Establishment of a stochastic model for variation in fecal Schistosoma japonicum egg count and estimation of its parameters
Yu, J.; Yuan, H.; Chen, Q.; Yang, Q.; De Vlas, S.; Gryseels, B.
Zhonghua Yu Fang Yi Xue Za Zhi 33(1): 37-39
1999
ISSN/ISBN: 0253-9624 PMID: 11864454 Document Number: 507086
To establish a stochastic model suitable for interpreting the variation in fecal Schistosoma japonicum egg count, and to estimate its parameters and to describe it. Total variation in fecal egg count with a stochastic model can be divided into two kinds of sources, (1) inter-individual variation, and (2) intra-individual variation. Parameters in the model were estimated with the data collected in actual fecal egg count. Parameters M and r differed and k kept nearly the same in various age groups. The best cut-off point of r and M for age-splitting was at eight and 12 years, respectively. Parameter k was assumed the same in different age groups in the model E, and r differed in the groups of 2 - 7 years and 8 years of age, and M differed in the groups of 2 - 11 years and 12 years of age, with a minimum value of Akaike information criterion (AIC). Age may be an important factor contributing to the estimations of parameters M and r, and the model E was the best one.