A genome‐wide association study (GWAS) is a powerful tool in investigating genetic contribution, which is a crucial factor in the development of complex multifactorial diseases, such as type 2 ...diabetes mellitus. Type 2 diabetes mellitus is a major healthcare burden in the Western Pacific region; however, there is limited availability of genetic‐associated data for type 2 diabetes in Southeast Asia, especially among the Kinh Vietnamese population. This lack of information exacerbates global healthcare disparities. In this study, 997 Kinh Vietnamese individuals (503 with type 2 diabetes and 494 controls) were prospectively recruited and their clinical and paraclinical information was recorded. DNA samples were collected and whole genome genotyping was performed. Standard quality control and genetic imputation using the 1000 Genomes database were executed. A polygenic risk score for type 2 diabetes was generated in different models using East Asian, European, and mix ancestry GWAS summary statistics as training datasets. After quality control and genetic imputation, 107 polymorphisms reached suggestive statistical significance for GWAS (≤5 × 10−6) and rs11079784 was one of the potential markers strongly associated with type 2 diabetes in the studied population. The best polygenic risk score model predicting type 2 diabetes mellitus had AUC = 0.70 (95% confidence interval = 0.62–0.77) based on a mix of ancestral GWAS summary statistics. These data show promising results for genetic association with a polygenic risk score estimation in the Kinh Vietnamese population; the results also highlight the essential role of population diversity in a GWAS of type 2 diabetes mellitus.
Recent advances in G6PD deficiency screening and treatment are rapidly changing the landscape of radical cure of vivax malaria available for National Malaria Programs (NMPs). While NMPs await the ...WHO's global policy guidance on these advances, they will also need to consider different contextual factors related to the vivax burden, health system capacity, and resources available to support changes to their policies and practices. Therefore, we aim to develop an Options Assessment Toolkit (OAT) that enables NMPs to systematically determine optimal radical cure options for their given environments and potentially reduce decision-making delays. This protocol outlines the OAT development process.
Utilizing participatory research methods, the OAT will be developed in four phases where the NMPs and experts will have active roles in designing the research process and the toolkit. In the first phase, an essential list of epidemiological, health system, and political & economic factors will be identified. In the second phase, 2-3 NMPs will be consulted to determine the relative priority and measurability of these factors. These factors and their threshold criteria will be validated with experts using a modified e-Delphi approach. In addition, 4-5 scenarios representing country contexts in the Asia Pacific region will be developed to obtain the expert-recommended radical cure options for each scenario. In the third phase, additional components of OAT, such as policy evaluation criteria, latest information on new radical cure options, and others, will be finalized. The OAT will be pilot-tested with other Asia Pacific NMPs in the final phase.
Human Research Ethics Committee approval has been received from the Northern Territory, Department of Health, and Menzies School of Health Research (HREC Reference Number: 2022-4245). The OAT will be made available for the NMPs, introduced at the APMEN Vivax Working Group annual meeting, and reported in international journals.
A new analytical approach to the nonlinear buckling and postbuckling analyses of functionally graded graphene-reinforced composite laminated cylindrical shells stiffened by functionally graded ...graphene-reinforced composite laminated stiffeners under external pressure taking into account the elastic foundation effect in a uniformly distributed thermal environment is presented in this paper. An improved smeared stiffener technique is developed for anisotropic stiffeners, and a special design for ring and stringer functionally graded graphene-reinforced composite laminated stiffeners is presented and successfully applied in this paper. The governing equations for the cylindrical shells are established by using the Donnell shell theory with the geometrical nonlinearity term in the von Kármán sense with the shell-foundation interaction formulated by the Pasternak elastic foundation model. A three-term solution form is chosen for the deflection, the stress function is introduced, and the Galerkin method is used to establish the nonlinear postbuckling relation. The numerical results validate the effects of the stiffeners, volume fraction of graphene, type of graphene distribution of the shell skin and stiffeners with different geometrical parameters, elastic foundation moduli, and uniformly distributed temperature changes on the nonlinear buckling and postbuckling behaviors of stiffened cylindrical shells.
Despite great success in significantly reducing the malaria burden in Viet Nam over recent years, the ongoing presence of malaria vectors and Plasmodium infection in remote forest areas and among ...marginalised groups presents a challenge to reaching elimination and a threat to re-emergence of transmission. Often transmission persists in a population despite high reported coverage of long-lasting insecticidal nets (LLINs), the mainstay control method for malaria. To investigate what factors may contribute to this, a mixed-methods study was conducted in Son Thai commune, a community in south-central Viet Nam that has ongoing malaria cases despite universal LLIN coverage. A cross-sectional behavioural and net-coverage survey was conducted along with observations of net use and entomological collections in the village, farm huts and forest sites used by members of the community.
Most community members owned a farm hut plot and 71.9% of adults aged 18+ years sometimes slept overnight in the farm hut, while one-third slept overnight in the forest. Ownership and use of nets in the village households was high but in the farm huts and forest was much lower; only 44.4% reported regularly using a bednet in the farm and 12.1% in the forest. No primary anopheline species were captured in the village, but Anopheles dirus (s.l.) (n = 271) and An. maculatus (s.l.) (n = 14) were captured as far as 4.5 km away in farm huts and forest. A high proportion of biting was conducted in the early evening before people were under nets. Entomological inoculation rates (EIR) of An. dirus (s.l.) were 17.8 and 25.3 infectious bites per person per year in the outdoor farm hut sites and forest, respectively, for Plasmodium falciparum and 25.3 in the forest sites for P. vivax.
