The activity of a venomous snake, habu (Trimeresurus flavoviridis) was represented by the frequencies of bites of sleeping men in the Okinawa Islands. Five climate factors recorded at the Okinawa Meteorological Observatory were selected to get correlations to the snake activity on each day in each season through logistic regression analyses. Habu was estimated to be active on the days of low means of air pressure in winter, of high means of air temperature in March, or high means of humidity in autumn. In summer with high means of air temperature and humidity few climate factors were correlated to the snake activity. The patterns of seasonal change in mean temperature and mean humidity corresponded with these results. The mean air temperature, the mean humidity and the precipitation were the first, second and third important factors, respectively, in the analyses of all through the year. This is the first intensive study to analyze the daily change in the snake activity in field.

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For a period of 5 years beginning with 1959, the feeding habits in the wild of the “Hime-Habu” (Trimeresnrus okinavensis) on the Amami Islands were studied, with the following results:
1) The animals fed on were vertebrates of 7 families, 9 genera, 12 species. They were divided as follows: Mammals-2 families, 2 genera, 2 species; Birds-1 family, 1 genus, 1 species; Reptiles-1 family, 3 genera, 3 species; Amphibians-3 families, 3 genera, 6 species.
2) Of the animals in 1), 10 species were recorded for the first time.
3) A total of 31 animals were recorded of which 61.3% were amphibians, 19.4% reptiles, 16.1% mammals, and 3.2% birds.
Of the total, the “Ryukyu Aka-Gaeru” (Rana okinavana) and the “Hanasaki-Gaeru” (Rana narina) accounted for 41.2%. These frogs were presumed to be the principal food of the “Hime-Habu”.
4) Judging from the animals eaten, the “Hime-Habu” was presumed to inhabit narrow forested valleys; observations in the field confirmed this.
5) Judging from the feeding habits and the habitat, the “Hime-Habu” and the “Habu” (Trimeresurus f. flavoviridis) were presumed to be completely allopatric.
6) A maximum length of 783mm for the “Hime-Habu” from the Amami Islands was recorded.
7) An instance of the “Hime-Habu” eating a snake longer than itself was recorded.

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Methods were proposed for estimating the age structure of the Habu, Trimeresurus flavoviridis, from partially aged samples collected in various seasons. These methods were then applied to samples from two districts of the Okinawa Islands. The estimated maturing age of females and generation time were close to those of other temperate snake species.

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The “habu” (Trimeresurus flavoviridis) is a venomous snake which has a distribution among certain islands of the Amami and Ryukyu archipelagoes, and the present study was designed to provide an estimate of the population which is in danger of being bitten by “habu” in the Amami Islands. The results were as follows:
(1) Over the period 1967-1976, a total of 2, 673 cases of “habu” bite occurred in Tokunoshima and Amamiohshima (Amamiohshima proper, Yorojima, Kakeromajima, Ukejima and other small islands). The number of those who had at least one bite in the 2, 673 cases was 2, 583, of whom 2, 502 had been attacked once, 73 twice, 7 three times and one four times. Although we have information only on those who have at least one bite, provided that the total number of cases was derived from the total population combined for Amamiohshima and Tokunoshima, the distribution for the frequency of “habu” bite per head containing those who were not bitten conformed approximately to the negative binomial distribution rather than to the Poisson series. Assuming that the frequency per head for those who have at least one bite is a truncated Poisson distribution rather than a complete series, the size of the population at risk can be estimated by trial and error. The value obtained was approximately 31% of the total population combined for Amamiohshima and Tokunoshima.
(2) The age specific incidence rate was lowest for the youngest age group, increased as age advanced to reach adulthood and then declined again among the most elderly. The estimated age specific incidence rate is introduced by the quadratic function defined by the equation: f(t)=bt+ct² where f (t) is the incidence of bites per year at age t, and b and c are the coefficients which can be estimated by the method of least squares. The total number of cases among the total population can be estimated as the sum of the product of the cumulative value of the estimated incidence rate at each age multiplied by the population corresponding to that age. The value obtained for the total population combined for Amamiohshima and Tokunoshima is 10, 859.16.
(3) If it is assumed that the decimal fraction of those who have at least one bite approached a limit 1, the speed at which this increases can be expressed by the differential equation: dy/dt=(bt+ct²)(1-y) where y is the decimal fraction of those who have at least one bite at age t. Under the condition that y is 0 when t is 0, the equation has the solution y=1-1/exp(bt²/2+ct³/3) The total number of those who have at least one bite can be estimated as the sum of the product of the value of y at each age multiplied by the population corresponding to that age. The value obtained was 9, 181. 12, i. e. 7.3% of the total population combined for Amamiohshima and Tokunoshima.
(4) On the basis that the frequency of bite per capita follows the negative binomial distribution, the number of people corresponding to each class of the frequencies of bites was estimated for the total population combined for Amamiohshima and Tokunoshima.

