This paper focused on malaria epidemic in Ryukyu Islands during World War II with special reference to Yaeyama Islands to prove whether malaria outbreak in Yaeyama in 1945 was unusual, by reanalyzing published data by various researchers and unpublished documents of the U.S. military Government that occupied Ryukyu Islands from 1945 to 1972. The following results were obtained: 1) Outbreak of malaria in the Ryukyu Islands in a period from 1945 to 1947 was caused by great alteration of biologic balances due to military operations by Japanese Army. 2) Compared with those in Miyako and Okinawa Islands, fatality from malaria in Yaeyama in 1945 was extraordinarily high. 3) Forced evacuation of the inhabitants to malaria endemic areas by the Japanese Army caused exceptionally high incidence, mortality and fatality in Yaeyama. 4) Of species of malaria parasites, malignant P, falciparum was predominant in Yeayama. P. vivax was preponderant both in Miyako and Okinawa Islands . 5) In Okinawa Islands, intensive mosquito control measures were initiated by the US Army when they landed the Island in April 1945. But in Miyako and Yaeyama Islands, only partial chemotherapy was administered, not full scale mosquito control activities . In conclusion, unusual outbreak of malaria epidemic in Yaeyama in 1945 was mostly attributed to the forced evacuation of the inhabitants to malaria endemic areas by the Japanese Army.

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A survey was carried out to clarify the mosquito fauna of Yonagunijima located between Iriomote-jima and Taiwan. The mosquitoes were collected five times trom June 1977 through August 1981. In total, 26 species of 9 genera were recorded in the present survey. Among them, following 15 species were recorded for the first time from Yonagunijima : Mimomyia elegans, Mansonia uniformis, Uranotaenia ohamai, Uranotaenia annandalei, Aedes baisasi, Aedes vexans nipponii, Aedes lineatopennis, Culex nigropunctatus, Culex infantulus, Culex bicornutus, Culex pallidothorax, Culex ryukyensis, Culex bitaeniorhynchus, Culex tritaeniorhynchus, and Culex vagans. Tripteroides bambusa yaeyamensis, Aedes riversi, Culex bicornutus and Culex in-fantulus were predominant species and Aedes riversi was the most voracious biter in the forest area. Aedes vexans nipponii, Anopheles sinensis and Culex tritaeniorhynchus were commonly found in paddy fields and swamps, and Aedes albopictus and Culex pipiens quinquefasciatus were predominant in artificial containers and the most voracious biter around dwelling area. The important vector mosquitoes, Anopheles minimus and Aedes aegypti which were recorded before in this island, were not found in the present survey.

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In July and October, 1980,larval collections were carried out to clarify mosquito fauna and their habitats around the human dwellings at Ishigakijima and Iriomotejima. The results are summarized as follows : 1. In total, the following 15 species of 5 genera were collected : Anopheles sinensis, Tp. b. yaeyamensis, Ae. a. okinawanus, Ae. watasei, Ae. albopictus, Ae. f. miyarai, Ae. riversi, Ar. subalbatus, Cx. halifaxii, Cx. fuscanus, Cx. okinawae, Cx. bicornatus, Cx. ryukyensis, Cx. p. quinquefasciatus and Cx. tritaeniorhynchus. Among them, Ae. albopictus was most dominant, making up 73 to 74% of the total catch in both islands. Ae. aegypti which was recorded frequently before in these islands, was not found in the present survey. 2. The predominant breeding sites of the mosquito were tin cans (31-32% of total sites), small earthen jars (23-24%), plastic containers and tires.

