著者

吉葉 繁雄

出版者

一般社団法人日本衛生学会

雑誌

日本衛生学雑誌 (ISSN:00215082)

巻号頁・発行日

vol.39, no.2, pp.565-572, 1984

被引用文献数

20

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<i>Conus</i>-sting, 55 cases, including 21 fatalities caused by about 20 species of <i>Conus</i> as of Aug. 1982. Among the 21 fatalities, 18 cases were caused by <i>C. geographus</i>. The fatality rate associated with this species has reached 55.3% in Japan and 66.7% in the world. <i>C. geographus</i> is therefore considered to be the most dangerous snail belonging to the genus <i>Conus</i>. This fact is also proven experimentally by comparison of the lethal dose within 1 hour (LD_1h) of the venom of this species (CGV) in various animals. Results show the values of LD_1h of crude CGV are 1.3mg/kg in mice, 4mg/kg in chickens and 0.09mg/kg in goldfishes. These values represent the lowest value of venoms in various species of <i>Conus</i> examined by the author.<br>However, it is impossible to estimate the lethal dose (even not LD_1h) in humans directly by means of experiment. Therefore the lethal dose for humans was estimated by means of 1) examination of the records of <i>Conus</i>-stings in the world and 2) measurement of the quantity of CGV thought to be injected into a victim by the snail.<br>1) From an analysis of the record of <i>Conus</i>-stings collected by Shirai (June 1982) and 3 cases investigated by the author (Sep. 1982) it can be concluded that <i>C. geographus</i> injects in one attack crude CGV in ammount corresponding to LD₇₀ in humans. Consequently, it was fatal in the cases of small men or children stung by large snails and death came within 40 minutes to 5 hours after the sting but larger men stung by smaller snails were saved.<br>2) It has already been proven by the author that <i>C. geographus</i> injects its venom only in the amount charged within a single radular tooth into the victim according to its predatory behavior. As a result of the measurement of the volume of capacity of a single radular tooth from <i>C. geographus</i> in several sizes, the amount of raw crude CGV which would be injected into a human was converted into 0.06 to 0.2mg in dry weight.<br>Thus the lethal dose of CGV in humans was estimated to be 1 to 3&mu;g/kg. However in 2 cases of <i>geographus</i> cone-stings which occured in Okinawa on Jul. 22 and Aug. 17 in 1982, both doses of CGV are presumed to be only 0.2 and 0.5&mu;g/kg respectively according to the estimation in this report. Yet the patients fell into severe paralysis of voluntary movement accompanied by disturbance of speech and dyspnea. They subsequently recovered in a hospital aided by medical treatment.