DOTS for temporary workers in the agricultural sector. An exploratory study in tuberculosis case detection

This study was conducted in the Boland health district of the Cape Winelands of South Africa where there is a high tuberculosis incidence and prevalence. A survey conducted on 211 farms in the study district during 1998, reported that 65% (n = 9042) of all workers on these farms, were temporarily employed. Temporary farm workers live in communities either within or the outskirts of the boundaries of the Boland health district, from where they are transported to work daily.

To estimate the point prevalence of sputum smear-positive tuberculosis among temporary farm workers in the Boland health district, and to determine whether temporary farm workers diagnosed with tuberculosis, have access to anti-tuberculosis treatment.

The study took the form of a cross-sectional active case finding survey amongst adult temporary farm workers (not living on farms) on the four study farms in the Boland health district.

Data was analysed using the Epi Info Version 6 computer programme. Four (4) existing (self-reported) tuberculosis cases were identified and six (6) previously undiagnosed new sputum smear-positive cases of tuberculosis were detected. The total point prevalence was 10 cases of tuberculosis in the cohort of temporary farm workers, resulting in a point prevalence rate of 2,809 cases per 100,000 temporary farm workers (95% CI 1,090-4,527). If the four (4) self-reported cases of tuberculosis are excluded in the calculation, the point prevalence of new sputum smear-positive tuberculosis cases is six (6) and the prevalence rate 1,685 cases per (95% CI 468-2909). Of the four self-reported tuberculosis cases, one indicated that their supply of medication was depleted, whereas the other three indicated that they had the required treatment at home.

Tuberculosis is a major health problem in this region of South Africa and the incidence is projected to increase in correlation with the increasing prevalence of HIV/AIDS. Recent legislative changes in South Africa have resulted in a trend where farmers decrease their permanent work force and increase their use of a temporary work force. The nature of temporary employment in the agricultural industry creates potential difficulties for farm workers to access tuberculosis health care. The early detection and effective case management of this high-risk group presents a special challenge to the South African health community.