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1959年9月から5年間にわたり,奄美群島産アカマタの自然界における捕食物を調査し,更に実験的観察をも加えてアカマタの食性を考察し,以下の知見を得た。
1) アカマタの自然界における食餌の種類として,6科・8属・10種を報告した。これを綱別にみれば,爬虫類の4科・6属・7種;両棲類の1科・1属・2種;魚類の1科・1属・1種となっている。
2) アカマタの食餌として,新しく6種を記載した。
3) 本調査で得られた捕食例数は19例で,その綱別捕食率は爬虫類が78.9%(15)で最も高く,ついで両棲類の15.8%(3);魚類の5.3%(1)の順となっている。
これらのうちで蛇類が全体の63.2%(12)を占めており,アカマタがこれらの蛇類を中心とした爬虫類を好食していることを指摘した。
4) 捕食例中,毒蛇の属が全体の31.6%を占めていることから,アカマタととの関係を解析し,アカマタがの天敵としての役割を果していることを指摘して,アカマタの保護対策が必要なことを提唱した。
5) アカマタの食物調査から,魚類の1新種が得られたことを報告した。

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Immunization with heated Habu Snake venom was attempted on guinea pigs.
1. Freund's incomplete adjuvant was added to equivalent volumes of supernatants of heated Habu Snake venom (50mg/1.0ml in 0.85% saline), and 1. 0ml of the mixture was subcutaneously injected into the back of guinea pigs. One week after, 0. 1ml of the heated venom (500γ/0.1ml) was injected one time as additional immunization (booster)
2. When, at two to twelve week after the final immunization, the animals were challenged by injecting 500γ or less of the crude venom into the femoral muscles, the grade and extension of the local damage in them were 1/3 to 1/4 as small as those in the nonimmunized animals.
3. When 0. 1ml of the sera obtained from the immunized animals was mixed in vitro with various amounts of the crude and the heated venoms and the mixture were injected intramuscularly into the legs of mice, they depressed the local pathological changes which were visible after injection of 64γ to 34γ of the crude venom or heated venom obtained from 500γ to 250γ of the crude venom.

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沖縄群島および八重山群島の咬症について沖縄本島内の那覇, コザ, 名護の三保健所ならびに八重山保健所に集計された資料につき整理した資料と, 筆者が現地において直接調査し得た咬症患者ならびに咬症の疫学相をまとめ, さらにこれを奄美の資料と比較したところ次のような興味ある結果がえられた.1)咬症患者の発生は年平均明治末期74.0, 大正年代88.0, 昭和年代111.2, 終戦後332.9と次第に増加し, 人口1, 000人に対する比率も増えているが, 致命率は逆に明治中期18.0, 明治末期16.6, 大正年代16.8, 昭和年代7.1, 終戦後1.83と減少している.(表1) 2)地域別には沖縄本島では北部の山岳地帯が多く, 中南部は比較的少ない.群島内では伊江島が最も多く, 次いで久米島が多い.八重山群島では一番患者の発生が多く罹患率の高いのは黒島で, 小浜島, 石垣島がそれに次ぐ.(表2) 3)市町村別に患者発生が多く罹患率の高いのは, 沖縄北部では伊江村, 国頭村, 今帰仁村, 東村, 本部村, 久志村等で中部では比較的に与那城村, 宜野湾村が多く, 沖縄南部では久米島の外三和村, 玉城村, 具志頭等が受傷率は高い.八重山では市町村別にすると大浜町が患者の発生も罹患率も高い.(表2) 4)咬症の月別発生状況は沖縄, 八重山とも冬に少なく夏に多いが7, 8月にはむしろ減少している.3月, 4月, 5月と温暖になるにつれ患者発生が多くなるが八重山では4月, 沖縄では6月に最高を示し, 以後減少して沖縄では10月, 八重山では11月に再び上昇している.奄美ではこのような山が6月と9月に見られるが.三地方についてみると南にいくにつれ盛夏の谷が長く深くなつている.(表3)(図1) 5)咬症の発生は気候と密接な影響があり, 24℃から29℃迄の発生が最も多く, 雨量や湿度とも密接なつながりがあるようである.(図3) 6)時間的には沖縄, 奄美では0時から23時迄いずれの時間にも患者の発生があるが, 特に奄美では午前10時と夕方7時〜8時頃に多く, 八重山では午前10時と夕方7時〜8時頃に患者の発生が多い外に昼3時頃にも多く, 3つの山をなしている.また深夜0時〜4時迄の発生は八重山サキシマの場合は殆んどないが, 奄美, 沖縄のにおいては比較的に高い.(表5) 7)年齢別の発生状況は各年齢層とも男子に多くて女子に少なく, 沖縄では男女比は100 : 66で, 八重山では100 : 44である.年齢別にみると両地方とも10歳未満は少なく, 15歳以上になると急激に患者が増加し, 以後年齢が進むにつれやや漸増しているが20歳〜29歳が最高で老年期には少なくなつている.(表6, 表7) 8)罹患場所についてみると, 沖縄では最も多いのは山野(31.9%)であるが, 道路歩行中(27.7%)屋内(26.0%)も相当に罹患率が高い.これに反し八重山のサキシマの場合は耕地(50.9%)が大部分を占め, 屋内での罹患率は僅かに3.1%である.(表8) 9)咬症部位については, , サキシマ共に手足の咬症が罹患率は高いが, の場合はその外, 躯幹(2.8%), 頭, 顔(4.0%), 大腿(2.8%)等にもおよび, これらの部位における致命率は高い.サキシマの場合は足が半分以上(54.3%)を占め, 手(38.9%)の外は下腿と大腿にわずかにあるだけで躯幹, 頭部, 上腕, 等の比率がより明らかに低い.(表9) 10)抗毒血清の使用は致命率の減少をもたらし, この意味では素晴らしい効果を挙げたと推定されるが, 局所の病変には必らずしも著効を奏しない.もつと血清を改良して治療効果を高める必要があると同時に熱地保存に耐えるものが要求される.

