Pulmonary Disease Amongst Sisal Workers

Abstract

The sisal industry is economically one of the most important in Kenya as it employs about 8,000 Africans who are engaged on work in 69 sisal plantations in the Colony. This corresponds to about 2 % of the total number of Africans employed in all public services, agricultural, and other indus tries. Employees on sisal estates are broadly speaking subject to the same diseases as other agricultural workers except that possibly tropical ulc?ration of the leg is more prevalent amongst them. The dusty conditions created by the brushing machines in the sisal factories, may, however, cause special hazards, as, apart from the general nuisance value of the dust, and its irritative action on the eyes and the upper respiratory tract, there remains the possibility that it might be responsible for damage to the lung tissue. The only reference in the literature which can be found which deals with the effect of sisal dust on the pulmonary tissues is that of an investigation carried out recently by Martins (1956) who clinically examined 118 operatives employed in the brushing rooms of three sisal estate factories in Mozambique. He reported that respiratory incapacity was more prevalent amongst brushing-room workers than others, and that he could find no flagrant signs of pneumoconiosis ; but it should be pointed out that he had no radiological facilities. Although this report by Martins is the only one available on sisal dust it is well known that other organic dusts of vegetable origin are capable of causing lung damage. Broadly speaking these dusts may affect the lungs in three different ways. First, they may produce allergic, asthmatic, and bronchitic conditions. A classical example is byssinosis, first described by Leach in 1863, and contracted by a considerable proportion of operatives working in the cardor blow-rooms in cotton mills. Asthmatic or bronchitic attacks may also occur amongst workers in the woollen industry (Moll, 1933), and amongst bakers (Anton, 1934; Ordman, 1947) and millers (Linko, 1947). Secondly, pulmonary disease may be caused by the inhalation of organic dust containing bacteria, fungi and moulds, and in particular, pulmonary mycosis may occur amongst persons exposed to moulded grain or hay (Fawcitt, 1936; T?rnell, 1946; Hoffmann, 1946). A variety of fungi may be the causative agents, but M. albicans, M. candida, and A. fumigatus appear to be the most frequent. Other fungi may also cause an allergic state giving rise to asthma and vasomotor rhinitis, and mites con taminating grain have been reported to give rise to pulmonary symptoms (Marcandier and Le Chuiton, 1928; Najera ?ngulo and Dantin Gallego, 1939). Caminita, Baum, Neal, and Schneiter (1947) have incriminated Aerobacter cloacae as being responsible for mill fever in cotton operatives. Schilling (1956) has described the same condition in workers preparing hemp and flax for spinning. A third possibility of pulmonary damage arising from exposure to vegetable dusts may be due, not to the effect of the dust itself, but to a high content of free silica mixed with it. Thus the pulmonary fibrosis in workers occupied in the stemming and redrying of tobacco from North Carolina is not due to the tobacco dust itself but to its admixture with free silica which occurs in high content in the soil in which the tobacco is grown (McCormick, Smith, and Marsh, 1948). Finally there is a group of pulmonary affections caused by organic dusts the aetiology of which are in doubt. One such disease is bagassosis which was first described by Jamison and Hopkins in 1941, and which results from exposure to the dust of the fibre trash remaining after the extraction of sugar from the sugar cane. Dunner, Hermon, and Bagnall (1946) have reported radiological findings of reticulation, mottling, and fibrosis amongst dockers handling grain and seeds, and they concluded that mycotic organisms were unlikely to have caused these changes.