SATREPS

Science and Technology Research Partnership for Sustainable Development

Project for Malaria and Neglected Parasitic Diseases Control and Elimination using Advanced Research Technique, Communication Tools and Eco-Health Education (2023-2028) supported by AMED and JICA

About SATREPS

Science and Technology Research Partnership for Sustainable Development (SATREPS) is a Japanese government program that promotes international joint research on global issues, including infectious disease control, energy/environment issues, disaster risk reduction, and food security. Malaria is endemic in mainly southern Provinces in Lao PDR, which means that 2.6 million people (35.3% of the population) are at risk of the infection. Morbidity and mortality of malaria have decreased in Lao PDR through the efforts of the Lao government with the support of partners. The Lao government adopted an ambitious goal to eliminate malaria by 2030. However, several obstacles, such as drug-resistant malaria, asymptomatic or low-density malaria infections, and poor access to healthcare services in remote, hard-to-access villages, are reported. Neglected Tropical Diseases (NTDs), mainly parasitic diseases such as schistosomiasis mekongi, foodborne parasitic diseases, and soil-transmitted helminthiasis, have been neglected in Lao PDR (according to the Lao National Policy and Strategies on NTDs Prevention and Control). These diseases have received less attention because they are chronic diseases and endemic only in low- and middle-income countries. However, the impact of such NTDs is devastating both from a public health and economic point of view for the affected people. The project’s objectives are to achieve malaria elimination and control neglected parasitic diseases (NPDs), such as schistosomiasis mekongi and opisthorchiasis in Lao PDR. By implementing this project, the number of malaria and NPD cases is expected to decrease in Lao PDR. The project will contribute to achieving Universal Health Coverage (UHC) and Goal 3 of the Sustainable Development Goals (SDGs).

Programme Objectives

This project aims to accelerate malaria elimination, schistosomiasis (blood fluke) elimination, and opisthorchiasis (liver fluke) control by developing effective testing and infection prevention technologies, improving surveillance systems using communication technologies, and Ecohealth education. The higher goal of the project is to contribute to the achievement of UHC and SDGs Goal 3, “Health and Wellbeing for All” in Lao PDR.

Signing Ceremony of the Collaborative Research Agreement of the SATREPS between IPL and NCGM

Key activities

Activity 1: Accurate diagnosis of malaria, including asymptomatic malaria parasite infection and low-density malaria parasite infection, is conducted in malaria-endemic areas by utilizing new diagnostic technology.

Installation of Malaria LAMP system in the endemic areas

A highly sensitive DNA diagnosis using malaria LAMP technology has been installed at 25 local healthcare facilities (i.e., District Hospitals or Provincial Hospitals) as a point-of-care test and utilized to detect low-density malaria infections. District hospitals implementing the malaria LAMP testing were selected based on malaria endemicity. The malaria LAMP testing enables the diagnosis of all malaria patients (“no one left behind”) who can benefit from appropriate treatment.

Activity 2: The endemic situation of malaria, including its prevalence in remote areas and the spread of drug-resistant malaria, is identified.

Monitoring drug resistance

**Activity 3: Diagnostic techniques are developed and introduced to monitor the prevalence of Schistosoma mekongi and Opisthorchis viverrini.**

Environmental DNA approach: LAMP & PCR using water samples

Environmental DNA (eDNA) detection of Schistosoma mekongi and Opisthorchis viverrini by PCR and LAMP techniques was developed to allow the creation of infection risk maps for infection prevention. A real-time PCR assay for detecting eDNA of the parasites on site (in the field) using a portable real-time PCR machine will also be developed. Sites for the eDNA study were selected in schistosomiasis and opisthorchiasis endemic areas in Khong and Mounlapamok Districts, Champasak Province.

**Activity 4: The effectiveness of innovative flukes (S. mekongi and O. viverrini) inactivation techniques is evaluated.**

Develop a special feed for snail hosts to inhibit the parasite’s growth

For schistosomiasis mekongi and opisthorchiasis prevention, a special feed containing spirulina that reduces the number of S. mekongi cercariae and O. viverrini cercariae in snail hosts is currently being developed in Lao PDR. The efficacy of this food in reducing the number of S. mansoni cercariae had already been demonstrated in laboratory settings at the Tokyo Medical and Dental University (TMDU)

Develop a pulsed-power system to kill liver fluke in fish

To prevent O. viverrini infection, a novel pulsed-power technology that inactivates Opisthorchis viverrini metacercariae in freshwater fish was developed for installation at a fresh market or selected village in Lao PDR. This technology was developed by Kumamoto University, Japan, and has already been used in Japan for the inactivation of a sea fish parasite (Anisakis) since 2021.

