It is to be noted that in rural districts where they live and work in fresh and clean air the incidence of chronic obstructive pulmonary diseases is as high as in the districts of air-pollution. Besides, there are a variety of respiratory diseases particularly incidental to life-environment and farm work. To be more informed of their actual conditions, the Japanese Association of Rural Medicine organized a special study group and has carried out various studies for four consecutive years with grants from the Ministry of Health and Welfare. The major results obtained are as follows: (1) There were a variety of farm operations which produced or increased respiratory symptoms, including thrashing and scatteringof agricultural chemicals; (2) It became clear that there existed in an advanced age group certain cases of “agricultural pneumoconiosis” which could be regarded as the terminal of the so-called “thrash-bronchitis” (3) Among the cultivators of rush, raw material for Tatami, there existed cases of pneumoconiosis; (4) There were a variety of agents to produce bronchial asthma, such as rice straw, chaff, tea-leaves and chrysanthemum-leaves; (5) In Japan only two cases of farmer's lung were reported prior to this study. One more case was added to the list by this study group. Besides, cases positive to fungous agents were found among farmers in considerably high percentage.
Five hundred and fifty-six persons associated with dairy farming were surveyed by means of a questionnaire for evidence of farmer's lung. Two hundred and eighty-four of them were evaluated with serological study. Any typical symptom of farmer's lung was not found but precipitating antibody to Thermoactinomyces vulgaris was identified in sera from fifty-five (19.4%). The subjects of the antibody positive group have more frequently cough with phlegm than negative group.
Two hundreds and seventy one cases of sera of farmers (48.8±10.8 yr.) in mountain district of Kumamoto prefecture were examined by gel diffusion test for precipitins to M. faeni, T. vulgaris and other 12 antigens of fungus and pigeon proteins. Ten positive sera (3.7%) from 271 sera tested were detected to M. faeni and 13 were to T. vulgaris. The confidence intervals (95%) of the positive ratiowas calculated 1.8%-6.6%and 2.3%-7.4%, respectively. To other 10 antigens 1-22 sera were positive, such as C. corticale (0.1%-2.7%, as confidence intervals), S.granarius (4.9%-11.4%), P. pullulans (0.4%-3.7%), Aspergillus mix (0.6%-4.2%), Pigeon serum & droppings (0.2%-3.1%), C. acremonium (0.8%-4.7%), T. viride (0.0%-2.0%), Candida (1.6%-6.2%) and P.casei (0.2%-3.1%). NO cases were positive toCladsporium and Alternaria. And 61 cases (17.5%-27.5%) were positive to at least one antigen of all 14 tested. There was no significance of the proportions of positive reactions between male and female, or age groups. But higher percentagewas found in farmers longer experience of works with hay, straw and compost. Thepresence of a positive precipitin test has been considered as unsatisfactory criterion for the diagnosis of the farmer's lung. However, the findings of our survey suggest that farmers in West Japan has been exposed relatively high amount and/or various kinds of fungus antigens throughout the farm works with hay, straw and compost.
The concentration of pesticide that was inspired by speed sprayer (SS) operatorsin spraying a low toxic organophosphorus pesticide (800-fold to 1000-fold dilutions of wettable agent) were measured by the impinger-one respirator-per man measuring system. The mean ± standard error was 0.01116 ± 0.00191 mg/m3. The operators were made to perform the spraying task every day, and the organophosphorus pesticide concentration in the serum was gas-chromatographically measured before and after the task on each day. The maximum concentration after daily task was 0.032μg/2ml in an operator, and 0.061μg/2ml in anassistant. The concentration was already trace or undetectable in many of them the following morning. No apparent tendency for the pesticide to be accumulated was observed even in the operators after spraying the pesticide for 2 consecutivedays. The 24-hour urine was collected from each subject to measure the outputof PNMC (p-nitro-m-crezol). The output tended to be greater in the assistants than in the operators. This finding may be attributed to the fact that the assistants are trasiently exposed to high concentrations of the pesticide in powder form.
1) The molluscicidal effect of 10 agricultural chemicals which are commonly usedby farmers in Saitama Prefecture was tested experimentally against A. ollula in the laboratory. The snails were made to contact with chemical solution for 48 hrs. at 23-25°C, then transferred to new containers with fresh water. The death rate was observed after 1 more hr. LC50 value of Saturn emulsion (Benthiocarb 50%), Saturn-S granule (Benthiocarb 7%, Simetryne 1.5%), MO emulsion (CNP 20%), NIP emulsion (NIP 25%), Sumithion emulsion (MEP 50%), Baysid emulsion (MPP 50%), Disiston granule (Ethylthiometon 5%), Bassa emulsion (BPMC 50%), Kitasin-Pemulsion (IBP 4%), and Lime nitrogen granule (CaNCN 21%) were 13.0, 92.5, 24.8, more than 50, 16.5, 13.5, more than 500, more than 50, more than 50 and 360 ppm. respectively, all figures were far larger than the doses in practical use for each chemicals. So it can not be expected that these chemicals would be effective against the snail in the ordinally practice. 2) Themolluscicidal effect of Lime nitrogen granule was also investigated with the snail in the paddy field where this fertilizer had been applied at an ordinally dose that is 2 Kg per are., 5 days prier to the test. The snails were introduced into the paddy and the mortality rate was observed 1, 2 and 3days after the introduction. The mortality rates of the snails at each day were 7.5%, 11.0% and 12.9% respectively. In the untreated field these figures were 7.0%, 14.9% and 4.4%. It was concluded that Lime nitrogen granule was not effective against the snail at the ordinally dose for the use for fertilizer.
A dermatitis of unknown etiology has occurred among the farmers working in paddyfields in some districts of Tokushima Prefecture, such as Anan, Kainan and Komatsujima. The dermatitis occurs from March to May when rice-planting and weeding are on and is characterized by erythemato-papulo-vesicular eruptions accompanied with severe itching. The chief symptoms are observed on the parts exposed to water, especially on forearms and lower legs. The results of the epidemiologicaland clinical observations indicated that the dermatitis was due to the invasion of cercariae of an avian schistosome. The investigation for snail intermediate hosts was carried out in the paddy fields where the dermatitis occurred. Cercariae of apharyngeal furcocercous type were detected from the fresh water snails (Austropeplea ollula) which were collected most abundantly from the paddy fields during the season of occurence of the dermatitis. The cercaria wasidentified as species belonging to the genus Trichobilharzia and was regarded as the same species as so far described in Saitama Prefecture by Suzuki et al (1973). An experimental infection with the cercaria was performed. A few drops of watercontaining cercariae was placed on the fore-arm of. a voluntor. The cercariae invaded into the skin and produced a dermatitis quite similar to that prevailing in the endemic areas. Therefore, it was concluded that theetiological agent was the cercaria of a species of an avian schistosome.