Publications (97)92.34 Total impact
-
Article: Anopheline fauna and incriminatory malaria vectors in malaria endemic areas on Lombok Island, Indonesia
[show abstract] [hide abstract]
ABSTRACT: A systematic mosquito collection was carried out for 3 years from November 2001 to September 2004 in western Lombok Island, Indonesia to clarify Anopheles fauna, and to confirm vector species in malaria endemic areas. Adult mosquitoes were collected at 14 sites in the study area by using double-walled mesh nets with human or cow bait. A total of 11 species were encountered. Anopheles vagus was the most predominant. The second most abundant species differed among the sub-study areas; An. sundaicus was abundant in the coastal plain area, and An. balabacensis in the mountainous area. Anopheles balabacensis showed high anthropophily and exophagy and An. sundaicus moderate anthropophily and exophagy. Malaria parasite detection from the collected mosquitoes was also carried out through the detection of circumsporozoite protein by the VecTest^ . Fourteen and 4 samples, which were positive for Plasmodium falciparum and P. vivax antigen respectively, were found from An. subpictus, An. sundaicus and An. balabacensis. We conclude that malaria in the coastal plain area is transmitted by An. sundaicus and An. subpictus, whereas An. balabacensis is the primary vector in the mountainous area of Lombok Island 2001年11月から2004年9月までインドネシア・ロンボク島・ムニンティング郡においてマラリア媒介蚊調査を行った.合計11種のハマダラカを沿岸,丘陵地,平地,山間部の異なる4地域で採取した.沿岸と山間部で採取した10種について,Vectestを用いてマラリア原虫抗原検出試験を行った結果,森林部で採取したAn.balabacensis,沿岸部で採取したAn.sundaicusとAn.subpictusから陽性反応が得られた.特にAn.balabacensisから多くの陽性反応を得た.これら3種は屋外吸血性,人嗜好性が認められ,マラリア患者との発生時期や分布地域とも一致したため,マラリア媒介蚊と判断した.ロンボク島でのAn.balabacensisによるマラリア媒介は,本研究が初めて明らかにした -
Article: SEASONAL DENSITY AND MALARIA VECTOR COMPETENCE OF ANOPHELES MINIMUS AND OTHER ANOPHELINES AT A SHALLOW VALLEY IN NORTH THAILAND
[show abstract] [hide abstract]
ABSTRACT: Biting density of anopheline mosquitoes was monitored in both the rainy and dry seasons at 6 outdoor stations in two villages of north Thailand by 3 human and 1 water buffalo bait. A total of 19 Anopheles was collected. The most predominant species were An. vagus and An. annularis. They were followed by An. hyrcanus group, An. minimus, An. aconitus, An. nivipes and An. kochi. The rest species were not abundant. The fauna of Anopheles changed seasonally. An. minimus, An. aconitus and An. barbirostris were abundant in the dry season, while An. maculatus sensu lato, An. kochi, An. tesselatus, An. vagus, An. annularis and An. hyrcanus group were the rainy season Anopheles. The 'crude feeding index' was relatively high in An. maculatus and An. minimus. They were followed by An. tesselatus and An. splendidus, while that of An. vagus and An. kochi was less than 1/10 of An. minimus. An. minimus was regarded as the most important vector. The biting density of An. minimus was higher at the peripheral area of villages with scarce dwellings and rich vegetation. At stations with dense dwellings and adjoining to an open field, the density of An. minimus was low, and the malaria risk was probably higher -
Article: A field evaluation study on the effects of residual spray of Bifenthrin and Deltamethrin on Anopheles minimus population in Mae Hong Son Province, northern Thailand
[show abstract] [hide abstract]
ABSTRACT: A field study was conducted to evaluate the effects of indoor residual house spraying of Bifenthrin and Deltamethrin on malaria vector population of Anopheles minimus s.l., from April 1999 to April 2001 at rural villages in Mae Hong Son province, northern Thailand. Nine villages in Mae Hong Son province were selected for the present study (three villages for control and three villages each for insecticide spray). The residual spray of Bifenthrin (25 mg/m2) showed greater adulticiding effects on An. minimus s.l. population than Deltamethrin (20 mg/m2). In Bifenthrin treated villages, a clear decrease in biting density of An. minimus s.l. was found in human bait collection as well as animal bait collection after the insecticide spray. In all of the three villages, the average density after insecticide spray was significantly lower than that observed before the spray. The effects of Deltamethrin on An. minimus s.l. density was found only in one village out of the three treated villages. A significant decrease in parous rate after insecticide spray was found in all the villages sprayed with Bifenthrin, whereas no significant changes were observed in control villages. The average parous rate in the villages treated with Deltamethrin became significantly higher after the insecticide spray. These results clearly suggested that the residual spray of Bifenthrin (25 mg/m2) was more effective than Deltamethrin (20 mg/m2) -
Article: Pre-and post-prandial mosquito resting behavior around cattle hosts.
