1) When a heating source was approached in front of Trimeresurus flavoviridis whose eyes were covered for the absence of vision, the snake sensitively responded to the radiation. The first reaction of response was tongue flickering and rotation of head to chase the movement of a radiant body and afterwards the snake stroke it. The threshold of the radiation to evoke the snake's first reaction was measured and both sides of the facial pits were plugged using putty and polyvinyl tape. The sensitivity to the radiation was remarkably reduced in this state and became recovered when the plugs were removed. It was proved that the snake could find and strike the warm-blooded pray in the darkness at night and this sensory organ was the facial pits. 2) The radiant body used in this experiment was mostly a small electric heater of which radiant energy was variable in the range under 0.7 cal/sec. The others partially used were a candle with the energy 11.5 cal/sec, a man's hand and a rat, Rattus rattus weighing 80 g whose radiant energy was estimated as 0.222 and 0.083 cal/sec respectively calculated from their basal metabolisms. 3) In the absence of vision, the end-point of sensible radiation from an electric heater was presented as 0.34-3.37 × 10-4 cal/cm2/sec with an average 1.22 × 10-4 cal/cm2/sec among 9 snakes. In the snakes of the plugged pits, no response was observed in the radiation 11.86-21.7 × 10-4 cal/cm2/sec and the end-point of the sensibility was 22.4-58.5 × 10-4 cal/cm2/sec with an average 36.6 × 10-4 cal/cm2/sec. After the plugs were removed the sensitivity was recovered to 0. 32-2. 04 10-4 cal/cm2/sec with an average 0.71 × 10-4 cal/cm2/sec. In the last state, the threshold was one tenth less when a hand or a rat were applied as a radiant source as presenting 0.11 and 0.09 × 10-4 cal/cm2/sec respectively. The radiation from living things was differed from that of the electric heater in irradiating from a certain spread of areas and in having longer wave length of infrared radiation. 4) In a blindholded snake whose end-point of radiant response was first 0.68 × 10-4 cal/cm2/sec and little difference presented in the sensitivity, when one side of facial pits was plugged. The latter value was 0.45 × 10-4 cal/cm2/sec. The median limit of the sensitive field of a pit organ extended not acrossing the sagittal line, 7.4° lateral to the same side and the external limit was 114.30 from the sagittal line in average of 3 specimens. Orientation of striking was still correctly held when one side of pits was plugged.
1) The present author (1966) reported 43 species of Vertebrata belonging to 38 genera and 27 families as natural food of Trimeresurus f. flavoviridis (Hallowell, 1860). The present paper deals with the comparison of acceptance of preys in experimental feeding. 2) The rates of acceptance of Mus musculus, Rattus rattus, and R. norvegicus were 78.2, 72.4 and 56.6 % respectively mainly captured by adult and subadult snakes. The young took only suckling mice. Captive rate of chicken was 60 %caught by adults and subadults but eggs of hen and Coturnix coturnix were never taken. 3) The rates of Reptilia, Gehyra mutilata, Eumeces marginatus and Japalura polygonata were 77.8, 75.0 and 61.3 % respectively mainly taken by young and subadults. The snakes were accepted 9.5 % by adults and subadults. Amhibia, Triturus pyrrhogaster, Rana limnocharis and Rhacophorus japonicus were taken by mainly young and subadults. 4) Fish, Carassinus auratus and Aplochula latipes, and 12 species in Mollusca, Arthropoda and Annelida were not accepted. 5) Differing from warm-blooded animals, snakes were not promptly killed by the bite of “Habu”. 6) As snakes remarkablly refused intake in the captive state, the rates of acceptance presented above may be fur less than in natural environment. In the state of starvation, an adult was reared for 416 days and a snake for 569 days from hatching. 7) Adults especially prefered rats and chicken and the young took Reptilia and Amphibia in the present experiment in close coincidence with natural feeding habit. The preference of prey was not only caused by the kind of preys but also by the comparative size of prey to the snake as the young could not take large size of prey. 8) Trimeresurus usually prefered living Vertebrata and ingested the prey from its head. The dead prey stroken by the one snake were not used to be ingested by the others. In the snake whose poison had been squeezed and also when the snake took a cold-blooded animal, it ingested preys always holding prey in mouth from the initial bite differing from the usual striking of the living warm-blooded animals.
739 cases of Habu snake bite occurred in Amami and Ryukyu Islands in 1964. 109 severe cases were found in 635 cases which were surveyed by us. 72 patients in the severe cases with hypotension, vomitting or other generalized toxic symptoms recovered by the antivenin and other treatment. Severe necrosis of muscles occurred in 15 cases in which 9 cases were led to ankylosis or deformity. 23 cases showed both severe necrosis and generalized symptoms including shock in which 5 died in 24 hours after the envenomations and 11 cases were led to motor disturbances. Severe necrosis frequently occurred in the cases of envenomation of hands or lower legs. Serum sickness was found in 86 cases in which 79 were delayed type and the remaining cases were immediate type.
