This article deals with the study results of the research project titled "Developing Technical Approaches for the Master Plan of the Health Sector International Cooperation". The government project was supported by the Japanese Ministry of Health, Labor and Welfare which was to be implemented for the duration of three years from 2002. The purpose of this research project was to determine the orientation of future DS in the health sectors by reviewing the studies experienced so far and by introducing various study methods and analytical methods for developing health policies and health planning techniques.
The substance of this article was presented by the author as the president discourse at the 19th Annual Meeting of Japan Association for International Health.

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.

In 1999, an insecticide-treated net (ITN) distribution project was started in several malaria-endemic villages in Lao P.D.R., namely Vientiane, Bolikhamxay and Khammouanne Provinces. After the completion of the project, it was found that the ITNs were effective for malaria control based on the analysis of the slide positivity rate for malaria parasites between 1999 and 2000 [6]. We conducted malariometric, entomological and KAP surveys in 2005-06 to confirm the status of malaria and to determine the effectiveness of ITNs in three different socioepidemiological areas (near city, rural and remote), represented by the Xebangfay and Boualapha districts, Khammouanne Province.
A marked decrease in the annual malaria incidence and slide positivity rate was noted from 1999 to 2006 in the two districts. The malaria prevalence was significantly reduced in near city areas (5.6%-10.7% in 1999 to 0% in 2005-06) and rural areas (21.4%-50.9% in 1999 to 0%-1% in 2005-06). Twelve positive cases were recorded in remote areas (3.4 - 7.7% in 2006).
The illiteracy rate was significantly higher among the respondents in the remote (83.9%) than among those in the near city (32.7%) and rural (54%) areas. In all areas, more than 50% of the villagers indicated that they were not aware of malaria. Similarly, about 60% of the respondents were found to have incorrect knowledge concerning malaria transmission. In remote, 40.9% of the respondents were aware of the methods to prevent malaria infection and 49.5% used mosquito nets throughout the year, rates significantly lower than the corresponding rates in near city and rural. The density of persons per net in remote (3.1-5.9) was considerably higher than that in near city (1.8-2.1) and rural (1.2-2.7). Malaria vector mosquitoes, such as An. minimus and An. nivipes were collected by human-baited adult collection, and cow-baited and CDC light traps. The results of the analysis suggested that the lower the number of persons per net the more effective the reduction of malaria morbidity in these areas. It is imperative that ITN distribution and health education regarding malaria be strengthened, especially in remote, but also in other areas.

In malaria endemic areas, people naturally acquire an age-related immunity to malaria. Part of this immunity involves anti-malarial specific antibodies. Acquisition of these malaria-specific antibodies depends not only on exposure to malaria parasites but also on the human genetic predisposition. CTLA-4 is a costimulatory molecule that delivers an inhibitory signal to suppress T-cell as well as B-cell responses. We investigated associations between malaria-specific antibody levels and CTLA-4 polymorphisms in 189 subjects living in a hyper-endemic area of Papua New Guinea (PNG), where both P. falciparum and P. vivax are prevalent. We determined P. falciparum⁄ P. vivax specific IgG⁄IgE levels (Pf-IgG, Pv-IgG, Pf-IgE, Pv-IgE) and polymorphisms in the CTLA-4 gene at position -1661 promoter region (A⁄G), the +49 exon 1 non-synonymous mutation (A⁄G), and the +6230 3‘-UTR (A⁄G). All quantified antibody levels were significantly higher in subjects > 5 years (n = 150) than in subjects ≤ 5 years of age (n = 39). In children ≤ 5 years old, significant associations were detected between CTLA-4 +49 (GG⁄AG vs. AA) and Pv-IgG (median 18.7 vs. 13.7 Μg⁄ml, P = 0.017) and Pv-IgE (266.6 vs. 146.5 pg⁄ml, P = 0.046). No significant difference was observed in subjects > 5 years old. These results suggest that the CTLA-4+49 polymorphism influenced Pv-IgG and Pv-IgE levels among children less than five years old in the studied population, which may regulate the age- and species-specific clinical outcomes of malaria infection.