to inhabit only this area of Japan. Four members of the An. hyrcanus group, namely An. belenrae, An. engarensis, An. lesteri, and An. sineroides, have been found in Hokkaido. The results also suggest that An. sinensis, formerly a dominant species throughout Japan, has become a rarely found species, at least currently in Hokkaido. Conclusion The updated distribution of anopheline mosquitoes in Hokkaido, Japan, showed considerable differences from that observed in previous surveys conducted from 1969 to 1984. In particular, areas where An. sinensis was previously distributed may have been greatly reduced in Hokkaido. The phylogenetic analysis revealed a novel An. hyrcanus group member identified as An. belenrae, described in South Korea in 2005. It is interesting that An. belenrae was confirmed to inhabit only eastern Hokkaido, Japan. Graphical abstract

Introduction of exotic diseases vectors into a new habitat can drastically change the local epidemiological situation. During 2012—2015, larvae and an adult of the yellow-fever mosquito,Aedes aegypti, were captured alive in two international airports serving to the Greater Tokyo Area, Japan. Because this species does not naturally distribute in this country, those mosquitoes were considered to be introduced from overseaviaair-transportation. To infer the places of origin of those mosquitoes, we genotyped 12 microsatellite loci for which the most comprehensive population genetic reference is available. Although clustering by Bayesian and multivariate methods both suggested all those airport mosquitoes belong to Asia/Pacific population, they were not clustered into a single population. Also, there was variation in mitochondrialCox1haplotypes among mosquitoes collected in different incidents of discovery which indicated the existence of multiple maternal origins. Whereas we conclude there is little evidence to support overwintering ofAe. aegyptiin the airports in this study, special attention is still desired to prevent the invasion of this prominent arbovirus vector.

We found a species of Lutzia Theobald (1903) (Diptera: Culicidae) in Chiang Mai Province and other provinces in northern Thailand which bears morphological and DNA sequence differences from the three species of Lutzia, subgenus Metalutzia Tanaka, previously recorded from Thailand, namely Lt. fuscana (Wiedemann), Lt. halifaxii (Theobald) and Lt. vorax Edwards. The adults of the Chiang Mai form (CM form) have abdominal banding patterns similar to those of Lt. vorax from Japan (which includes the type locality of this species), but differ in having the mediocubital crossvein usually positioned before rather than beyond the radiomedial crossvein. The thoracic and abdominal integument of Lt. vorax larvae is covered with relatively short pointed spicules whereas it is covered by denser, longer and more acutely pointed spicules in the CM form. Some differences are also found in the development of thoracic seta 1-M, and abdominal setae 8-II and 8-III. The pupa of the CM form clearly differs from the pupa of Lt. vorax in having setae 1 and 5 of abdominal segments V and VI branched rather than single. The characters of the wing, larva and pupa of the CM form are similar to those of Lt. fuscana and Lt. halifaxii. However, whereas the phallosome of males of the CM form is similar to males of Lt. vorax and Lt. halifaxii, it is distinct from males of Lt. fuscana. Phylogenetic analysis of mitochondrial cytochrome c oxidase subunits I and II sequences revealed that the CM form falls outside a clade comprised of specimens of Lt. vorax from Japan, Korea, Thailand and Bhutan (Kimura 2-parameter, K2P, genetic distances 3.9–5.6, and 5.1–6.6, respectively). However, the two gene sequences of the CM form are not clearly distinct from clades comprised of sequences from specimens of Lt. fuscana and Lt. halifaxii (K2P 0.2–2.4%). However, based on the combination of morphological and molecular data, the current study provides evidence that the CM form is a previously unrecognized species of the genus Lutzia.

Outbreaks of Culex inatomii occurred widely in disaster areas of the tsunami caused by the Great East Japan earthquake in March 2011. Mosquitoes were collected in southern Miyagi Prefecture and northern Fukushima Prefecture in August and September 2011, respectively. In southern Miyagi Prefecture, the average number of adult Cx. inatomii collected by a suction trap baited with 1 kg of dry ice ranged between 69.3 and 132.8 per day in locations within 2.6 km from the coast in tsunami areas, while no Cx. inatomii individuals were collected 8.3 km from the coast, where seawater did not reach, and which therefore escaped the tsunami disaster. There were many ground pools of brackish water of various sizes, and larvae of Cx. inatomii were collected in 48% and 36% of the pools examined in Miyagi Prefecture and Fukushima Prefecture, respectively. Ecological notes on the larval habitats, biting behavior, seasonal prevalence, and reproduction of Cx. inatomii are presented for reference based on ecological studies conducted in Sakata Wetland, Niigata Prefecture, central Japan, in June and August 2011. Ecological factors relating to the current outbreak and the potential medical importance of Cx. inatomii are discussed.

