Hanako Iwashita
Current Organizations / Institutes
The organizations/institutes from the scholar's latest article
Hanako Iwashita has a total of 45 co-authors. Here are the top co-authors by number of shared publications:
Asako Tokizawa
Vietnam Research Station, Center for Infectious Disease Research in Asia and Africa, Institute of Tropical Medicine, Nagasaki University, 1-12-4 Sakamoto, Nagasaki-shi, Nagasaki 852-8523, Japan; Research Center for Child Mental Development, Hamamatsu University School of Medicine, 1-20-1 Handayama, Higashi-ku, Hamamatsu city, Shizuoka 431-3192, Japan
3 shared publicationsNa Ly Tran
Vietnam Research Station, Center for Infectious Disease Research in Asia and Africa, Institute of Tropical Medicine, Nagasaki University, 1-12-4 Sakamoto, Nagasaki-shi, Nagasaki 852-8523, Japan; Division of Bio-Medical Science & Technology, Korea University of Science and Technology (UST), Daejeon 34113, Republic of Korea
3 shared publicationsTaichiro Takemura
Vietnam Research Station, Center for Infectious Disease Research in Asia and Africa, Institute of Tropical Medicine, Nagasaki University, 1-12-4 Sakamoto, Nagasaki-shi, Nagasaki 852-8523, Japan
3 shared publicationsTetsu Yamashiro
Department of Bacteriology, Graduate School of Medicine, University of the Ryukyus, 207 Uehara, Nishiharacho, Okinawa 903-0215, Japan
3 shared publicationsTetsuhiro Sugamoto
International Programs, Japan Anti-Tuberculosis Association, 3-1-24 Matsuyama, Kiyose-shi, Tokyo 204-8533, Japan; Graduate School of International Health Development, Nagasaki University, 1-12-4 Sakamoto, Nagasaki-shi, Nagasaki 852-8523, Japan
3 shared publicationsAnh Hong Quynh Pham
Vietnam Research Station, Center for Infectious Disease Research in Asia and Africa, Institute of Tropical Medicine, Nagasaki University, 1-12-4 Sakamoto, Nagasaki-shi, Nagasaki 852-8523, Japan; Department of Biomedical Chemistry, Graduate of Medicine, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8654, Japan
2 shared publications
Latest Publications
- Open Access
- 22 October 2025
- Published by Springer Nature in Malaria Journal
- Vol. 24 (1) , 1-10
Long-lasting insecticidal net ownership and malaria infection by socio-economic status: a cross-sectional household study in an area along Lake Victoria, Kenya
Background: This study focused on the importance of long-lasting insecticide treated nets (LLINs) in malaria control in a study area where socio-economic disparities are widening. The objective was to assess the effectiveness of LLIN ownership when nets were available for no more than two people, controlling for differences in socio-economic status (SES). It was hypothesized that LLIN effectiveness would differ by SES and that LLIN effectiveness should be analysed with adjustment for differences in SES. Methods: A household level survey was conducted in an area in the Lake Victoria region in Suba North Sub-County, Homa Bay County, Western Kenya between June and September 2021. Through the household survey, the number of people living in the home, the number of LLINs, and demographic data were recorded. The ratio of the number of people reporting sleeping in the house to the total number of LLINs in the home was calculated. Through a school-based malaria survey, researchers administered blood-spot, PCR tests for Plasmodium infection. Community workers linked individual malaria tests to homes that were involved in the household survey through names and geographic identifiers. A generalized linear model (GLM) tested the associations between household parasitaemia risk in children and the ratio of people to LLINs, stratifying on asset-based household level SES measures. Results: The association between sufficient LLIN ownership and household malaria infection status was analysed across SES groups. In middle SES households, sufficient LLIN ownership was significantly associated with lower malaria infection status compared with insufficient LLIN ownership (OR 0.32, 95% CI 0.12–0.92). In the low SES group, a similar trend was observed, although it was not statistically significant (OR 0.59, 95% CI 0.15–2.91). When middle and low SES groups were combined, sufficient LLIN ownership remained significantly associated with lower incidence (OR 0.37, 95% CI 0.17–0.87). Conclusions: The results suggest that promoting the use of one LLIN by no more than two people, as recommended by WHO, can reduce the risk of malaria. Efforts to promote LLINs as an effective means of preventing malaria in children might encourage LLIN compliance and maintain community level control targets. If households have been excluded from LLIN distribution, LLINs should be distributed immediately along with information about their effectiveness. The effectiveness of LLINs varies by region, but strategies to sustain LLIN use should be recognized as contributing to benefits for the entire community.