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Tere are many reports of the disease produced by infection with Strongyloides stercoralis. In these reports. various clinical features including symptoms, laboratory findings or certain specific findings in roentgenological examination of the gastrointestinal tract are described.But none of these have mentioned the findings of the endoscopic observation of duodenum and jejunum. Recently we experienced 4 cases of severe infection with Strongyloides stercoralis. Duodenofiberscopic examination by using FGDS (Machida) revealed serious duodenitis and jejunitis in all of the cases. Mucosal edema, whitish discoloration and turbidity of the mucosa with much of dirty mucus were noticed instead of normal velvety mucosal pattern. In some cases, ulceration or erosions with occaional bleeding were present. Especially in one of the cases, operated on the stomach by means of Billroth-II because of the duodenal ulcer, many shallow ulcers with slight stenosis were displayed in the jejunum. Bringing the f iberscope to the mucosa disclosed that tips of the many of the villi became thickened and club-shaped in all of the cases. These findings were very similar to macroscopic findings of the small intestine in the autopsy cases. Endoscopic biopsy of the jejunal mucosa in the gastrectomized case revealed severe infestation with many larvae as well as adult worms. These findings disappeared in a short period after taking a vermif uge, Thiabendazol. The features revealed by duodenof iberscopic examinations in 4 cases of serious strongyloidiasis are very interesting with regards to the diagnostics of small intestine by use of endoscope. We expect that in the near future it will become possible to observe endos-copically and take biopsy specimens under direct vision throughout the entire small intestine.

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1) 八重山諸島のマラリアは3日熱のほか,わが国に稀な熱帯熱マラリアを含む.著者はその歴史的消長過程を手がかりとして,風土病についての地域の諸構成要素の連関を分析し,やや詳しい記述を試みた.
2) この地域では,日光の照射を必要とするnopheles minimusが,熱帯熱マラリアの強力な媒介者として山麓の渓流・湧泉に棲息し,近世の開墾の進展と津波災害にもとつく森林の減少にともなって,日光を忌む比較的弱い媒介者, Anopheles ohamaiと交代した.近世中期以後にマラリアによる廃村化が急速に進行した1因は,かような生態的作用系列によると推測される.
3) 八重山諸島のマラリアのEndemicareaに,あえて住民を立入らせ,Pandemicな流行を出現させた作用は,近世から明治中期までは人頭税,太平洋戦中の軍による疎開命令,その後には人口過剰による移民促進という,地域外から及んだ社会的作用系列に属する. Endemicareaの地域的構造は,薬品によるマラリア原虫駆除の完了によっても,なお厳存していて,将来何かの原因でマラリア原虫が導入されれば, Pandemyが再現される可能性がある.

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The natural environment of Yaeyama Islands of Okinawa Prefecture are classified into two types; one is Iriomote Island, a large main island which is covered by many mountains and paddy fields, and inhabited by Anopheles minimus, a vector of Plasmodium falciparum, and the other is non endemic peripheral small dry islands of coral reef which have no swamps and paddy fields. Inhabitants of the non-endemic islands engaged in inter-islands cultivation. They stayed in the malaria-endemic island for various periods from one day trip to seasonal staying, the cultivation of rice and getting resources from the forest. This study based on the hearing to the inhabitants and participant observation in Iriomote, an endemic island. They had immigrated from one of the non endemic islands, Aragusuku since the year of 1941. The author tried to reorganize the inter-islands cultivation in the past day and to evaluate the efficiency for the subsistence economy and the adaptation to malaria. On the subsistence economy, inhabitants of Aragusuku had cultivated several crop species like millet and sweet potato by the swidden agriculture and mixed cultivation under a rotation system. Added by the inter-islands cultivation, they cultivated rice and got firewoods and woods for materials for houses from Iriomote Island. Activities in the both islands were essential for their subsistence, as their home island had neither paddy fields nor forests. Hunting wild boars and cattle-breeding were also carried out only in Iriomote Island. Quinine and traditional herbaceous medicines used for the treatment of malaria seemed to have limited effects, i.e., reducing symptoms of malaria, such as fever, discomfort and so on. No effective preventive measures against mosquito-biting was carried out in staying while the endemic island. Invasion of malaria was prevented primarily by limiting the person to stay in Iriomote Island only to male adults excepting the vulnerable group, women and children. It is concluded that the selective participation in inter-islands cultivation was most effective adaptive behavior for reconciling the discrepancy between the benefits of subsistence economy and the disadvantages of the epidemic of malaria.

