Relating serum circulating anodic antigens to faecal egg counts in Schistosoma mansoni infections: a modelling approach.

摘要: Circulating anodic antigen (CAA) levels in serum and faecal egg counts are both quantitative measures of Schistosoma mansoni worm burdens. In this study, we have tested whether circulating antigens can be included into an established count model. A data set with 3 repeated CAA measurements 50 individuals from a community Burundi moderate endemicity was used. By means Monte Carlo simulation, were related to underlying pair distribution, taking account the variation (within individuals) burdens (between individuals). Models various assumptions (e.g. presence or absence density-dependent production) tested. Whereas observed predicted agreed fairly well, could not described satisfactorily. particular, number negative concentrations much lower than observed, while light positives overestimated. There seems mechanism that causes shift expected (low) positive towards zeros, which proposed models do provide for. Possible biological as well assay-related mechanisms may for discussed. The assumption simple direct reflection (pair) corroborated by modelling exercise. Apparently, relationship between (measured) concentrations, human S. infections is more complex assumed.