In this study, Salmonella is used as the standard bacterium for evaluation of pollution of water environments. The author continued to improve Salmonella detection by visualization of hydrogen sulfide production, which is characteristic of Salmonella. At the same time, the positivity rate of Salmonella in rural Lao was investigated. According to the survey conducted so far, it has been found that the Salmonella positivity rate in residents of Laos is markedly higher than that in Japan. It is conceivable that the level by contamination of Salmonella in sewage drained from each house in Laos will be higher than that in Japan. There is no sewage treatment facility in Laos even in the capital Vientiane. In the city, a vast wetland named That Luang Marsh functions as sewage reception. In the case of contamination that exceeds the purification capacity of the wetland, detection of Salmonella in the water of the Mekong River will indicate the deterioration of water quality.

Opisthorchiasis is the commonest liver disease caused by Opisthorchis viverrini in Thailand, Lao People’s Democratic Republic (PDR) and Cambodia, which will be a major cause of future human cholangiocarcinoma in these regions. In this short review, we describe the epidemic aspects of this parasite infection and the outline of results of our recent surveys of the fluke in humans and its intermediate hosts in Vientiane Capital, where information on the opisthorchiasis epidemic is insufficient. We examined the stool from a total of 296 persons living in the Phailom village (population, 1545, 1999) from 2011 to 2012. As a result, the intestinal parasitism rate was very high from 54 to 59%. Among intestinal infections, O. viverrini infection was observed at highest rates from 51 to 53%. On the other hand, the rate of infection by nematodes was very low. We also conducted intermediate-host investigations in the river and damp areas at 3 villages in the Vientiane capital and 2 villages in Vientiane Province in 2012. As shown by these results, no Opisthorchis species was detected in 147 samples of the host genus Bythinia. However, metacercariae were detected in 3 samples of Cyclocheilichthys sp. and in a Hampala sp. in 303 cyprinid fishes collected from the Haikham village area of Vientiane Capital.

Bangladesh is considered as a high-risk country for emerging infectious diseases because of its high population density, poverty, and unhygienic conditions. Although control efforts have primarily been focused on major infectious diseases such as diarrheal diseases, tuberculosis, malaria, and HIV infection, the prevalence and impact of many local or minor infectious diseases are still unclarified in this country. In this review, we present our recent experience and outcomes of collaborative research on puerperal infection (PI), which is a poorly defined infectious disease in Bangladesh. PI is the most common complication during the perinatal period in developing countries. We investigated the incidence of individual species of aerobic bacteria causing PIs and their drug resistance, and the genetic traits of isolates during the two-year period (2010–2012). The common species of isolates from patients with PIs were Escherichia coli, Enterococcus faecalis, Staphylococcus haemolyticus, Proteus mirabilis, Staphylococcus aureus, and Klebsiella pneumoniae. A remarkable finding was the high rates of resistance to cephalosporins among Gram-negative bacteria harboring extended-spectrum beta-lactamase genes, which were associated with carbapenem resistance in a few isolates. This study defined the importance of control of antimicrobial resistance in Bangladesh, and provided suggestions for the future direction of collaborative research on infectious diseases in Bangladesh.

In this report, we present a short review of applications of time series analysis, which consists of spectral analysis based on the maximum entropy method in the frequency domain and the least squares method in the time domain, to the incidence data of infectious diseases. This report consists of three parts. First, we present our results obtained by collaborative research on infectious disease epidemics with Chinese, Indian, Filipino and North European research organizations. Second, we present the results obtained with the Japanese infectious disease surveillance data and the time series numerically generated from a mathematical model, called the susceptible/exposed/infectious/recovered (SEIR) model. Third, we present an application of the time series analysis to pathologic tissues to examine the usefulness of time series analysis for investigating the spatial pattern of pathologic tissue. It is anticipated that time series analysis will become a useful tool for investigating not only infectious disease surveillance data but also immunological and genetic tests.

The distribution of vector-borne diseases is changing on a global scale owing to issues involving natural environments, socioeconomic conditions and border disputes among others. Geographic information systems (GIS) provide an important method of establishing a prompt and precise understanding of local data on disease outbreaks, from which disease eradication programs can be established. Having first defined GIS as a combination of GPS, RS and GIS, we showed the processes through which these technologies were being introduced into our research. GIS-derived geographical information attributes were interpreted in terms of point, area, line, spatial epidemiology, risk and development for generating the vector dynamic models associated with the spread of the disease. The need for interdisciplinary scientific and administrative collaboration in the use of GIS to control infectious diseases is highly warranted.

Purpose: The purpose of this study was to identify participant characteristics in the Kumamoto University Regional Center of the Japan Environment and Children’s Study (K-JECS) and to investigate the association of pregnancy outcomes with pregestational maternal body mass index (BMI) and maternal weight gain during pregnancy (MWG).

Methods: The subjects were women with singleton birth, who had been recruited by the K-JECS, and were registered in the data systems for the first and second questionnaires and transcripts of medical records. The subjects were categorized by BMI with further classification by MWG. The chi-squared test and one-way analysis of variance were performed to determine the correlations of BMI and MWG with perinatal outcomes. Logistic regression analysis was performed to examine perinatal outcome risks.

Results: The subject characteristics were similar to the trends observed in the Japanese general population. The odds ratio for natural delivery was low in the overweight groups (OW) and normal weight groups (NW) with excessive weight gain. On the other hand, the risk of cesarean section was high in the OW, and risk of induced or accelerated delivery was high in the NW with excessive weight gain. The risks of preterm birth and LBW were high in the insufficient weight gain groups regardless of BMI. The risks of pregnancy-induced hypertension and gestational diabetes were high in the OW.