Activity 5: Ecohealth education based on research results is introduced in the model villages

Provide Ecohealth education to the risk populations

“Ecohealth education” is based on systems thinking applied to ecosystems. “Ecosystem-thinking” emphasizes understanding the whole ecosystem from multiple perspectives that consider mutually dependent relationships. Most malaria and NPD patients belong to ethnic minorities who live in remote, hard-to-access villages and poor hygiene conditions, which constitute risk factors for several infectious diseases. Therefore, Ecohealth education for residents of endemic areas, including those from ethnic minorities, will be developed and delivered to improve their knowledge and capacity for malaria and NPD prevention, as well as their health-seeking behavior. Four villages were selected for this study in the Khong and Mounlapamok Districts of Champasak Province, where the annual praziquantel mass drug administration (MDA) is implemented. Two villages benefit from the intervention (Ecohealth education), and the other two are control villages. The prevalence of parasitic infections among the villagers (students and parents) is currently being monitored. A Knowledge, Attitudes, and Practices (KAP) study was conducted prior to the intervention to evaluate its effect.

Capacity Building

Capacity development for young Lao researchers is a key component of the SATREPS project. The project offers opportunities for training courses and studies at universities or research institutes in Japan, including Master’s and PhD programs.

Malaria LAMP Training at CMPE
Portable qPCR Training at CMPE
Droplet Digital PCR Training at IPL
Long-Term training in Japan
- Master course student: University of the Ryukyus in Japan (Ecohealth education for Opisthorchiasis)
- Ph.D. course students: Niigata University (Environmental DNA study) and University of the Ryukyus (Ecohealth education for Malaria)
Short-Term training in Japan

Results and discussion

Malaria LAMP study.

Malaria LAMP methods were implemented in 25 hospitals in the target areas from 2024 to 2025 (Fig. 1). Two days of malaria LAMP training were conducted for hospital staff members by IPL and CMPE staff members. Malaria LAMP refresher training was also conducted annually following the implementation of the method. As of December 2025, 559 LAMP tests were performed. 29 cases were positive with P. vivax, and 1 case was positive with P. vivax and P. falciparum (mixed infection). This result suggested that P. falciparum is close to elimination in Lao PDR. The sensitivity and specificity of the rapid diagnostic test (RDT) were 96.6% and 100.0%, respectively, based on the LAMP results. The Ministry of Health in Lao PDR encourages local hospitals to use the malaria LAMP methods as much as possible. The LAMP method is currently listed as a diagnostic method for malaria in the latest version.

Figure 1. Malaria LAMP method installed sites. The red square shows the malaria LAMP method installed sites.

**Environmental DNA (eDNA) approach for detecting DNA of Schistosoma mekongi, Opisthorchis viverrini, and their host snails.**

To understand the dynamics of Schistosoma mekongi and Opisthorchis viverrini in the environment at the community level, the survey team conducted four water sampling surveys in the dry (February and October) and rainy seasons (May and August) in Khong and Mounlapamok Districts, Champasak Province, in 2025 (Fig. 2). However, water samples could not be collected in Mounlapamok District in August, due to the impact of armed conflict at the Thailand-Cambodia border; JICA restricted travel to Mounlapamok District. Water samples were collected from 10 to 16 sites per village, and three 500 mL bottles of water were collected from each site (Table 1). DNA was extracted from the water samples using a commercially available kit, and Real-time PCR was performed to detect the parasite DNA. By real-time PCR, O. viverrini DNA was detected in some villages, whereas no S. mekongi DNA was detected in 2025. Probe-based real-time PCR methods for detecting their snail hosts were developed. An infection risk map is under development. In 2026, water sampling will be conducted in Khone and Nangloy villages, where S. mekongi DNA was detected in the stool samples with PCR in 2024.

