We recovered Giardia cysts from sewage and estimated the prevalence of giardiasis among inhabitants in Hyogo Prefecture, western Japan. Two 200-ml sewage samples were collected once a month from two different sewage plants (A and B) during a one-year period. After pretreating the samples by filtration and centrifugation in the presence of alcohol and diethyl ether, an immunomagnetic separation method was applied to isolate Giardia cysts. The mean number of cysts recovered from plants A and B were 880⁄L and 2,000⁄L, respectively. Circadian rhythms in the number of cysts detected on each of two examination days were observed with a peak at 10:00 a.m., and seasonal variations in cyst numbers were also observed with two peaks in May and December. By using the data obtained from this survey, we estimated that the prevalence of Giardia infection in habitants in the areas serviced by plants A and B were 0.1-1.1 and 0.1-1.3%, respectively.

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The prevalence of Centrocestus armatus metacercariae in fresh water fishes were examined in Hyogo Prefecture, western Japan for a period of one year from April 2003 to March 2004. Three species of cyprinoid fish, namely Zacco temminckii, Zacco platypus, and Pseudogobio esocinus, were found to harbor metacercariae of C. armatus. The infection rate of metacercariae in Zacco temminckii, Zacco platypus, and Pseudogobio esocinus was 99% (371⁄377), 100% (8⁄8), and 100% (2⁄2), respectively. The mean number of metacercariae recovered was 232 for Z. temminckii, 2,123 for Z. platypus, and 20 for P. esocinus. However, we focused on Z. temminckii in this study because it was found to be the most predominant fish species in the Chikusa River and to have high a metacercariae prevalence as well. In Z. temminckii, metacercariae were distributed in the brain (37%), viscera (35%), muscles (29%) and gills (0%). No metacercariae were recovered from the scales and fins. This is the first report of the occurrence of C. armatus metacercariae in the brain region of the second intermediate fish. The prevalence of C. armatus metacercariae was almost constant throughout the year, and no positive correlation was found between the prevalence and seasonal changes. However, a positive relationship was observed between prevalence of metacercariae and fish length, I.e., the intensity of infection increases with the size of the fish host (p < 0.05). People in the survey area sometimes eat fish raw, indicating enlightenment as well as the countermeasures to prevent C. armatus infection is needed.

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The research project titled “Developing Technical Approaches for the Master Plan of the Health Sector International Cooperation ” has been conducted for the duration of three years from 2002 by the support of grants-in-aid for research on international medical cooperation from the Japanese Ministry of Health, Labor and Welfare. Based upon comprehensive and detailed review on the development studies (DS) in the health sectors so far completed, and throughout extensive and detailed examinations on the various DS related issues at the organized workshops with the parties concerned, the following propositions were made for the orientation and possible improvement of future DS in the health sectors; 1) a master plan in the individual DS to be defined in association with the level of strategy with which the study deals, 2) the instruction of surveys and methods to be more crystallized, 3) appropriate survey methods with reproducibility to be employed, 4) qualitative researches to be complimentarily exercised with quantitative researches 5) the ownership of DS to be cultivated by adoption of participatory methods.

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