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1) 名瀬保健所の野外飼育場に30匹を放ち, 時刻別の出現状況を定量的に観察した.1964年4月19日から4月24日の6夜にわたつて観察した結果, の活動は日暮から日の出に行なわれ, 午前1時に活動の頂点のある一峯性の活動消長を示した.活動の消長は, 温度, 湿度とも相関関係が認められた.咬傷の時刻消長とは全く平行しておらず, 咬傷発生の要因としては, 人間の活動が重要な因子であることを推定した.2) 野外飼育場で捕獲箱の捕獲率を比較した.捕獲率は箱の形で著しく異なつたが, 誘引のために生きたネズミを入れることは効果のないことを認めた.本研究に際し, 多大の御援助を賜わつた鹿児島県名瀬保健所職員の各位に厚く感謝の意を表する.特に小野継男技師には格別の御協力を得ており, 深く感謝の意を表したい.

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The number of habu (Trimeresurus flavoviridis) captured in the period between 1954 and 1977 was counted based upon the records of the Naze Health Center and of the Habu Center of Naze. The Naze Health Center (prefectural) purchases live habu to milk for venom to make antivenin serum. The Habu Center (private enterprise) buys many dead and live habu to make leather goods and habu whisky and also to stage habu-mangoose fights. The total number of habu gathered by both centers may comprise the greater part of the habu captured on Amami Oshima Island. The number of habu seems to decrease year after year, in general, but it fluctuates periodically. The peaks appear at about 5-year intervals, and alternate peaks higher than the others appear at about 9-year intervals.
On Amami Oshima Island, habu inhabit mainly sugarcane fields. The yields of sugarcane (tons/10 ares/year) in the period between 1954 and 1976 correlate some-what with the changes in the number of habu captured.

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In animal experiment, it is necessary that the factors which exist and might act an important role in the purpose of the experiment, should be studied initially according to the purpose of the experiment.
The authors have made an experiment to investigate whether the lethal dose of the snake venom for mice might be affected by the factors such as body weight, sexes of the mice and the route of the inoculation using five strains of mice derived from distinct sources.
As to the relationship between lethal doses and strains of mice, the response of gpc/Y for the venom was the same as that of dd/Y, and especially the strain gpc/Y was regareded as comgaratively homogeneous, since the responses of the strain were found quite similar in repeated observations.
There was no significant difference statistically between gpc/S and dd/S, and gpc/Y and dd/Y in the results obtained. But the susceptibility of the former group (gpc/S and dd/S) was slightly different from the latter, and also some tendency of fluctuation was noted among the results obtained from that group.
Toxicity for mice in connection with the body weight and sex of mice was as follows: LD50 of the venom for mice did not seem to be influenced by the body weight which was within the limit of 14 gram to 17' gram either in gpc/Y and gpc/S and no appreciable difference was seen between each sex as such size of mouse was employed.
However, the LD50 of the venom was affected remarkably by the route of the inoculation. Almost equal results were obtained either from intravenous or intraperitoneal inoculation, while mice resisted firmly to subcutaneous as well as to intramuscular inoculations. The subcutaneous and intramuscular inoculations are hardly regarded as highly accurate methods as their confidence limits of the LD50 are so wide. On the consideration of the results mentioned above, it may by concluded that the subcutaneous and intramuscular inoculation methods are inadequate to estimate the lethal dose of the snake venom for mice.

