1998 Fiscal Year Final Research Report Summary

On the estimation of date of infection in an outbreak of diarrhea due to contaminated foods

Research Project

Project/Area Number	09680319
Research Category	Grant-in-Aid for Scientific Research (C)
Allocation Type	Single-year Grants
Section	一般
Research Field	Statistical science
Research Institution	National Institute of Public Health
Principal Investigator	TANGO Toshiro National Institute of Public Health, Library, Director, 附属図書館, 館長 (70124477)
Project Period (FY)	1997 – 1998
Keywords	Maximum likelihood Estimation / Profile Likelihood / Confidence Interval / Regression analysis / Lognormal distribution / Escherichia coli O-157
Research Abstract	This research examined new methods for estimating the date of infection in an outbreak of diarrhea caused by eating foods contaminated by some sort of foodborne pathogens such as Escherichia coli O-157 : H7. Simple methods for calculating maximum likelihood estimator and confidence interval are proposed assuming (1) a common date of infection and (2) the incubation period has a lognormal distribution. Further, to deal with the case where any probability distributions do not fit well to the observed incubation periods, data-driven regression models were proposed using several parameters abstracted from the past observed distributions of incubation periods which have been accumulated in a specially designed data base. The validity and applicability of the proposed methods were illustrated with many past data, some of them are from recent outbreaks of Escherichia coli O-antigen 157 : H-antigen 7 in Japan.

(4 results)