[show abstract] [hide abstract]
ABSTRACT: Spatial distribution of mosquitoes around a bovine host was studied in November 1997 in northern Thailand (17°38'N, 99°23'E). Forty bamboo stakes were arranged I m apart. in 4 rays of 10, around a cow tethered in an open field. All mosquitoes found resting on the stakes were collected by aspiration between 7:00 p.m. and I 1:00 p.m., sexed, and identified to species; and feeding status was categorized as fed or unfed. Collections were repeated over 8 nights, with and without the host cow. A total of 1.566 mosquitoes from 25 species (5 genera) was collected Anopheles aconitus Was the most abundant species (643 individuals), followed by An. pediateniatus Culex vishnui, and Cx. pseudovishnui. We found that the number of mosquitoes collected from the stakes was related its the presence of the cow host; the number of mosquitoes collected was unrelated to the compass point location of the bamboo stakes with the exception of Mansonia uniformis; unfed mosquitoes preferred bamboo-stake resting sites that were closer to the host the daily fed to unfed ratio of the dominant species was negatively correlated with the daily total number of mosquitoes collected; and fed and unfed mosquitoes clustered in interspecific heterogeneous groups around the host cow. Cluster analysis separated the species into 2 groups. The 1st consisted of 5 species with higher proportions of fed mosquitoes, whereas the 2nd, represented by 7 species, aggregated around the host within a distance of 1-4 m with lower proportions of fed mosquitoes. The interspecific variation in the distribution of unfed females was presumed to be due to a lack of feeding success. We discuss the significance of prebiting resting. In cases in which large numbers of mosquitoes are present, prebiting resting can be adaptive It avoid host defensive behavior triggered by attacking mosquitoes. 有料公開中 -
Article: A FIELD STUDY ON THE EFFECTS OF RESIDUAL SPRAY OF ENCAPSULATED FENITROTHION ON ANOPHELES MINIMUS POPULATION IN PHARE PROVINCE, NORTHERN THAILAND
[show abstract] [hide abstract]
ABSTRACT: A field study was carried out in 2 villages of Phare Province, Thailand to evaluate effect of the residual spraying of a microcapsulated formulation of 20% fenitrothion (Sumithion 20 MC(R)) on Anopheles minimus populations. In the treatment village, houses were sprayed with 1g/m2 of fenitrothion, except for 2 houses which were selected to spray with 0.5g/m2 of fenitrothion for comparative bio-assay test. The results of bio-assay test showed that mortality of An. minimus was 100% in 1g/m2-30 miniutes until 4 months after the spray. The growth rate of An. minimus population during the first 4 months of the study period in the treatment village was lower than that in the control area. These results suggested that the residual spray of fenitrothion microcapsules at the beginning of the dry season was effective at least for 4 months after the spray and could suppress the density of An. minimus -
Article: SEASONAL ABUNDANCE OF DENGUE VECTORS IN RELATION TO RAINFALL AND PREVALENCE OF BREEDING CONTAINERS IN FIJI, 1981
[show abstract] [hide abstract]
ABSTRACT: 1980年から1981年にかけて，フィジーのAedes aegyptiとAe.pseudoscutellarisの発生状況と発生原因調査を，毎月定期的に実施した。多雨地域に位置する首都スパ市域と周辺の村落部，少雨地域の都市ラウトカの市域とその周辺の村落部の幼虫発生指数を検討した。発生は利用可能な容器の密度に依存すること，容器の密度は降雨量に依存することが確かめられた。降雨への依存程度は，Ae. pseudoscutellarisの方が高かった。発生容器の多寡と多様性は，地域固有の社会経済的機能，住民の生活様式，公共の公衆衛生的サービスの質に左右された。降雨量の多少に拘らず，村落部では空き缶等の小容器とドラム缶の密度が高かった。これはゴミの定期的収拾と，パイプ給水の未実施と関係がある。古タイヤは工場地帯を除けば，地域を問わずまんべんなく分布していた。自然的および人為的要因による幼虫発生容器の存在状況の違いは，両デング熱媒介蚊種が属性として示す産卵選好水域の違いを通して，両種の浸淫度の地域間差異に帰結する。ゴミを定期的に収拾する地域の拡大と古タイヤ対策が，同国におけるデング熱媒介蚊防除対策の要と考えた。 A larval monitoring of dengue vectors, Aedes aegypti and Ae. pseudoscutellaris, was carried out as regularly as possible in several cities of Viti Levu, the main land of Fiji in 1981. Larval indices of both the two vector species were apparently precipitation dependent, and it was due to abundant available breeding containers. Seasonal fluctuation of those indices was more drastic in Ae. pseudoscutellaris than in Ae. aegypti. More breeding containers were found in rural area than in urban area. Performance of regular garbage collection service in urban area could reduce breeding containers for the species effectively. The variety and the density of potential containers were different in rural and urban areas. These differences were also found among industrial, commercial and residential blocks in a city, and were considered to affect species composition of the vectors -