e Tsunami caused by the Great East Japan Earthquake on 11 March 2011 in north-eastern Japan destroyed urban and rural environments completely, including build- ings, dwellings, roads, bridges, agriculturalelds and natural vegetation. �e aer-eects of the Tsunami on the distribution and abundance of mosquitoes were studied in riceeld ar- eas in Miyagi Prefecture, Japan during June to August 2011. Adult mosquitoes were collected by traps enhanced with 1 kg dry ice and the density was compared between theTsunani� area andNo Tsunamiarea. A total of 6,542 adults of 9 species in 4 genera were collected and the following 4 species were dominant: Culex pipiens pallens, Cx. inatomii , Cx. tritaenio- rhynchus and Aedes albopictus. �e high density and expanded distribution of Cx. inatomii was marked. �e adult density of the former 3 dominant species was signicantly higher in the Tsunami area than No Tsunami area, while Ae. albopictus was signicantly abundant in the No Tsunami area. Ground pools in disaster areas contained brackish water with 0.47 and 0.21% average salinity in June and August 2011, respectively. �e percentage of water sam- ples with mosquito larvae increased from 2.7% in June to 79.5% in August, suggesting the expansion of the larval distribution of Cx. inatomii and Cx. tritaeniorhynchus as well as Anopheles sinensis-group.

A mark-release-recapture of Culex pipiens pallens was conducted in an urban area of Japan during June 26-29, 2007. Larvae naturally occurring in rain gutters were collected and reared to adults in a laboratory. A total of 10,183 emerging female Cx. pipiens pallens of 4-8 days old were marked with fluorescent dye and released from one site. Recapture was made on 4 consecutive days using 41 Centers for Disease Control and Prevention traps with 1 kg of dry ice and human landing collection, and 121 marked females were recaptured. The overall recapture rate was 0.01. The mean distance traveled by the recaptured females was estimated as 470, 287, 326, and 517 m on days 1-4, respectively. The maximum flight distance of host-seeking Cx. pipiens pallens was estimated as 1,217 m based on the relationship between distance from the release site to the collection site and the total number of recaptures/traps. The population size of female Cx. pipiens pallens in the study area was estimated as 100,904 +/- 8,509. The size of operational area for the control of Cx. pipiens pallens in urban area is discussed.

A total of 160 autochthonous dengue cases transmitted by Aedes albopictus were reported between August and October of 2014 in Tokyo Metropolis, Japan. Ae. albopictus is a medically important vector of dengue virus, which has expanded its geographic distribution in temperate regions. Understanding the distribution and biting density of Ae. albopictus during the 2014 dengue outbreak in Tokyo is important to evaluate the epidemic risks of dengue fever in other highly populated cities in Europe and Asia. Of the 160 patients, 134 visited the same park (Yoyogi Park) located in central Tokyo. Mosquitoes infected with dengue virus were collected from this park, suggesting that it was the exclusive location for the transmission of dengue. This study aimed to collect referential data to estimate the transmission threshold of dengue virus in terms of biting density of Ae. albopictus and determined high transmission risk areas of dengue virus in Yoyogi Park and its vicinity. The overall mean density of biting Ae. albopictus (7.13/man/8 min) was sufficiently high for successful transmission of dengue virus, and areas with biting densities higher than the overall mean density were classified as high risk areas for the transmission of dengue virus in Yoyogi Park.

A larval survey of dengue vectors was conducted from July to November 1966 and from May to November 1997 in Chiangmai Province, Thailand. Three villages in urban, transition, and rural areas were selected for the survey to clarify the spatial distribution of Ae. aegypti and Ae. albopictus along an urban-rural ecological gradient. The average number of Ae. aegypti larvae in larvitraps was higher in the urban area than in the rural area, as we expected, whereas the opposite was found for Ae. albopictus, rural areaurban area. A house survey of larvae-inhabiting containers showed significant differences in the number and composition of these containers among the study areas. Significant differences were also found in the average distance between houses, average tree height, and average percentage of vegetation cover for each house. The seasonal pattern of rainfall recorded in each study area did not show great differences among the study areas. The response of Ae. aegypti and Ae. albopictus to the urban-rural gradient is discussed in relation to the possibility of applying geographic information system techniques to plan the control strategy and surveillance of dengue vectors.