Figure 2. Study sites for eDNA detection and Ecohealth education study in the southern part of Champasak Province.

Seven sentinel sites (villages) for schistosomiasis monitoring were initially selected for eDNA surveys. However, four villages were re-selected as study sites to avoid duplication with other projects.

Locations	No. of sampling sites	No. of samples	No. of sampling sites	No. of samples	No. of sampling sites	No. of samples	No. of sampling sites	No. of samples
	February		May		August		October
Khone	10	30	12	36	15	45	15	45
Phonepuey	11	33	12	36	12	36	15	45
Nady	11	33	13	39	0	0	16	48
Nangloy	10	30	10	30	0	0	15	45
Total	42	126	47	141	27	81	61	183

Table 1. Number of sampling sites and number of water samples in four villages for the eDNA study in 2025.

Study on special feed for host snails of Opisthorchis viverrini.

A special feed containing spirulina was fed to Bithynia spp., the host snail of O. viverrini in Lao PDR and Thailand. The Bithynia spp. was collected in several villages in Vientiane Province in 2025. The snails did not eat the spirulina feed, but when xanthan gum was added to the spirulina powder to form a gel, they began to eat it readily (Fig. 3). The snails were observed with a time-lapse camera for 24 hours. Additionally, the snails and freshwater fish were dissected and observed under a microscope, and a LAMP method was used to detect O. viverrini infection. For future study, a spirulina feeding study will be conducted using an O. viverrini-infected snail in a laboratory setting at IPL.

Figure 3. Spirulina feeding study for Bithynia snail. Green gel is a mixture of spirulina powder and xanthan gum.

Population genetic analyses of Neotricula aperta, host snail of Schistosoma mekongi.

Understanding the genetic diversity and population structure of Neotricula aperta, the snail host of S. mekongi, in relation to its geographical distribution is crucial for a comprehensive understanding of disease transmission. In this study, we investigated the genetic diversity and genetic structure of N. aperta in Champasak Province using coxI and 16S ribosomal RNA gene sequences. The genetic divergence of N. aperta indicated a high level of genetic differentiation both among and within populations (Fig. 4). This pattern suggests that N. aperta is possibly undergoing localized adaptation or that barriers to gene flow, such as physical, ecological, or behavioral factors, are promoting the accumulation of genetic differences. Micro-scale genetic structuring within populations may be driven by microhabitats or small-scale ecological gradients, while limited dispersal, localized mating preferences, or other behavioral traits may contribute to differentiation among populations (Bunchom et al., Trop Med Health, 2025, 53:97).

Figure 4. Median-joining network (MJN) based on mitochondrial coxI gene sequences of Neotricula aperta. Haplotypes are represented by circles. Groups are defined by sub-catchments in the Mekong River (Bunchom et al., Trop Med Health, 2025, 53:97).

Stool survey for schistosomiasis and opisthorchiasis among villagers in the endemic areas.

In October 2025, a stool survey for schistosomiasis and opisthorchiasis among villagers in the four villages (Khone, Phonepuey, Nady, and Nangloy) was conducted. This is an endline survey for the Ecohealth education intervention for opisthorchiasis. This intervention commenced in December 2024, immediately following the mass drug administration that took place in November 2024. A total of 368 stool samples were collected and examined by the Kato-Katz method (microscopy) and probe-based real-time PCR. By the Kato-Katz method, 0 positive cases for S. mekongi eggs were detected, while 47 positive cases for O. viverrini eggs were detected. By the PCR, 4 positive cases for S. mekongi DNA were detected, while 93 positive cases for O. viverrini DNA were detected. S. mekongi DNA was detected in Khone village. A comparison of the stool test results from 2024 and 2025 will be conducted. The effect of the Ecohealth education intervention will also be evaluated.

Ecohealth education study.

The Ecohealth education intervention for opisthorchiasis was conducted from December 2024 to October 2025 (Photo 1). Khone and Nady villages were the intervention villages, while Phonepeuy and Nangloy villages were the control villages (no intervention). A plan for the Ecohealth education intervention was developed by local key persons (teachers, village chiefs, village health volunteers, women’s union members, and Buddhist monks) and implemented by them. The team from the Faculty of Education at the National University of Laos (NUOL), the Pakse Teacher Training College, and Japanese researchers collaborated to support the development of the Ecohealth education intervention plan and to provide support for follow-up activities during the intervention period. For the students, the teachers provided the Ecohealth education at schools. For the adults, village chiefs, village health volunteers, women’s union members, and Buddhist monks provided the Ecohealth education at the temple. The endline survey was conducted in October 2025. A questionnaire survey was conducted among students and their parents. However, the response rate for the questionnaire was low at 58%, so a follow-up survey was also performed in January 2026.

