Summary: BioCaster is an ontology-based text mining system for detecting and tracking the distribution of infectious disease outbreaks from linguistic signals on the Web. The system continuously analyzes documents reported from over 1700 RSS feeds, classifies them for topical relevance and plots them onto a Google map using geocoded information. The background knowledge for bridging the gap between Layman's terms and formal-coding systems is contained in the freely available BioCaster ontology which includes information in eight languages focused on the epidemiological role of pathogens as well as geographical locations with their latitudes/longitudes. The system consists of four main stages: topic classification, named entity recognition (NER), disease/location detection and event recognition. Higher order event analysis is used to detect more precisely specified warning signals that can then be notified to registered users via email alerts. Evaluation of the system for topic recognition and entity identification is conducted on a gold standard corpus of annotated news articles.Availability: The BioCaster map and ontology are freely available via a web portal at http://www.biocaster.org.Contact: collier@nii.ac.jp

BackgroundContact patterns and vaccination decisions are fundamental to transmission dynamics of infectious diseases. We report on age-specific contact patterns in Japan and their effect on influenza vaccination behaviour.MethodsJapanese adults (N=3146) were surveyed in Spring 2011 to assess the number of their social contacts within a 24 h period, defined as face-to-face conversations within 2 m, and gain insight into their influenza-related behaviour. We analysed the duration and location of contacts according to age. Additionally, we analysed the probability of vaccination and influenza infection in relation to the number of contacts controlling for individual's characteristics.ResultsThe mean and median reported numbers of daily contacts were 15.3 and 12.0, respectively. School-aged children and young adults reported the greatest number of daily contacts, and individuals had the most contacts with those in the same age group. The age-specific contact patterns were different between men and women, and differed between weekdays and weekends. Children had fewer contacts between the same age groups during weekends than during weekdays, due to reduced contacts at school. The probability of vaccination increased with the number of contacts, controlling for age and household size. Influenza infection among unvaccinated individuals was higher than for those vaccinated, and increased with the number of contacts.ConclusionsContact patterns in Japan are age and gender specific. These contact patterns, as well as their interplay with vaccination decisions and infection risks, can help inform the parameterisation of mathematical models of disease transmission and the design of public health policies, to control disease transmission.

BACKGROUNDIn 1999 the Communicable Disease Prevention Law of Japan was completely revised into the "New" Infectious Disease Control Law, which reiterated the importance of surveillance and information dissemination and re-organized the surveillance system. This paper is an attempt to illustrate the potential impact of the new surveillance system through a description of the existing surveillance system and data before and after the revision.METHODSAfter a historical review of surveillance system in Japan, the current surveillance system is described. Data sets of actual case numbers reported and incidence rate per 1,000,000 population are compared before and after the revision.RESULTSComparison of the data between the 2 periods revealed that most of the diseases have had declining trends after the new law was enacted with several exceptions. However, although no major break in continuity is observed in seriously perceived disease, in milder diseases there are striking gaps between the numbers reported in the mandatory and sentinel reporting framework. Sentinel reporting framework maintained the continuity of data without major gaps.CONCLUSIONSFrom this perspective, the new surveillance system with two different frameworks of mandatory reporting for severe diseases and sentinel reporting for milder diseases seems to be working well. But continuous efforts should be made for evaluation and improvement of surveillance system and risk communication through the research on data analysis and effective communication method.

The early stage of epidemics of some infectious diseases might be detectable using this simple method.

Kriging analysis improved visualization and understanding of trends in seasonal ILI activity in Japan.

BACKGROUND: The estimation of incidence rates of infectious diseases based on the sentinel surveillance data is rather rare. We attempted to estimate these in 2000 in Japan by the surveillance data, and to evaluate their biases.METHODS: We used the incidences of influenza-like illness and 12 pediatric diseases in each of the sentinel medical institutions in Japan based on surveillance data in 2000. The incidence in all medical institutions was estimated under the assumption that the sentinel medical institutions were randomly selected. The possible bias of this estimate was evaluated in comparison with the hypothetical true incidence obtained as the total incidence in all medical institutions estimated by a regression model using the numbers of all disease outpatients per day from the National Survey of Medical Care Institutions of Japan.RESULTS: The estimated annual incidence rate was 75.6 (95% confidence interval: 72.3-78.7) per 1,000 population in influenza-like illness, and ranged from 1.1 (95% confidence interval: 1.0-1.2) to 285.2 (95% confidence interval: 270.2-300.3) per 1,000 population aged 0-19 years among 12 pediatric diseases. The ratio of the estimated incidence to the hypothetical true one was 1.06-1.26 among influenza-like illness and the 12 pediatric diseases.CONCLUSIONS: The incidence rates of influenza-like illness and pediatric diseases in 2000 in Japan were estimated from sentinel surveillance data. The rates obtained provide some useful but not always accurate information. Thus, further research is necessary. J Epidemiol2003;13:136-141.

We describe the epidemiology of a pertussis outbreak in Japan in 2010–2011 and Bordetella holmesii transmission. Six patients were infected; 4 patients were students and a teacher at the same junior high school. Epidemiologic links were found between 5 patients. B. holmesii may have been transmitted from person to person.

It is clarified from the NESID that neurologic complications such as acute encephalitis/encephalopathy, apart from Reye's syndrome, have occurred associated with influenza virus infection, especially among young children. Further investigation should be necessary to find the pathogenesis of this serious complication of influenza virus infection and whether this is unique in Japan, due to unclarified factor/factors, or whether it has not been recognized in other countries.