- 22 October 2025
- Published by Springer Nature in Malaria Journal
- Vol. 24 (1) , 1-10
Open AccessLong-lasting insecticidal net ownership and malaria infection by socio-economic status: a cross-sectional household study in an area along Lake Victoria, Kenya
Background: This study focused on the importance of long-lasting insecticide treated nets (LLINs) in malaria control in a study area where socio-economic disparities are widening. The objective was to assess the effectiveness of LLIN ownership when nets were available for no more than two people, controlling for differences in socio-economic status (SES). It was hypothesized that LLIN effectiveness would differ by SES and that LLIN effectiveness should be analysed with adjustment for differences in SES. Methods: A household level survey was conducted in an area in the Lake Victoria region in Suba North Sub-County, Homa Bay County, Western Kenya between June and September 2021. Through the household survey, the number of people living in the home, the number of LLINs, and demographic data were recorded. The ratio of the number of people reporting sleeping in the house to the total number of LLINs in the home was calculated. Through a school-based malaria survey, researchers administered blood-spot, PCR tests for Plasmodium infection. Community workers linked individual malaria tests to homes that were involved in the household survey through names and geographic identifiers. A generalized linear model (GLM) tested the associations between household parasitaemia risk in children and the ratio of people to LLINs, stratifying on asset-based household level SES measures. Results: The association between sufficient LLIN ownership and household malaria infection status was analysed across SES groups. In middle SES households, sufficient LLIN ownership was significantly associated with lower malaria infection status compared with insufficient LLIN ownership (OR 0.32, 95% CI 0.12–0.92). In the low SES group, a similar trend was observed, although it was not statistically significant (OR 0.59, 95% CI 0.15–2.91). When middle and low SES groups were combined, sufficient LLIN ownership remained significantly associated with lower incidence (OR 0.37, 95% CI 0.17–0.87). Conclusions: The results suggest that promoting the use of one LLIN by no more than two people, as recommended by WHO, can reduce the risk of malaria. Efforts to promote LLINs as an effective means of preventing malaria in children might encourage LLIN compliance and maintain community level control targets. If households have been excluded from LLIN distribution, LLINs should be distributed immediately along with information about their effectiveness. The effectiveness of LLINs varies by region, but strategies to sustain LLIN use should be recognized as contributing to benefits for the entire community.
- Open Access
- 19 July 2024
- Published by Public Library of Science (PLoS) in PLOS Global Public Health
- Vol. 4 (7) , e0003509
Exploring ways to support patients with noncommunicable diseases: A pilot study in Nepal during the COVID-19 pandemic
Global healthcare systems have faced unprecedented strain due to the COVID-19 pandemic, with a profound impact on individuals with non-communicable diseases (NCDs), a scenario particularly pronounced in low-income countries like Nepal. This study aimed to understand the experiences of and challenges faced by patients with NCDs in Nepal during the pandemic, focusing on healthcare service availability and identifying factors affecting healthcare use, with the goal of being prepared for future emergencies. This study utilized a telephonic survey of 102 patients with NCDs and 10 qualitative interviews with healthcare providers in the Kavrepalanchok and Nuwakot districts of Nepal. We used mixed methods, with both qualitative and quantitative approaches. Specifically, multiple correspondence analysis, hierarchical cluster analysis, and classification tree analysis were used as exploratory methods. The study revealed that while 69.6% of the participants reported no difficulty in obtaining medication, other questions revealed that 58.8% experienced challenges in accessing routine medical care. Major barriers, such as fear of infection, unavailability of medicine in rural areas, and lack of transportation, were found through the qualitative interviews. Meanwhile, participants identified innovative strategies, such as telemedicine and community-based awareness programs, as potential facilitators for addressing barriers that arise during pandemic situations such as COVID-19. The COVID-19 pandemic exacerbated challenges in accessing healthcare services for patients with NCDs in Nepal. Our findings suggest the need to design and implement telemedicine services for patients with NCDs, as well as community-based programs that aim to improve health literacy, encourage healthy behavior, prevent development of NCDs, and ensure continuity of care during such crises, especially in countries with limited resources.
