Analysis of the Household Distribution of Trachoma in a Gambian Village Using a Monte Carlo Simulation Procedure

Abstract

Bailey R (Department of Microbiology, Southampton University Medical School, South Academic Block, Southampton General Hospital, Tremona Road, Southampton SO9 4XY, UK), Osmond C, Mabey D C W, Whittle H C and Ward M E. Analysis of the household distribution of trachoma in a Gambian village using a Monte Carlo simulation procedure. International Journal of Epidemiology 1989, 18: 944–951. Studies on the household distribution of trachoma have reached conflicting conclusions. This paper describes a cross sectional survey of endemic trachoma in a Gambian village. Cases of active trachoma were mapped, and the compound and household distribution of the disease analysed by a Monte Carlo simulation procedure which takes into account differences in the size and age distribution within individual households. Significant clustering of active trachoma cases both by village compound (p<0.0001) and bedroom (<0.05) were detected supporting the concept that intra-familial transmission of trachoma is important. There was no evidence of spatial clustering of rooms with higher than expected prevalence of trachoma. Clustering of disease in space or time provides important evidence of infectious aetiology and route of transmission. The methods discussed here are generally applicable in the study of other infections diseases.