[Establishment of a stochastic model for variation in fecal Schistosoma japonicum egg count and estimation of its parameters].
OBJECTIVE
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.


METHODS
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.


RESULTS
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).


CONCLUSIONS
Age may be an important factor contributing to the estimations of parameters M and r, and the model E was the best one.
Yu
J
J
Department of Preventive Medicine, School of Medicine, Shanghai Tiedao University, Shanghai 200070.
Yuan
H
H
Chen
Q
Q
Yang
Q
Q
De Vlas
S
S
Gryseels
B
B
D000293:Adolescent; D000818:Animals; D002648:Child; D002675:Child, Preschool; D005243:Feces / Q000469:parasitology*; D006801:Humans; D008433:Mathematics; D015233:Models, Statistical; D010270:Parasite Egg Count; D012549:Schistosoma japonicum / Q000302:isolation & purification*; D013269:Stochastic Processes