- 19 July 2024
- Published by Public Library of Science (PLoS) in PLOS Global Public Health
- Vol. 4 (7) , e0003509
Open AccessExploring ways to support patients with noncommunicable diseases: A pilot study in Nepal during the COVID-19 pandemic
Global healthcare systems have faced unprecedented strain due to the COVID-19 pandemic, with a profound impact on individuals with non-communicable diseases (NCDs), a scenario particularly pronounced in low-income countries like Nepal. This study aimed to understand the experiences of and challenges faced by patients with NCDs in Nepal during the pandemic, focusing on healthcare service availability and identifying factors affecting healthcare use, with the goal of being prepared for future emergencies. This study utilized a telephonic survey of 102 patients with NCDs and 10 qualitative interviews with healthcare providers in the Kavrepalanchok and Nuwakot districts of Nepal. We used mixed methods, with both qualitative and quantitative approaches. Specifically, multiple correspondence analysis, hierarchical cluster analysis, and classification tree analysis were used as exploratory methods. The study revealed that while 69.6% of the participants reported no difficulty in obtaining medication, other questions revealed that 58.8% experienced challenges in accessing routine medical care. Major barriers, such as fear of infection, unavailability of medicine in rural areas, and lack of transportation, were found through the qualitative interviews. Meanwhile, participants identified innovative strategies, such as telemedicine and community-based awareness programs, as potential facilitators for addressing barriers that arise during pandemic situations such as COVID-19. The COVID-19 pandemic exacerbated challenges in accessing healthcare services for patients with NCDs in Nepal. Our findings suggest the need to design and implement telemedicine services for patients with NCDs, as well as community-based programs that aim to improve health literacy, encourage healthy behavior, prevent development of NCDs, and ensure continuity of care during such crises, especially in countries with limited resources.
- Open Access
- 21 February 2022
- Published by MDPI AG in International Journal of Environmental Research and Public Health
- Vol. 19 (4) , 2456
Risk Factors Associated with Diarrheal Episodes in an Agricultural Community in Nam Dinh Province, Vietnam: A Prospective Cohort Study
In Vietnam, data on the risk factors for diarrhea at the community level remain sparse. This study aimed to provide an overview of diarrheal diseases in an agricultural community in Vietnam, targeting all age groups. Specifically, we investigated the incidence of diarrheal disease at the community level and described the potential risk factors associated with diarrheal diseases. In this prospective cohort study, a total of 1508 residents were enrolled during the 54-week study period in northern Vietnam. The observed diarrheal incidence per person-year was 0.51 episodes. For children aged <5 years, the incidence per person-year was 0.81 episodes. Unexpectedly, the frequency of diarrhea was significantly higher among participants who used tap water for drinking than among participants who used rainwater. Participants who used a flush toilet had less frequent diarrhea than those who used a pit latrine. The potential risk factors for diarrhea included the source of water used in daily life, drinking water, and type of toilet. However, the direct reason for the association between potential risk factors and diarrhea was not clear. The infection routes of diarrheal pathogens in the environment remain to be investigated at this study site.
- 21 February 2022
- Published by MDPI AG in International Journal of Environmental Research and Public Health
- Vol. 19 (4) , 2456
Open AccessRisk Factors Associated with Diarrheal Episodes in an Agricultural Community in Nam Dinh Province, Vietnam: A Prospective Cohort Study
In Vietnam, data on the risk factors for diarrhea at the community level remain sparse. This study aimed to provide an overview of diarrheal diseases in an agricultural community in Vietnam, targeting all age groups. Specifically, we investigated the incidence of diarrheal disease at the community level and described the potential risk factors associated with diarrheal diseases. In this prospective cohort study, a total of 1508 residents were enrolled during the 54-week study period in northern Vietnam. The observed diarrheal incidence per person-year was 0.51 episodes. For children aged <5 years, the incidence per person-year was 0.81 episodes. Unexpectedly, the frequency of diarrhea was significantly higher among participants who used tap water for drinking than among participants who used rainwater. Participants who used a flush toilet had less frequent diarrhea than those who used a pit latrine. The potential risk factors for diarrhea included the source of water used in daily life, drinking water, and type of toilet. However, the direct reason for the association between potential risk factors and diarrhea was not clear. The infection routes of diarrheal pathogens in the environment remain to be investigated at this study site.