Article: Decrease of vector mosquitoes of bancroftian filariasis in a village on Fukue Island, Nagasaki, southwestern Japan
[show abstract] [hide abstract]
ABSTRACT: In 1994, mosquitoes were collected by the human bait method and by a suction tube at cowsheds in a village, Nagasaki prefecture, where bancroftian filariasis was formerly endemic (microfilaria positive rate was 14.0% in 1961) but all inhabitants became free of microfilariae by the control of vector mosquitoes carried out from 1962 to 1971. The abundance of mosquitoes collected in 1994 was compared with that in 1961 in previously published report. A remarkable decrease of the principal vector mosquito, Culex pipiens pallens, was noted from 1961 to 1994, and it was considered that the risk of filariasis infection became negligible -
Article: An Annotated List of Culicoides Biting Midges in Yaeyama Islands in the Southwestern Part of Japan (Diptera: Ceratopogonidae)
[show abstract] [hide abstract]
ABSTRACT: Species of Culicoides biting midges (Diptera: Ceratopogonidae) in Yaeyama Islands were listed. In total, 36 species were included in the list, in which C. palpifer Das Gupta and Ghosh was new to Japan and C. cylindratus Kitaoka, C. malayae Macfie and C. sasai Kitaoka were new to the islands. Taxonomic and biological notes for some species were also given -
Article: Parous Rate as a Function of Basic Population Parameters of Mosquitoes
[show abstract] [hide abstract]
ABSTRACT: A mathematical formula was derived to describe the parous rate as a function of basic population parameters of mosquitoes. The formula includes 4 parameters, the daily survival rate of adults, the number of gonotrophic cycles per life time, the length of a gonotrophic cycle and the finite rate of population increase. Using the formula, some simulation studies were made to compare the sensitivity of the parous rate to these 4 parameters. The importance of the daily survival rate of adults and the length of a gonotrophic cycle depends largely on the finite rate of population increase. The parous rate is more sensitively influenced by these two parameters when populations are decreasing than when they are stable or increasing. The number of gonotrophic cycles per life time is effective only when it is smaller than 7, therefore, its importance seems to be negligible in most of mosquito species -
Article: A Laboratory Experiment on the Larval Development of Aedes polynesiensis under Different Rearing Conditions
[show abstract] [hide abstract]
ABSTRACT: Larvae of Aedes polynesiensis were reared from hatching to emergence in a laboratory under different conditions of the density, the amount of food and the space. Larval developmental period and mortality were clearly affected by the amount of food per larva. Larval aggregation effect was observed as shortening of larval period and decreasing mortality under the constant amount of food per larva -
Article: Distribution of Mosquitoes on a Hill of Nagasaki City, with Emphasis to the Distance from Human Dwellings
[show abstract] [hide abstract]
ABSTRACT: Mosquito larvae were examined by using an ovitrap and adults by human bait catch from May to August in 1989 at 27 sites from the foot to the top of Konpira Hill of Nagasaki City, ranging from 120 to 320m in altitude. Dominant mosquito species of both larvae and adults were Aedes japonicus, Ae. albopictus and Tripteroides bambusa, but remarkable differences were recognized in distribution among species. Ae. albopictus was abundant near the foot of the hill where human dwellings were located, while Ae. japonicus was rather evenly distributed from the foot to the top and Tr. bambusa was abundant near the top. More abundant Ae. albopictus near the foothill is probably due to a marked feeding preference for man -
Article: Evaluation of effective period of a juvenile hormone mimic, pyriproxyfen, against Aedes albopictus : Preliminary experiments in the laboratory and the field
[show abstract] [hide abstract]