1) The pyrogenicity and acute toxicity of three venoms (Agkistrodon halys blomhoffii, Trimeresurus flavoviridis and Trimeresurus okinavensis) were studied; the pyrogenicities for rabbits were corresponding to the toxicities for mice. 2) The pyrogenicities of vonoms for rabbits were not so stronger than the pyrogen of E. coli, and they showed monophasic body temperature curves. 3) Venoms potentiated the activity of the pyrogen of E. coli and influenza virus. 4) These results were discussed with some additional experiments.
Three hundred serum specimens were drawn from residents in the Lampung State, a southern part of Sumatera Island, Indonesia, during the period from August to September in 1965. Hemagglutination inhibition antibodies against dengue type 1 (Dl), Japanese encephalitis (JE), and yellow fever (YF) viruses were measured by the microtiter technique (Takatsy-Sever). According to the data collected up to the present time, the following general and immunological conclusions have been obtained : (1) D1 is fairly widely distributed. (2) JE is thought to be endemic, though in minority. (3) The antibodies against YF are detected. Because of the comparatively low titers, however, it is presumed that the positive YF reactions are probably due to crossing with other members of the arboviruses, especially dengue viruses. Extended investigations along with the same line are being scheduled.
An investigation was made on the effects of selective treatments of microfilaria positive cases on the prevalence of microfilaria carriers, and clinical filariasis cases in four districts in southern Amami Islands, Setouchicho, Ukenson, Wadomaricho and Chinacho. 1) In three villages where anual blood surveys and drug treatments have been repeatedly applied since 1958, remarkable reductions in microfilaria positive rate were achieved, and the numbers of cases who turned out negative after the drug was administered were significantly higher than expected from merely by chance. However, the effects have never been complete, due partly to appearance of new positive cases who did not receive previous blood examinations, and to recidive cases who turned out positive again after the treatments were suspended. 2) In the group which received the current standard course of the drug treatment of 72 mg per kg in total, 11.3 % of those who once became negative were found to show microfilariae at later examinations, showing that the treatments were effective, at least in part of the cases, to suppress only temporarily. 3) The effectiveness of the treatment was found to be correlated with the amount of total doses administered per case, and analytical study was made on the relation between the dose and the positive rate and the microfilarial density before and after the drug administration. 4) The attack rates of various filarial manifestations among microfilaria positive cases in three years periods before and after start of the drug treatment were compared with materials accumulated in three districts. It was demonstrated that significant reductions occurred in attacks of fever and lymphadeno-angitis, but no significant changes were seen in those of chyluria, lymphoedema and elephantiasis.
In a previous report of the series a successful result of control against Culex pipiens pallens by an eradication of larvae in the breeding places was presented. It was clearly demonstrated that the age-composition of adult population showed a remarkable trend of getting older as the size of population was reduced. In the present experiment it was intended to investigate the effect of control against adults on the age of adult population. When the control of a population of adult mosquitos could be successfuly achieved one may expect to observe a younger population on reappearance of mosquitos. Three villages in Setouchi-cho, Amami Oshima were selected. These are involved in an area of bancroftian filariasis. The vector is known to be Culex pipiens fatigans. Each house was visited from 20 to 22 hrs at night nearly once a week during the period from June to September 1964. Mosquitos resting indoor were collected by an aspirator. The degree of abundance of mosquitos was expressed by the number collected per house per collector and per 30 minutes of collection. Seventeen species of six genera were collected and among them Culex pipiens fatigans, Culex tritaeniorhynchus, Culex vishnui and Anopheles sinensis were indicated to be main species. Age determination was carried out according to the observation of relics in the ovariolar pedicle as well as of changes in the ovarian tracheoles. Residual spraying of organophosphoric insecticides, namely, Baytex was applied to Katetsu village and Sumithion was adopted for Isu- and Konasa village. 0.5 % emulsion of concentrate of each chemical was sprayed once during the observation period on the walls inside of houses at a dose of 50 ml per square meter. All houses including animal sheds were treated at the same time in respective villages. C. fatigans disappeared in houses in each village immediately after the spraying. The effect remained for more than three weeks then a few number were occasionally collected. However the original level of indoor density had never been regained during two months observation after the treatment. Regarding other main species there were no evidence observed to indicate a significant reduction in the size of indoor population which is due to the spraying. Neither the difference of parous rate or age structure of the four main species of mosquitos were observed between before and after the residual spraying. It seems to be of particular interest that C. fatigans was remarkably suppressed in number by the spraying but the age composition was apparently not affected on reappearence inside of houses. A possible interpretation may be that the residual spraying of insecticides could not affect on the whole adult population of this species but merely repelled its invasion into houses although the possibility of specific and lasting repellency to fatigans should be checked. Based on the present observation the residual spraying of Baytex or Sumithion seems useful to some extent for filariasis control. should the majority of infections be acquired indoor.