A cohort study of graphite workers in Sri Lanka.

A cohort of workers from a graphite mine in Sri Lanka was studied in 1987, 1990 and 1993. Radiographic lesions were found in 8.5%, 8.9% and 4.1% of the workers in these respective rounds. When workers with radiographic lesions were clinically examined, a total of 18 cases of graphite pneumoconiosis and seven cases of active pulmonary tuberculosis were detected in the three rounds. The prevalence of both these diseases showed a decline in 1993 when compared to 1987. This favourable situation was probably the result of dust control measures introduced in the mine after 1972. Five workers developed graphite pneumoconiosis in the course of the study. They had worked in the mine for an average of 22.6 years. The right lung appeared to be more vulnerable than the left.

Respiratory function in chilli grinders.

The active principle of chilli is capsaicin which when inhaled induces cough and transient increase in airway resistance through selective stimulation of sensory nerves in the airway. The present study was aimed at determining whether workers exposed to chilli dust showed ventilatory changes as in the pharmacological model. Twenty-five men with an average age of 28.5 years employed in five chilli grinding factories in Sri Lanka for an average of 6.6 years (range 3 months to 20 years) were clinically examined. Their ventilatory measurements were recorded before and after a Monday workshift. A control group was similarly examined. Dust levels in the respective chilli grinding factories were monitored. Fifteen men (60 per cent) had initial symptoms including cough on recruitment, but these passed off in 3 weeks to 6 months. There was no statistically significant across-shift change in ventilatory indices in chilli grinders when compared to the controls, nor was there a significant difference in the pre-shift measurements in the two groups. It is concluded that the airway resistance that occurs in the pharmacological model is too fleeting, if present in chilli grinders, to be recorded under ordinary conditions.

Symptoms in spice workers.

Spices are widely used for flavouring food and are mostly grown in the tropics. Twenty-eight workers in a store processing cloves, pepper, nutmeg, mace and cardamom for export were studied. They were exposed to the dust of these products for short periods, in rotation. Seventy-six per cent of the workers experienced symptoms such as smarting of the nostrils and eyes, cough, sneezing and running nose while handling cloves. Similar symptoms occurred less frequently with pepper (44%). These symptoms were all temporary and lasted only during exposure. Nutmeg, mace and cardamom did not induce any untoward effects. These symptoms, which were absent in a control group, were attributable to irritation of the mucus membranes by the active principles of the spices. A comparison with two other spices, namely chilli and cinnamon, suggests a spectrum in which the frequency of symptoms is proportional to the pungency of the spice.

Asthma in silk workers.

Workers who process raw silk are exposed to a fine dust derived from the gum that binds the strands secreted by the silkworm. Fifty-three such workers, all women and non-smokers with an average of 5.8 years of service in the industry, were examined. Eighteen (33.9 per cent) workers had occupational asthma, the highest proportion (48.2 per cent) being in those twisting silk. A lower prevalence (20.0 per cent) was found in workers in the degumming sector, while the least (16.6 per cent) was in weavers. This declining prevalence in the three processing stages appears to be in line with their declining exposure to dust. The occupational asthma was of the intermediate and late types occurring 30 minutes to 6 hours after starting work and subsiding 1 to 8 hours after leaving the factory.

Graphite pneumoconiosis and its declining prevalence in Sri Lanka.

A study of underground miners in a graphite mine in Sri Lanka was conducted in 1987. Twelve (3.4%) of the 340 workers examined had radiographic lesions suggestive of graphite pneumoconiosis. In comparison, a survey carried out in another mine in Sri Lanka in 1972 showed that 63 (18.3%) of the 344 workers examined had similar lesions. Though the two surveys were comparable, they were conducted in two different mines. Therefore, the conclusion that the reduction in the prevalence of graphic pneumoconiosis was due to the introduction of improved dust control measures could only be tentative.

Clinical and radiographic study of activated carbon workers.

Activated carbon is made in Sri Lanka by passing steam through charcoal made from coconut shells. The carbon does not contain free silica. Sixty six men who had worked in a factory making activated carbon for an average of 7.2 years had no more respiratory symptoms than a control group, and none showed radiological evidence of pneumoconiosis. There was no evidence that people exposed to charcoal and pure carbon for up to 11 years are at risk of developing pneumoconiosis.

Acute symptoms in coffee workers.

Processing of green coffee before export, as carried out in Sri Lanka, is a very dusty process. Thirty-eight workers, who were exposed to coffee dust intermittently, were studied. They developed acute symptoms referrable to the eyes, nostrils and respiratory tract. Cough (84.2%), sputum (76.3%), sneezing (73.7%), difficulty in breathing (63.2%) and running nose (55.3%) were the commonest symptoms. Of the workers 10.5% had a wheeze. These symptoms lasted only during the hours that workers were exposed to the dust, and subsided on returning home after the day's work.

Tuberculin response of Sri Lankan children after BCG vaccination at birth.

A total of 740 healthy children aged between 3 months and 11 years who had received BCG vaccination in the first month of life were Mantoux tested in Sri Lanka. Despite 97% having a visible scar following vaccination, 80% showed Tuberculin anergy (0-1 mm). Those without a scar showed no response. There was no correlation between scar size and the Mantoux response. A low mean Mantoux reaction was seen at all ages: 3.5 mm at 3 months, 3.2 mm at 18 months, 1.8 mm at 5-7 years and 1.9 mm at 9-11 years. A significant waning of the Mantoux reaction occurred at 5-7 years but there was no significant change at 9-11 years. Children who had received routine revaccination at 10 years, having received the first at birth, had a significantly higher mean Mantoux reaction (9.6 mm) when tested 3 months after revaccination. In 90 bacteriologically proven tuberculous patients, there was a significantly increased Mantoux reaction compared to all other groups. 1 T.U. PPD RT 23 (with tween 80) was used in all instances for Mantoux testing. The present study shows that routine BCG vaccination at birth, using a reduced dose of 0.05 ml, is unlikely to interfere subsequently with the diagnostic value of the Mantoux test. However, revaccination at 10 years may do so.