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A mosquito survey was carried out from 1975 to 1977 to clarify the breeding status of Anopheles, especially a well-known malaria vector, Anopheles minimus minimus Theobald, in Ishigakijima and Iriomotejima, the southern Ryukyus. Larval dipping at streams, and adult catches by a lighttrap, and human-, cow- and dry ice-baited net-traps at different localities were the collecting methods employed. In the present survey, An. m. minimus Theobald, An. saperoi Bohart and Ingram (=An. ohamai Ohama), An. sinensis Wied. (including An. lesteri Baisas and Ho) and An. tessellatus Theobald were collected. An. m. minimus were commonly found, i.e., 1,390 larvae and pupae in total, or 1.84 per dip and 49,or 0.41 per dip in streams of foot-hill areas of Ishigakijima and Iriomotejima, respectively. At the urban area in Ishigakijima, no adult of An. m. minimus and only 8 An. sinensis were collected by light-traps made on 76 nights in the year 1976. On the other hand, at the foot of mountains and paddy regions in both Islands, many adults were collected by light-traps on 26 nights. They consisted of 379 An. sinensis, 37 An. m. minimus and 1 An. tessellatus. An. m. minimus was not only highly anthropophilic but also seemed to be zoophilic. It was most commonly collected by human-baited net-traps on 12 nights (101 females or 92% out of the total 110), and also frequently by cow-baited net-traps on 2 nights (116 females or 32% out of the total 363). An. sinensis was highly zoophilic, as shown by the fact that it was common in cow-baited net-traps. It is particularly noticeable that 18 females of An. m. minimus were attracted to human-baited net-traps near human dwellings in Hoshino village on 2 nights in July 1976. The parous rate of these females was comparatively high, being 25% out of 44 dissected. Such recent increase in number of An. m. minimus seems to have been caused mainly by the increase of the population of cows, the main host animal of the mosquito, and also by the reduction in the degree of pollution in the water of breeding streams.

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Influences of epidemic of Falciparum malaria on the population dynamics of communities and families before the introduction of modern medicine for the prevention and treatment of malaria were evaluated in Yaeyama Islands in Okinawa Prefecture. Population growth and structure in a period (1880-1911) in the Meiji era were compared between 4 hamlets each in the highly infected Iriomote Island (M [Main]-Island) and in the non-infected neighboring peripheral islands (P [Peripheral]-Islands). Although malaria was not endemic in P-Islands, the inhabitants of these islands were also exposed to malaria because they temporarily visited M-Island for cultivating rice and collecting forest resources. Changes of population were examined during two successive periods: period I (1880-1903), during which free moving between hamlets was prohibited by the poll tax law; and period 11 (1903-1911), after the abolition of the law. The results are summarized as follows: 1) The prevalence of malaria in all ages of both sexes was prominently higher in M-Island (26.5%) than in P-Islands (3.4%). The difference in prevalence was prominent among children aged 0-9 years: over 70% in M-Island vs. much less in P-Islands. The prevalence among women in the reproductive age was also higher in M-Island than in P-Islands. 2) Both population and number of households in M-Island hamlets slightly decreased (median was -2.7%o/year in population and -1.2%o/year in households) in period I. This decreasing trend was accelerated in period II (-21%o in population and -13 .5%o in households) by emigration. On the other hand, those in P-Islands highly increased throughout both periods (period I, 16%o increase in population and 18%o in households; period II, 11.8%o in population and 4%o in households). The household members in MIsland hamlets was significantly smaller (median was 3.47 in period I and 3.4 in period II) than in P-Islands (4.75 in period I and 5.74 in period II) in both periods. 3) In period I, when migration was restricted, the ratios of number of children aged under 15 years and of older persons over 50 to the adults aged 15-49 were significantly smaller in M-Island than in P-Islands. 4) The vital statistics in period I were estimated by the West type's stable population model. Crude and infant death rates were significantly higher in M-Island than in PIslands. Life expectancy was also significantly shorter in M-Island. No statistically significant difference in crude birth rate was found between M-Island and P-Islands presumably of a larger variation among the hamlets in M-Island than in P-Islands. 5) These results suggest that the population decrease in M-Island in period I was caused by the high death rate in particular among children due to malaria and related complications. In P-Islands, it is inferred that malaria was only prevalent among men of working age, who engaged in inter-insular cultivation. The low death rate among children and high birth rate in P-Islands are attributable to this communal preventive behavior system against malaria. This probably contributed to the high population growth rate. For the malaria control measures of the day, further efforts should be paid to the evaluation of preventive behavior system focused on children and mothers.