Photo 1. The Ecohealth education intervention for opisthorchiasis at the temple (left) and the school (right) in Champasak Province.

For the Ecohealth education intervention for malaria, a baseline survey was conducted in 5 primary schools in Nong District, Savannakhet Province, from September to October 2025 (Photo 2). The malaria Ecohealth team (Lao TPHI, CMPE, IPL, and Japanese Researchers) created 4 malaria educational video materials in the ethnic minority language in the target villages. A total of 200 tablet devices were procured in November 2025, and the IPL IT team installed the video materials on these devices in December 2025. The Ecohealth education intervention for malaria was implemented from January to May 2026 among the target populations (students and their family members).

Photo 2. Baseline survey at school in Nong District, Savannakhet (left), and 200 tablet devices for viewing the educational video materials (right).

Conclusion and Perspectives

In 2025, we conducted several field surveys on malaria, schistosomiasis, and opisthorchiasis in the endemic areas in Lao PDR. The malaria LAMP method was implemented in the 25 hospitals in malaria-endemic areas, and annual malaria LAMP refresher training was also conducted, except in Khammouane Province, where the refresher training will be performed in May 2026. As of December 2025, 559 LAMP tests were performed. Twenty-nine cases were positive with P. vivax, and one case was positive with P. vivax and P. falciparum (mixed infection). The malaria LAMP method is listed in the latest version of the National Guideline for Malaria Treatment in Lao PDR. We are currently examining mechanisms to enable the Lao Ministry of Health to continue operating the malaria LAMP methods after the project concludes in August 2028.

In the eDNA survey for S. mekongi and O. viverrini, two water samplings were conducted during the dry season (February and October) and two samplings during the rainy season (May and August) in the four villages of Champasak Province. The water samples were collected from 10 to 16 sites per village. Probe-based real-time PCR methods for detecting their snail hosts were developed. An infection risk map is under development. In 2026, water sampling will be conducted in Khone and Nangloy villages, where S. mekongi DNA was detected in the stool samples with PCR in 2024. In the snail feed study, the optimal conditions for the Bithynia snails to consume spirulina feed were determined. In 2026, we plan to feed spirulina to the O. viverrini-infected snails to investigate its effect on suppressing cercariae proliferation in the laboratory setting. The genetic divergence of N. aperta indicated a high level of genetic differentiation both among and within populations. This pattern suggests that N. aperta is possibly undergoing localized adaptation or that barriers to gene flow, such as physical, ecological, or behavioral factors, are promoting the accumulation of genetic differences. To determine the prevalence of S. mekongi and O. viverrini infections in the study villages, a total of 368 stool samples were collected from children and their parents and examined using the Kato-Katz microscopy and PCR. By the Kato-Katz method, 0 positive cases for S. mekongi eggs were detected, while 47 positive cases for O. viverrini eggs were detected. By the PCR, 4 positive cases for S. mekongi DNA were detected, while 93 positive cases for O. viverrini DNA were detected. S. mekongi DNA was detected in Khone village. A comparison of the stool test results from 2024 and 2025 will be conducted. This result will be used to develop control and elimination strategies for parasitic diseases.

From December 2024 to October 2025, the Ecohealth education intervention for opisthorchiasis was implemented in the target villages (Khone and Nady), Khong and Mounlapamok Districts, Champasak Province, led by the local key persons, including teachers, village chiefs, village health volunteers, women’s union members, and Buddhist monks. A questionnaire survey was conducted as an endline survey for the intervention in October 2025. However, the questionnaire response rate was low, so a follow-up survey was conducted in January 2026. From September to October 2025, a baseline survey of the Ecohealth education intervention for malaria was conducted in Nong District, Savannakhet Province. Four educational video materials were created and installed on the tablet devices (n=200). The intervention was implemented from January to May 2026.