- 1 August 2021
- Published by Elsevier in Parasitology International
- Vol. 83, 102341
Molecular epidemiology of Cryptosporidium spp. in an agricultural area of northern Vietnam: A community survey
- 1 August 2021
- Published by Elsevier in Parasitology International
- Vol. 83, 102341
Molecular epidemiology of Cryptosporidium spp. in an agricultural area of northern Vietnam: A community survey
- Open Access
- 1 February 2021
- Published by Elsevier in Parasite Epidemiology and Control
- Vol. 12, e00193
Molecular epidemiology of Giardia spp. in northern Vietnam: Potential transmission between animals and humans
- 1 February 2021
- Published by Elsevier in Parasite Epidemiology and Control
- Vol. 12, e00193
Open AccessMolecular epidemiology of Giardia spp. in northern Vietnam: Potential transmission between animals and humans
- Open Access
- 4 December 2020
- Published by Springer Nature in Research Square
Molecular Epidemiology of Cryptosporidium spp. in an Agricultural Area of Northern Vietnam: A Community Survey
BackgroundCryptosporidium spp. is a protozoan parasite with worldwide distribution that causes cryptosporidiosis in humans and other animals. In the countryside of northern Vietnam, where free-roaming livestock are widespread, cryptosporidiosis is an important zoonotic disease. However, there have been few studies of cryptosporidiosis in Southeast Asia from the perspective of zoonotic disease epidemiology. The purpose of this study was to investigate the occurrence of Cryptosporidium infection in both humans and animals and to gain an awareness of the potential threat posed by this zoonotic infection in northern Vietnam.Methods We conducted a community survey to collect information about cases of diarrhea in an agricultural area of northern Vietnam. For this study, a total of 2715 samples (2120 human diarrheal samples, 471 non-diarrheal human samples, and 124 animal stool samples) were collected. A direct immunofluorescence assay (DFA) was used to detect Cryptosporidium spp. oocysts in concentrated stool samples by observation under a fluorescent microscope. DNA extraction, PCR amplification of the three genes (COWP, SSU-rRNA, and GP60), and sequencing analysis were performed to identify Cryptosporidium spp.Results Of 2715 samples, 15 samples (10 diarrheal samples, 2 non-diarrheal samples, and 3 animal stool samples) tested positive by PCR for the COWP gene. Three species of Cryptosporidium spp. were detected; C. canis (from six human diarrheal samples, two human non-diarrheal samples, and one dog sample); C. hominis (from four human diarrheal samples); and C. suis (from two pig samples). In terms of C. hominis, the GP60 subtype IeA12G3T3 was detected in all four human diarrheal samples.Conclusions Although the number of positive samples was very small, our epidemiological data showed that the emerging pattern of each of the three species (C. canis, C. hominis, and C. suis) was different at this study site. For example, zoonotic transmission of C. canis, between dogs and humans was suspected. Further studies are needed to assess the risk of oocyst contamination in the wider environment, including water, in this study area.
- 4 December 2020
- Published by Springer Nature in Research Square
Open AccessMolecular Epidemiology of Cryptosporidium spp. in an Agricultural Area of Northern Vietnam: A Community Survey
BackgroundCryptosporidium spp. is a protozoan parasite with worldwide distribution that causes cryptosporidiosis in humans and other animals. In the countryside of northern Vietnam, where free-roaming livestock are widespread, cryptosporidiosis is an important zoonotic disease. However, there have been few studies of cryptosporidiosis in Southeast Asia from the perspective of zoonotic disease epidemiology. The purpose of this study was to investigate the occurrence of Cryptosporidium infection in both humans and animals and to gain an awareness of the potential threat posed by this zoonotic infection in northern Vietnam.Methods We conducted a community survey to collect information about cases of diarrhea in an agricultural area of northern Vietnam. For this study, a total of 2715 samples (2120 human diarrheal samples, 471 non-diarrheal human samples, and 124 animal stool samples) were collected. A direct immunofluorescence assay (DFA) was used to detect Cryptosporidium spp. oocysts in concentrated stool samples by observation under a fluorescent microscope. DNA extraction, PCR amplification of the three genes (COWP, SSU-rRNA, and GP60), and sequencing analysis were performed to identify Cryptosporidium spp.Results Of 2715 samples, 15 samples (10 diarrheal samples, 2 non-diarrheal samples, and 3 animal stool samples) tested positive by PCR for the COWP gene. Three species of Cryptosporidium spp. were detected; C. canis (from six human diarrheal samples, two human non-diarrheal samples, and one dog sample); C. hominis (from four human diarrheal samples); and C. suis (from two pig samples). In terms of C. hominis, the GP60 subtype IeA12G3T3 was detected in all four human diarrheal samples.Conclusions Although the number of positive samples was very small, our epidemiological data showed that the emerging pattern of each of the three species (C. canis, C. hominis, and C. suis) was different at this study site. For example, zoonotic transmission of C. canis, between dogs and humans was suspected. Further studies are needed to assess the risk of oocyst contamination in the wider environment, including water, in this study area.