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　奄美大島,徳之島,沖縄のそれぞれにおける1977～1984年の8年間に発生した咬傷の疫学像を比較し,以下の結果を得た.　1)8年間の咬傷発生数の推移をみると,徳之島と沖縄では減少傾向がみられたが,奄美大島ではほぼ一定の推移を示した.　2)人口1,000人当りの咬傷率には三地域間で大差があるが,農業人口1,000人当り及び農地面積100haあたりの咬傷率の地域間の差は減少している.　3)咬傷発生数の月別分布には地域差がみられ,咬傷のピークに,奄美大島と徳之島では6月,沖縄では10月にみられた.　4)気温,湿度の上昇と共に咬傷発生数は増加するが,気温の場合,24～26℃ でピークに達し,それ以上では再び減少した.　5)年間を通した場合,毎日の咬傷発生数の頻度分布は負の二項分布に適合したが,月別にみるとポワソン分布に適合する傾向が認められた.　6)一人当りの受傷回数の頻度分布を0項の欠けたポワソン分布とみなして推定した「咬傷危険人口」は,奄美大島,徳之島,沖縄で各々,12,787,15,873,9,877であり,全人口に対してそれぞれ,15%,46%,1%に相当した.

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A method for estimating the age of habu, Trimeresurus flavoviridis, established using individuals in captivity, was applied to individuals captured in the wild. Variations of growth in terms of snout-vent length were analysed within and among several districts of the Okinawa Islands. The growth pattern of habu was similar to that of temperate snake species studied previously.

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There are thirteen species of vipers distributing in Japan. Among them, adder (Mamushi in Japanese : Agkistrodon halys blomhoffii) is most common except Amami Island, Kagoshima Prefecture and Okinawa Prefecture.
Although the injection of anti-Mamushi serum to the Mamushi bite cases is very effective, we used to hesitate the use of the serum because of possible occur of the serum disease. Under the background mentioned above, we have successfully treated nine patients of Mamushi bite in a farm village of Kyoto Prefecture by washing the wounds with 5% tannic acid solution which was first demonstrated by Okonogi et al. in 1970.
This method is very easy and useful, and considered to be most appropriate in a case of the following conditions : (1) patient within 15 minutes after bite, (2) patient who has ever treated by anti-Mamushi serum, (3) patient who has allergic constitution, and (4) species of snake bited is doubtful whether it was Mamushi or not.

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The box jellyfish Chironex yamaguchii is a highly venomous cubomedusa, also known as “habu-kurage” in Japan. It is a significant threat to marine activities in Okinawa in southern Japan. Annually, envenomation of the species causes nearly 100 to 200 injuries in the Okinawa Prefecture. The present study developed a species-specific real-time PCR assay to analyze environmental DNA (eDNA) for rapid detection of jellyfish in water samples. Primers and probe were designed based on the sequences of the mitochondrial cytochrome c oxidase subunit I region using tissue samples of nine specimens obtained from the Okinawa Prefecture. The specificity of the real-time PCR assay was confirmed by amplifying the DNA samples of 10 different box jellyfish species. A practical assay for eDNA detection was successful on water samples obtained from the natural habitat of C. yamaguchii. In addition, the degradation rate of eDNA in the tank experiment was 65% of the initial concentration at 1 h, 22% at 12 h, and 3% at 48 h.

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1)の捕獲数の季節消長を4年間にわたつて調べた結果6月に急激な増加のある一峯性の消長で冬期は著るしく減じていた.咬症の消長とは4年共相関が認められたが, 密ではなかつた(危険率5〜1%).2)の野外飼育場での日周活動は全く夜行性で, 午前1時前後に最大となる一峯性のものであつた.咬症の時刻分布とは密な逆相関が存在し(危険率0.5%以下)咬症はの活動性に因果関係なく, 人の活動性に基づくものと考えられた.

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