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For a long period Japan was a country with a variety of parasites linked to the geo-climatic features of the country and agricultural modes. However national endeavors to promote parasite controls resulted in the successful elimination of those parasites by around 1970. In this short article, I briefly overview the control programs of soil-transmitted parasites, lymphatic filaria, Schistosoma japonicum and malaria, and cite some of the characteristic features and remarkable facts revealed in the course of individual control programs.

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Seven species of Anopheles, An. bengalensis, An. l. japonicus, An. saperoi, An. sinensis, An. lesteri, An. minimus and An. tessellates, are known to occur in the Ryukyu Archipelago. This review covers and explains the distribution and biology of these species. Historical review on synonymizing An. ohamai with An. saperoi, An. saperoi as a new laboratory vector for Plasmodium y. nigeriense, and the study on its biology for maintenance of laboratory colonization are presented. Furthermore, the susceptibility status of An. sinensis, An. saperoi and An. minimus to several insecticides, mosquito control as a component of malaria eradication program, and the distribution of An. minimus just after malaria eradication and its recent status in the Yaeyama Is. are discussed.

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近代八重山の廃村は，そのほとんどがマラリアによる人口減少が原因とされてきた．しかし一方で，マラリア禍の激しかった西表島において500年以上も存続してきた祖納のような集落も存在する．本稿では，近代廃村期（1900年から1938年）を生き延びたマラリア有病地集落共通の特徴を分析し，その集落存続要因を探った．その結果，不明な点の多い伊原間集落を除き，八重山のマラリア有病地存続集落はすべて蔡温施政期以前からの古集落であった．古集落は，良港や湧き水の存在など立地条件がもともと良く，生活基盤がすでに整備されていたため，近世の地元役人による不正な課税に苦しみながらも人口を維持し得たと考えられる．また，近代廃村期における石垣島と西表島の廃村状況およびマラリア罹患率の違いから，マラリア予防対策は西表島の方がより効果があがったことが明らかになった．資料の多く残る西表島の古集落祖納を事例として検討したところ，住民による自発的集落移動や予防事業への全面的協力があった．祖納のような古集落には，人口減少を回避する強い集落内結束があり，こうした人間関係を基にした社会構造が，マラリア禍を緩和し，集落存続のための生存戦略を生む背景となっていたのである．

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レジリエンスの概念には，新自由主義的な専門家本位の理論である，あるいは保守的な機能主義理論である社会-生態システム（SES）理論を母胎にしているという批判がある。元来SES理論は，生態系の均衡を前提とする機能主義への批判として出発し，複数のアトラクタを仮定する変動に関する理論である。ところが，その変動プロセスを一定の運河化された経路に固定化して考える傾向がある。そこで，本稿では，そのような経路の可塑性を主張している生物学のエピジェネティクスの理論，および記憶の曖昧さや主体的な想起に関する社会理論を参考に，SESにおけるレジリエンス概念の再構成を試みる。現在のSES理論に含まれている記憶の概念は，危機に陥った下位システムを再生する際に用いられる上位システムの結合パターンであり，すでに伝達可能なものとして構造化されている。これに対して，まだ構造化されていない曖昧な記憶を下位システムが想起し，上位システムの記憶を書き換える，そのような記憶の可塑性がありえること，そしてそれが柔軟な強さとしてのレジリエンスには，恐らく重要であることを主張する。そのような想起の事例として，八重山地域の津波とマラリアに関する（生）物の記憶について検討する。

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