ABSTRACT: Effective period of pyriproxyfen against Aedes albopictus was evaluated in the laboratory and the field. Experimental containers were treated with 3 different concentrations of pyriproxyfen and placed in the laboratory. In the field, the experimental containers were placed for 3 weeks, and then treated with the same concentrations as the laboratory experiment. Pupae were collected and the emergence of adults was examined every 2 weeks for 8 weeks. Pyriproxyfen was more effective in the laboratory than in the field. The change of water amount was one of the important factors determining the efficiency of pyriproxyfen in the field. No significant differences were observed in the number of collected pupae among concentrations in the laboratory, while smaller number of pupae were collected from the higher concentrations in the field. The duration for the complete inhibition of adult emergence at the highest concentration (0.1 ppm) was 4 and 6 weeks in the field and in the laboratory, respectively -
Article: MALARIA ENDEMIC PATTERNS ON LOMBOK AND SUMBAWA ISLANDS, INDONESIA
[show abstract] [hide abstract]
ABSTRACT: 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 -
Article: Vector Mosquitoes of Japanese Encephalitis (Diptera: Culicidae) in Northern Thailand: Seasonal Changes in Larval Community Structure
[show abstract] [hide abstract]
ABSTRACT: Larval mosquito communities in rice fields were examined monthly for 2 years at 3 study areas (15 subareas) near Chiangmai, Thailand. the temporal and spatial variations of community structure were analyzed based on the similarity of species composition among mosquito communities. Subareas were grouped depending on the similarity of the species composition. A large cluster which was composed of several small groups of subareas supporting mosquito communities of a similar species composition was observed in the rainy season. In the subareas of the large cluster, 2 Japanese encephalitis (JE) vector mosquitoes, Culex vishnui THEOBALD and C. tritaeniorhynchus GILES, occupied more than 60% of the mosquito communities, and a large number of JE vectors appeared from the rice fields. In the dry season, the large cluster of subareas disappeared and the species composition of the mosquito community varied greatly among the subareas. The successional change of mosquito colonization and an asynchronous cultivation of rice plants were suggested as important ecological factors related to the development of rice field mosquito communities -
Article: Comparative insecticidal efficacy of a new pyrethroid, metofluthrin, against colonies of Asian Culex quinquefasciatus and Culex pipiens pallens
[show abstract] [hide abstract]
ABSTRACT: Comparative insecticidal efficacy of metofluthrin, a newly synthesized pyrethroid, and other pyrethroids against several colonies of Asian Culex quinquefas-ciatus (from Indonesia, Thailand, Vietnam and Malaysia) was evaluated by topical application. Metofluthrin was the most effective against the four colonies of Cx. quinquefasciatus. The LD50-based relative effective ratio of metofluthrin against d-allethrin was higher in Cx. quinquefasciatus (33.3 to 78.8) than in Cx. pipiens pallens (27.8). The Vietnam colony was the most susceptible among the colonies in the study -
Article: A Field Experiment of the Emergence Inhibition of a Juvenile Hormone Mimic, Pyriproxyfen, Against Aedes albopictus in Nagasaki, Japan
[show abstract] [hide abstract]
ABSTRACT: A field experiment was conducted to examine the duration of complete inhibition of adult emergence of Aedes albopictus at 3 different concentrations of pyriproxyfen (0.1, 1, and 10ppm). Forty plastic containers with 1,000ml of water were placed as ovi-traps at the campus of Nagasaki University School of Medicine on 1 June 1993. Twenty-five ovi-traps were treated with 0.1, 1, and 10ppm of pyriproxyfen and 15 ovi-traps were left without treatment as the control. Pupae of naturally breeding Ae. albopictus were collected from the ovi-traps 3 times a week from June to October and the percentage of adult emergence was examined in the laboratory. The emergence of adults was inhibited completely during the whole study period at the highest concentration of 10ppm, whereas the complete inhibition of emergence was never observed at the lowest concentration of 0.1ppm. The negative correlation between the concentration of pyriproxyfen and the density of puape was observed in the whole experimental period, except the late October. The minimum concentration of pyriproxyfen that results in the complete inhibition of adult emergence of Ae. albopictus during the whole breeding season was estimated around 1ppm in the field conditions in Nagasaki -
