Elevational Distribution of the Asian Tiger Mosquito, Aedes Albopictus, in the Inland Mountain Area of Nagano and Yamanashi Prefectures, Japan
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Journal of the American Mosquito Control Association, 36(1):1–10, 2020 Copyright Ó 2020 by The American Mosquito Control Association, Inc. ELEVATIONAL DISTRIBUTION OF THE ASIAN TIGER MOSQUITO, AEDES ALBOPICTUS, IN THE INLAND MOUNTAIN AREA OF NAGANO AND YAMANASHI PREFECTURES, JAPAN 1 2 2 2 2 KIMIO HIRABAYASHI, NAOKO NIHEI, MUTSUO KOBAYASHI, YOSHIO TSUDA AND KYOKO SAWABE ABSTRACT. Nagano and Yamanashi prefectures of Japan comprise an inland mountain area that extends widely north and south, with elevation varying greatly by location. Mosquitoes transmitting infectious disease have a diversity of habitats in Nagano and Yamanashi, and many species can be expected there. However, there have been few reports on mosquito fauna; in particular, little information is available on mosquitoes such as Aedes albopictus. The mosquito fauna was investigated to clarify their elevational distribution ranging from 317 to 1,534 m, focusing especially on Ae. albopictus, in 24 areas in Nagano and Yamanashi prefectures from July to September in 2012–16. Downloaded from http://meridian.allenpress.com/jamca/article-pdf/36/1/1/2525805/19-6902_1.pdf by guest on 29 September 2021 Adult mosquitoes were collected using the Centers for Disease Control and Prevention traps in each area, in addition to larval mosquito collections at several temple and shrine precincts in each area. At sites where elevations were .800 m (14 sites), no adult Ae. albopictus were captured. In addition, larval Ae. albopictus were not collected at elevations .728 m (15 sites). Aedes albopictus was captured at 20 other sites (annual mean air temperature ranged from 9.4 to 15.28C, July–September mean air temperature ranged from 19.9 to 25.08C). KEY WORDS Annual mean air temperature, Centers for Disease Control and Prevention trap, elevation, habitat, larval survey INTRODUCTION including disease vectors, e.g., Ae. albopictus (Kurihara et al. 2000; Shirai et al. 2002; Takahashi Aedes albopictus (Skuse) ranks second only to et al. 2005; Takahashi 2012, 2013). Aedes aegypti (L.) in medical importance as a vector The mosquito fauna was investigated to clarify of dengue virus (Knudsen 1995, Knudsen et al. their elevational distributions, focusing especially on 1996). Dengue fever affects .2.5 billion people Ae. albopictus, in 24 areas in Nagano and Yamanashi living in urban and suburban environments in .100 prefectures from July to September in 2012–16. countries in tropical and subtropical regions around the world (European Centre for Disease Prevention and Control 2009, Guzman et al. 2010). According to MATERIALS AND METHODS Hotta (1953), Japan experienced endemic dengue outbreaks in several coastal cities in 1942–45. Mosquito surveys were conducted from the end of Although dengue hemorrhagic fever has not been July to early September 2012–14 in 17 areas, prevalent in Japan for the past 50 years, the including 11 cities, 3 towns, 5 villages, and 2 possibility of dengue outbreaks exists due to the highlands, in Nagano Prefecture (Fig. 1 and Table distribution of Ae. albopictus throughout much of 1). Both adults and larvae were collected at a total of Japan (Hotta 1998). Vector control is an essential 91 sampling sites, e.g., temples and shrines. Table 1 measure for controlling viral disease outbreaks, and lists the study areas, sampling sites, elevations (from collecting information about the distribution and 317 to 1,534 m), and environmental conditions ecology of vectors contributes to the development of (annual mean air temperature and July–September effective vector control methods. mean air temperature for each area over 10 years from Nagano and Yamanashi prefectures in Japan 2004 to 2013) of the mosquito collection areas and comprise an inland mountain area that extends surveillance periods/days. The latitude ranged from 35830021.2400 Nto36855028.2300 N, and the longitude widely north and south, with an elevation that varies 0 00 0 00 greatly by location. There are a diversity of larval ranged from 137848 46.32 Eto138838 10.77 E. and adult mosquito habitats in Nagano and Yamana- In Yamanashi Prefecture, mosquito surveillance shi, and many species, including vectors of human was conducted from the end of August to early pathogens, can be expected to be there (Kamimura September of 2015 and 2016 in 7 areas, including 7 1968, Saito 1968, Uchikawa 1977). However, there cities and 3 towns (Fig. 1 and Table 2). Both adults have been few reports on mosquito fauna in that area, and larvae were collected at a total of 26 sampling sites, including temples and shrines. Table 2 