Nusa Tengara Barat (NTB) province consists of two main islands, Lombok and Sumbawa, to the east of Bali Island, Indonesia. Most of the area is known to be moderately malaria endemic, but the exact malaria epidemiology has not been elucidated. At least 30 deaths per year are thought to be caused by falciparum malaria in Lombok alone, judging from the hospital data. According to the Gebrak Malaria Team in West Lombok, the annual incidence in the district of West Lombok from 1996 to 1999 was consistently over 40‰. In the present report, we describe the small malaria endemic foci in the West Lombok and Sumbawa districts. Falciparum malaria is predominant over vivax malaria and other types of malaria. There are 11 species of Anopheles vector, but three of these species, An. subpictus, An. maculates and An. barbirostris, are of primary importance in malaria transmission and An. sundaicus and An. aconitus are of secondary importance. Our data from Sekotong, West Lombok, and Sumbawa supported the importance of An. subpictus in coastal areas but suggested the existence of different transmission peaks according to environmental conditions. The usual transmission peak comes in the dry season but is affected by climatic and geographical conditions. Although there were many malaria endemic foci along the coast, the width and grade of the foci varied widely. The presence of malaria endemic foci inland, although likely, has not been definitively reported to date., Tropical Medicine and Health Vol. 33 No. 2, 2005, pp. 105-113

The effects of breeding habitat characteristics on the larval density of Anopheles minimus Theobald were studied in a perennial stream in the foothills of Chiang Mai province, northern Thailand. Data on 41 different variables related to plant cover and stream physical attributes in 200 sections, each 10 m long, were collected along with larval data during the dry and wet seasons of 1998 and 1999. Larval density was significantly higher in the dry season than in the wet season. In the dry season, An. minimus density was negatively correlated with water current velocity, height of aquatic large-leaved plants, and height of riparian small-leaved plants; and positively correlated with the cover of riparian ferns. The dry season prediction model, which explained 51% of the variation of An. minimus, was as follows: ymin = 0.1980–0.1733*water velocity – 0.0317*height of aquatic large-leaved plants – 0.0249*height of riparian small-leaved plants + 0.0192*cover of riparian ferns – 0.0170*height of stream ...

Accumulated anopheline mosquito collection protocols from Chiang Mai province, northern Thailand were compiled and analyzed with the objective to describe and compare the variation in density of malaria vectors between two areas: transmission area (TA) and non-transmission area (NTA), and between two periods: 1977 to 1989 and 1990 to 1999. We hypothesized that the reasons for differences in transmission between areas were caused by higher or increasing densities of malaria vectors in TA and lower or decreasing densities in NTA. We further hypothesized that low vector densities in NTA could be caused by changes in land use, specifically increased landscape diversity and forest fragmentation. Our results indicate that the vector situation in Chiang Mai province is very complex. There were no significant differences in density of the main malaria vectors, Anopheles minimus sensu latu and A. dirus s.l. between areas (TA and NTA). However, the change in density of A. minimus s.l. from the first to the second period was significantly different; TA having an increasing trend and NTA a decreasing trend. Furthermore, the reduction of malaria vectors in the NTA, especially A. minimus s.l. may have been a result of increased landscape diversity and forest fragmentation. There were minor landscape changes in the TA and large landscape changes in the NTA. It was concluded that changes in malaria mosquito densities and land use are important for explaining differences in malaria transmission between areas, but that other factors such as human movement and behavior, and socioeconomic conditions probably also play a role in the transmission of malaria in Chiang Mai province. Die gesammelten Aufzeichnungen zu Anophelesmucken-Erfassungen wurden mit dem Ziel zusammengestellt, die Variation der Dichte der Malariavektoren zwischen zwei Gebieten, einem Ubertragungsgebiet (TA) und einem Nicht-Ubertragungsgebiet (NTA), sowie zwischen den Zeitraumen 1977 bis 1989 und 1990 bis 1999 zu beschreiben und zu vergleichen. Wir stellten die Hypothese auf, dass die Unterschiede in der Ubertragung zwischen den Gebieten durch die hohere oder zunehmende Dichte der Malariavektoren in den TA und niedrigere oder abnehmende Dichte in den NTA verursacht wurden. Wir vermuteten zudem, dass die niedrige Vektorendichte in den NTA durch Veranderungen der Landnutzung, insbesondere durch eine zunehmende Landschaftsdiversitat

