High economic growth since the late 1950's has brought about a severe labour shortage in Japan. Japanese industry sought migrant workers as one reliable source of labour. As seasonal and unskilled workers, they were employed in a wide variety of trades ; for example, construction, manufacturing, forestry and transportation. However, some of the migrant work was becoming a principal and nonseasonal occupation, and specialized. Migrant forestry and tunnel-construction work are two examples of such specialized work.
To identify health problems among them, we examined the factors affecting workers' entry into migrant forestry and tunnel-construction work, working conditions, and health care services at the workplace by interviewing 65 migrant wokers identified at Hayama Village in Kochi Prefecture, one of the areas well known for providing migrant wokers. Moreover, we carried out health examinations for vibration disease and pneumoconiosis. In this report, we show the results of analysis on 35 migrant forestry workers.
The main factors affecting their entry into migrant forestry work were unstable and poor socioeconomic conditions in the area and the strong demand for a workforce during the rapid economic growth from the late 1950's in Japan. Most of the wage configuration was for piece and contracted work, which promoted long working hours and above-average consecutive work days. They engaged in cutting down, collecting and transporting trees, using vibrating tools such as chain saws, bush cutters, collecting machines and so on. High levels of vibration-exposure quite exceeded the limit of the Ministry of Labour and lasted continuously over 17 years. A difference in labor conditions and working situations was observed between migrant workers who devoted themselves to migrant forestry work and those who did not. Health care administration including health examinations was inadequate. There had been no case of vibration disease identified at the workplace. However, 68 percent among 25 examinees were diagnosed as suffering from vibration disease. Moreover, 40 percent of the subjects experienced absences of more than 4 days due to occupational accidents.

About 7, 000 workers migrated from Kochi Prefecture in 1965. Recently the number of patients with pneumoconiosis and vibration syndrome has increased among these persons who worked on constructing tunnels. To investigate the health status of these workers, we interviewed 73 of these workers with regard to history of migration, work situations, health condition and so on in Niyodo Village in Kochi Prefecture. Thirty workers were examined for pneumoconiosis and vibration syndrome. Geographical distribution of the areas from which these workers had migrated were also analysed by using the statistical data of Kochi Prefecture in 1965.
The results were as follows:
1) Numerous migrant workers come from the mountain villages along the Shikoku Mountains. In the middle-northern areas, included Niyodo Village, the number of migrant workers was large.
2) Their working conditions in the tunnel were poor and measures for prevention of pneumoconiosis, such as wearing of a dust respirator and drilling the rock with water, were poorly carried out. Vibrating tools were also used for long periods of time.
3) Of 73 workers, 40 have been given the compensation follwing a diagnosis of pneumoconiosis or vibration syndrome.
4) In 23 examinees, silicosis was detected in the chest X-ray examination. Classifications included 13 of type 1, 7 of type 2, and 3 of type 4. Also examinees had subjective symptoms and/or objective findings of vibration syndrome. Eighty seven percent were classified as Grade III according to the criteria of Andreeva-Galanina. Thus, most of migrant workers involved in tunnel construction work had complications of pneumoconsosis and vibration syndrome.

To investigate the effectiveness of Maobushisaishin-to (traditional Japanese herbal medicine; Tsumura TJ-127) in treating the common cold, a clinical comparison between Maobushisaishin-to and a general common cold drug was conducted using the sealed envelope method. The study involved 83 patients in the TJ-127 group and 88 patients in the general cold drug group. No differences in age, gender or the period from the onset of the disease to the beginning of treatment were observed between the two groups.
The results indicated greater than moderate improvement in 81.9% of the TJ-127 group, compared with 60.3% of the compound cold drug group (p<0.01). Further analysis of symptom diaries kept by the patients indicated that TJ-127 provided more rapid relief for symptoms such as fever, feeling feverish, coughing and phlegm than did the general cold drug. No side effects were observed for the TJ-127. These results suggest that TJ-127 is effective in the treatment of the common cold.