ZOONOTIC ILLNESS - DETERMINING RISKS AND MEASURING EFFECTS - ASSOCIATION BETWEEN CURRENT ANIMAL EXPOSURE AND A HISTORY OF ILLNESS IN A WELLCHARACTERIZED RURAL-POPULATION IN THE UK

Study objectives - To recruit a representative sample of farmworkers, accurately quantify the range and extent of their animal exposures, an d measure the associated risks of illness. Design - Inception cohort. Setting - The study was undertaken among farmworkers living in five lo cal authority areas in the catchment of Hereford and Preston Public He alth Laboratories, England. Participants - A quota sample of 404 peopl e on 255 agricultural holdings took part. The holdings were selected a t random from the Ministry of Agriculture, Fisheries and Food register . Altogether 58% of eligible subjects approached agreed to participate . Measurements and main results - The sample had the same sex distribu tion as the 1991 census for those giving their occupation as agricultu re. The mean age was significantly (p < 0.01) higher (44.6 years v 42. 2 years) than that of those giving their occupation as agriculture, fo restry or fishing in the census, although the modal range (45-59 years ) was the same. At enrolment interviews, subjects individually reporte d contact with up to nine animal species (mode 4) out of 26 reported i n all. Based on the numbers contacted and the frequency and intimacy o f contact, scores on a ranked ordinal scale from 0-5 were constructed for each species and frequencies for each score were plotted. Subjects also reported past operations and serious illness. A history of pneum onia was significantly (p < 0.05) associated with a pigeon loft on the farm (relative risk (RR) 7.3) and attending farrowing pigs (RR 6.6), and one of leptospirosis with a rat problem on the farm (RR 28.1). Cat tle contact was associated with a significantly lower likelihood (prot ective) of glandular fever (RR 0.19) and rheumatic or scarlet fever (R R 0.12). These effects were significantly related to rankings of the e xtent of exposure.