WPSAR Vol 5, No 4, 2014 | doi: 10.5365/wpsar.2014.5.3.007 www.wpro.who.int/wpsar 1 a Infectious Disease Surveillance Center, National Institute of Infectious Diseases, Tokyo, Japan. b Department of Virology, National Institute of Infectious Diseases, Tokyo, Japan. c Department of Medical Entomology, National Institute of Infectious Diseases, Tokyo, Japan. Submitted: 26 September 2014; Published: 28 October 2014 doi: 10.5365/wpsar.2014.5.3.007 In late August 2014, three autochthonous dengue cases were reported in Japan. Since then, as of 17 September 2014, a total of 131 autochthonous cases have been confirmed. While cases were reported from throughout Japan, the majority were linked to visiting a large park or its vicinity in Tokyo, and the serotype detected has been serotype 1. We report preliminary findings, along with the public health response activities, of the first documented autochthonous dengue outbreak in Japan in nearly 70 years.

Movement of adult An. minimus Theobald between larval habitats and feeding sites was investigated by mark-release-recapture in March 1993 on Ishigaki Island, Ryukyu Archipelago, Japan. Unfed (998 females) and fed (1,485 females) cohorts from a laboratory colony were marked with different colors of fluorescent dye, and released near Nishihama stream where larvae were abundant. Overall, 42 fed (2.82%) and 13 unfed (1.30%) females were recaptured. Among these, 12 females were recaptured at a cowshed, the nearest blood meal source. Most females in the fed cohort recaptured at the release point had developing or matured ovaries, whereas 55% at the cowshed were parous. The movement of released females from larval habitat to the cowshed for blood feeding indicated a flight distance > 1 km.

We studied the prevalence of avian Plasmodium in 509 mosquitoes of 9 species collected from the Ishigaki and Iriomote islands in the Yaeyama Archipelago, located southwest from the mainland of Japan. Two identical avian Plasmodium lineages were detected from Culex (Culiciomyia) nigropunctatus. Detected lineages were phylogenetically classified into different clade to avian Plasmodium lineages from birds and mosquitoes in the mainland of Japan but identical to a lineage detected from a resident bird, White-breasted Waterken (Amaurornis phoenicurus). This is the first detection of avian Plasmodium DNA from mosquitoes in the Yaeyama Archipelago and suggested that resident birds might have been infected with an avian Plasmodium lineage specific to the studied area and C. nigropunctatus could be the candidate vector mosquito species.

The seasonal prevalence and spatial distribution of mosquitoes were examined as part of an avian malaria study on the oceanic island of Minami-Daito Island, Japan. Because dry ice was not available in this study, yeast-generated CO2 was used to attract biting mosquitoes. Adult mosquitoes were collected biweekly using battery-operated traps enhanced with yeast-generated CO2 and a gravid trap from March 2006 to February 2007. The CO2-baited traps were distributed in 4 different habitats: sugar cane field, forest and vegetation ring, residential area, and swamp area. At 3 collection sites beside sugar cane fields, traps were fixed at 2 different heights (3 and 6 m above the ground). A total of 1,437 mosquitoes of the following 9 species were collected: Culex quinquefasciatus, Aedes albopictus, Coquillettidia sp., Mansonia uniformis, Culex rubithoracis, Armigeres subalbatus, Lutzia fuscanus, Aedes daitensis, and Aedes togoi. Among them, Cx. quinquefasciatus, Ae. albopictus, and Coquillettidia sp. were dominant. The high density and wide distribution of Cx. quinquefasciatus throughout the island suggested the importance of this species as a principal vector of avian malaria on the island.

Species E of the Anopheles minimus sibling species complex is diagnosed and formally named An. yaeyamaensis Somboon & Harbach, sp. n. Information is provided on the morphology, genetics and bionomics of the species, which has a restricted distribution in the Yaeyama and Miyako Islands located at the southern end of the Ryukyu Archipelago of Japan.