lists the 1 Department of Applied Biology, Faculty of Textile study areas, sampling sites, elevations (from 164 to Science and Technology, Shinshu University, 3-15-1, 974 m), and environmental conditions (annual mean Tokida, Ueda City, Nagano Prefecture, 386-8567, Japan. air temperature and July–September mean air 2 Department of Medical Entomology, National Insti- temperature for each area over 10 years from 2007 tute of Infectious Diseases, 1-23-1, Toyama, Shinjuki-ku, to 2016) of the mosquito collection areas and Tokyo, 162-8640, Japan. surveillance periods/days. The latitude ranged from 1 2 JOURNAL OF THE AMERICAN MOSQUITO CONTROL ASSOCIATION VOL. 36, NO.1 Downloaded from http://meridian.allenpress.com/jamca/article-pdf/36/1/1/2525805/19-6902_1.pdf by guest on 29 September 2021 Fig. 1. Distribution of the 24 survey sites in Nagano and Yamanashi prefectures. 35817041.5700 Nto35852008.8900 N, and the longitude adults were provided a 5% sugar solution and then ranged from 138818007.5400 E to 138847037.3600 E. removed the following day when they were killed by Mosquitoes were collected in the Centers for low temperature (À108C) in a freezer and then Disease Control and Prevention (CDC) traps (no light identified to species as described above. source) baited with dry ice and operated over 24 h. Mosquitoes were collected the following morning RESULTS and placed in a cooler and then transported to our laboratory where they were killed by low temperature A total of 324 individual Ae. albopictus (139 adult (À108C) in a freezer, and then identified morpholog- mosquitoes from CDC traps and 185 individuals ically to species or species group (Tanaka et al. from larvae) were collected in Nagano Prefecture 1979). (Table 1). Although Ae. albopictus was not collected Larval collection sites were selected from each in the Kamikochi area (elevation 1,534 m, annual sampling area. Larvae were collected at 54 sites (128 mean air temperature 5.58C, July–September mean water samples) in Nagano Prefecture and 23 sites (64 air temperature 17.48C), Sugadaira area (1,253 m, water samples) in Yamanashi Prefecture. Various 6.68C, 17.78C), or Karuizawa area (999 m, 8.68C, kinds of containers, e.g., flower vases in graveyards 18.88C), it was captured in the other 14 areas in of Buddhist temples, stone washbasins in shrines, Nagano Prefecture. A large number of adult Ae. used tires stacked in backyards or along roadsides, albopictus were collected from the Iida area, with a used cans or plastic containers, and bamboo stumps, total of 49 individuals and an average of 7.0 were examined for larvae, which were removed using individuals/night/trap, followed by the Ueda area, a glass pipette and then transferred to small with a total of 14 individuals (only 1 site and 1 night). polypropylene bottles (approximately 100-ml vol- A large number of larval Ae. albopictus were ume). They were transported to our laboratory and collected from the Matsumoto area, with a total of maintained at 25 6 28C. Larvae were transferred to a 84 individuals and an average 3.8 individuals/water rearing plastic bottle (approximately 9 cm diam by samples, followed by the Ueda area with a total of 58 10 cm deep) and reared to adult stage. Emerged individuals (mean 2.2/site). 1 M Table 1. Environmental conditions of Aedes albopictus collection sites in Nagano Prefecture, Japan. ARCH 10-year annual Elevation mean AT (6 SD)2; Sampling days of adult collection Sampling day of larval collection Total no. Ae. albopictus 2020 Sampling site (m) Jul.–Sep. mean AT (8C) by CDC trap(s) (water samples) (adults, larvae) Nozawaonsen 5763 10.2 (6 0.7); 21.6 Akataki Shrine 502 Sep. 3–4, 2014 Sep. 3, 2014 (2) 0 (0, 0) Akiba Shrine 601 Sep. 3–4, 2014 Sep. 3, 2014 (1) 0 (0, 0) Kenmeiji Temple 609 Sep. 3–4, 2014 Sep. 3, 2014 (2) 3 (0, 3) Subtotal 3 sites (3 nights); avg. 0 ind./ 3 sites (5 water samples) 3 (0, 3) night by CDC Iiyama 3133 11.5 (6 0.4); 22.6 Hongakuji Temple 317 Sep. 3–4, 2014 Sep. 3, 2014 (1) 3 (3, 0) E Seikeiji Temple 319 Sep. 3–4, 2014 Sep. 3, 2014 (3) 3 (2, 1) LEVATIONAL Korenji Temple 336 Sep. 3–4, 2014 Sep. 3, 2014 (6) 10 (6, 4) Eiganji Temple 329 Sep. 3–4, 2014 Sep. 3, 2014 (4) 3 (0, 3) Subtotal 4 sites (4 nights); avg. 2.8 ind./ 4 sites (14 water samples) 19 (11, 8) night by CDC D Kijimadaira None ISTRIBUTION OF Jorenji Temple 332 Sep. 3–4, 2014 Sep. 3, 2014 (1) 9 (8, 1) Kannonji Temple 328 Sep. 3–4, 2014 Sep. 3, 2014 (2) 4 (4, 0) Subtotal 2 sites (2 nights); avg. 6 ind./ 2 sites (3 water samples) 13 (12, 1) night by CDC Shinanomachi 6853 9.5 (6 0.3); 20.2 A Myosenji Temple 693 Sep. 3–4, 2014 Sep. 3, 2014 (6) 11 (5, 6) E . Furuma Shrine 662 Sep. 3–4, 2014 Sep. 3, 2014 (2) 3 (2, 1) ALBOPICTUS Suwa Shrine 674 Sep. 3–4, 2014 0 (0, —) Subtotal 3 sites (3 nights); avg.