Article: A Comparative Study on Life Table Characteristics of Two Strains of Aedes albopictus from Japan and Thailand
[show abstract] [hide abstract]
ABSTRACT: Life tables of two strains of Aedes albopictus originated from Nagasaki, Japan and Chiangmai, Thailand were examined in the laboratory conditions of 27℃, 75% R.H. and 16L:8D. The developmental period (egg to adult) in females of Chiangmai strain tended to be shorter than in those of Nagasaki strain. The body sizes of femals were not significantly different between the two strains. Since females of Nagasaki strain took blood meals more frequently and produced more eggs per blood meal than those of Chiangmai strain, a marked difference was observed in m_x-curve between the two strains. l_x-curve of females in the two strains were similar and no significant differences were observed in the longevity of the females. Nagasaki strain showed larger values of the net reproductive rate and the intrinsic rate of increase, and longer mean generation time than Chiangmai strain -
Article: Field trial of the spatial repellency of metofluthrin-impregnated plastic strip against mosquitoes in shelters without walls (Beruga) in Lombok, Indonesia
[show abstract] [hide abstract]
ABSTRACT: Field trials on the spatial repellency of metofluthrin-impregnated plastic strips for mosquitoes present in shelters without walls (beruga) were carried out in Lombok, Indonesia. A major reduction in the incidence of human biting by Culex quinquefasciatus was achieved, and the use of two strips per beruga repelled >60% of the mosquitoes for at least 11 wk while four strips repelled >60% of the mosquitoes for more than 15 weeks. The technique was found to be a practical long-term solution for the prevention of mosquito bites without using electricity or heat to evaporate the metofluthrin -
Article: Effectiveness in controlling mosquitoes with EcoBio-Block S - a novel integrated water purifying concrete block formulation combined with the insect growth regulator pyriproxyfen
[show abstract] [hide abstract]
ABSTRACT: EcoBio-Block S, a novel controlled release system (CRS) for the insect growth regulator pyriproxyfen, uses a water-purifying concrete block system (EcoBio-Block) composed of a porous volcanic rock and cement, and it incorporates the aerobic bacterial groups of Bacillus subtilis nallo. EcoBio-Block S showed high inhibitory activity against mosquito emergence as well as a water-purifying effect. Chemical analysis and bioassay showed that EcoBio-Block S provides a high-performance CRS that controls the release of pyriproxyfen at low levels according to "zero order kinetics." -
Article: Spatial repellency of metofluthrin-impregnated multilayer paper strip against Aedes albopictus under outdoor conditions, Nagasaki, Japan
[show abstract] [hide abstract]
ABSTRACT: Spatial repellency of a new device in which metofluthrin, a newly synthesized pyrethroid, is impregnated into a multilayer paper strip, against Aedes albopictus was evaluated under outdoor conditions. High spatial repellency (>80%) with the metofluthrin-impregnated (200 mg) device lasted for more than 6 weeks, while the repellency with the same device impregnated with the same amount of transfluthrin declined within 5 weeks after treatment
Top co-authors
Top Journals
Institutions
-
2004–2012
-
Nagasaki University
Nagasaki-shi, Nagasaki-ken, Japan -
Ministry of Public Health, Thailand
- Department of Disease Control
Bangkok, Bangkok, Thailand
-
-
2005–2009
-
Chiang Mai University
- Department of Parasitology
Chiang Mai, Chiang Mai Province, Thailand
-
-
2008
-
National Institute of Hygiene and Epidemiology
Hà Nội, Thu Do Ha Noi, Vietnam
-
-
2004–2007
-
University of Nagasaki
- Department of Vector Ecology and Environment
Nagasaki-shi, Nagasaki-ken, Japan
-
-
2002
-
NHO Nagasaki Medical Center
Nagasaki-shi, Nagasaki-ken, Japan
-
