To examine the effects of pesticides on farmers working in vinyl-covered greenhouses, subacute toxicity tests were conducted on rabbits exposed in the greenhouse a period of three months to zinc ethylenebis-dithiocarbamate (ZED) and N-trichloromethylthio-tetrahydrophthalimide (NTT), which had been sprayed once or twice a week. As a result, the authors have arrived at the following conclusions: 1) Either ZED or NTT did not inhibit the growth of the rabbits during the period. 2) Any significant changes attributable to the spraying of both pesticides were not detected in blood, urine and biochemical examinations. 3) Pathohistological examination showed the infiltration of polymorphonuclear leukocytes and histocytes in the interalveolar tissue of the lungs of the NTT-exposed rabbits. However, in the case of the ZED-exposed group of rabbits, the infiltration was so slight that there was veritably no difference from the control group. In the brain, heart, liver, kidney, spleen, suprarenal gland, stomach and intestines, there were no abnormalities worth mentioning. 4) In several cases of the NTT-exposed group, inflammation was observed in their eyes and skins, whereas nothing abnormal were observed in the ZED-exposed group. 5) The concentration of ZED in air within the vinyl greenhouse at a time of spraying was 0.35mg/m3 and NTT measured 0.20mg/m3. After a lapse of one hour, either pesticide was undetectable.
To examine the universal validity of results in preceding reports on hepatitis B antigen among inhabitants of Yachiho village, 4015 farmers in Nagano were investigated. Hepatitis B antigen were detected for 24 persons with single radial immunodiffusion method. The incidence of 0.6 per cent with the insensitive method was compatible with 1.3 per cent in the village with immune adherence hemagglutination method. The prefecture was devided into four areas. The areas where hepatitis B antigen was prevalent persons with elevated transaminase value were frequent.