ニワトリのLeucocytozoon病の予防に関する研究 I. Culicoides arakawaeの1駆虫剤,DA-14-7に対する態度

In resent years, leucocytozoon infection of the chicken was found all over Japan except in Hokkaido. And it was revealed by AKIBA (1960) that Culicoides arakawae is the intermediate host of Leucocytozoon caulleryi. But the effective insecticide for C. arakawae is not yet discovered. In this study we have tested an insecticide named DA-14-7. This insecticide was manufactured recently for trial by a pharmaceutical company. The procedure and the results obtained are as follows. Two hen-houses of nearly the same scale were used for this experiment. In the control hen-house no insecticide was sprayed. In the experimental hen-house, emulsion of DA-14-7(diluted 1/20 with water) was sprayed on the ceiling, the wall, the beam, the pillar, the droppings board and other parts except the feeder and watering installations, at the rate of 300 ml. per m2. Oily solution of DA-14-7 was also sprayed on the hen body at the rate of 7 ml. per hen. These sprayings were repeated 5 times. The first spraying was carried out on September the 14th 1961. The second one on the next day. After the second spraying, the third, the fourth and the fifth spraying were carried out every four days. After spraying, the number of C. arakawae caught by light trap in the experimental hen house did not decrease, but the ratios of engorged female flies markedly declined. The ratios of engorged C, arakawae caught in the control hen house and the experimental hen house before spraying were between 83 % and 97 %. Seven hours after spraying, the ratios of engorged flies caught in the experimental hen house were from 6.3 % to 1.1 %, and 24 hours later 18.8 %, and 72 hours later from 34.4 % to 38.4 %. We cannot be satisfied with the effect of DA-14-7 as a repellent for C, arakawae. But, if the effective period of sprayed DA-14-7 is made longer and sprayed in relatively short intervals, the DA-14-7 is effective for protecting the chicken from suffering with C. arakawae, and consequently, the opportunity of the chicken to contact leucocytozoon infection and the degree of infection may be diminished considerably.