Despite high net coverage in the village, gaps in coverage and access appear in the farm huts and forest where risk of anopheline biting and parasite transmission is much greater. Since subsistence farming and forest activities are integral to these communities, new personal protection methods need to be explored for use in these areas that can ideally engage with the community, be durable, portable and require minimal behavioural change.
Despite the well-documented clinical efficacy of artemisinin-based combination therapy (ACT) against malaria, the population-level effects of ACT have not been studied thoroughly until recently. An ...ideal case study for these population-level effects can be found in Vietnam's gradual adoption of artemisinin in the 1990s.
Analysis of Vietnam's national annual malaria reports (1991-2014) revealed that a 10% increase in artemisinin procurement corresponded to a 32.8% (95% CI 27.7-37.5%) decline in estimated malaria cases. There was no consistent national or regional effect of vector control on malaria. The association between urbanization and malaria was generally negative and sometimes statistically significant.
The decline of malaria in Vietnam can largely be attributed to the adoption of artemisinin-based case management. Recent analyses from Africa showed that insecticide-treated nets had the greatest effect on lowering malaria prevalence, suggesting that the success of interventions is region-specific. Continuing malaria elimination efforts should focus on both vector control and increased access to ACT.
Vietnam has successfully reduced malaria incidence by more than 90% over the past 10 years, and is now preparing for malaria elimination. However, the remaining malaria burden resides in individuals ...that are hardest to reach, in highly remote areas, where many malaria cases are treated through the informal private sector and are not reported to public health systems. This qualitative study aimed to contextualize and characterize the role of private providers, care-seeking behaviour of individuals at high risk of malaria, as well as risk factors that should be addressed through malaria elimination programmes in Vietnam.
Semi-structured qualitative interviews were conducted with 11 key informants in Hanoi, 30 providers, 9 potential patients, and 11 individuals at risk of malaria in Binh Phuoc and Kon Tum provinces. Audio recorded interviews were transcribed and uploaded to Atlas TI™, themes were identified, from which programmatic implications and recommendations were synthesized.
Qualitative interviews revealed that efforts for malaria elimination in Vietnam should concentrate on reaching highest-risk populations in remote areas as well their care providers, in particular private pharmacies, private clinics, and grocery stores. Among these private providers, diagnosis is currently based on symptoms, leaving unconfirmed cases that are not reported to public health surveillance systems. Among at-risk individuals, knowledge of malaria was limited, and individuals reported not taking full courses of treatment, a practice that threatens selection for drug resistance. Access to insecticide-treated hammock nets, a potentially important preventive measure for settings with outdoor biting Anopheles vectors, was also limited.
Malaria elimination efforts in Vietnam can be accelerated by targeting improved treatment, diagnosis, and reporting practices to private pharmacies, private clinics, and grocery stores. Programmes should also seek to increase awareness and understanding of malaria among at-risk populations, in particular the importance of using preventive measures and adhering to complete courses of anti-malarial medicines.
Abstract
Background
Malaria rapid diagnostic tests (RDTs) remain the main point-of-care tests for diagnosis of symptomatic
Plasmodium falciparum
malaria in endemic areas. However, parasites with gene ...deletions in the most common RDT target, histidine rich protein 2 (
pfhrp2
/HRP2), can produce false-negative RDT results leading to inadequate case management. The objective of this study was to determine the prevalence of
hrp2/3
deletions causing false-negative RDT results in Vietnam (Gia Lai and Dak Lak provinces).
Methods
Individuals presenting with malaria symptoms at health facilities were screened for
P. falciparum
infection using light microscopy and HRP2-RDT (SD Bioline Malaria Antigen Pf/Pv RDT, Abbott). Microscopically confirmed
P. falciparum
infections were analysed for parasite species by 18S rRNA qPCR, and
pfhrp2
and
pfhrp3
exon2 deletions were investigated by nested PCR.
pfhrp2
amplicons were sequenced by the Sanger method and HRP2 plasma levels were determined by enzyme-linked immunosorbent assay (ELISA).
Results
The prevalence of false-negative RDT results among symptomatic cases was 5.6% (15/270). No
pfhrp2
and
pfhrp3
deletions were identified. False-negative RDT results were associated with lower parasite density (p = 0.005) and lower HRP2 plasma concentrations (p < 0.001), as compared to positive RDT.
Conclusions
The absence of
hrp2/3
deletions detected in this survey suggests that HRP2-based malaria RDTs remain effective for the diagnosis of symptomatic
P. falciparum
malaria in Central Vietnam.
In-line with the World Health Organization's (WHO) Global Technical Strategy for Malaria (2016-2030), Vietnam is striving to eliminate malaria by 2030. Targeting appropriate interventions in ...high-risk populations such as forest and forest-fringe communities is a critical component of malaria elimination efforts in Vietnam. In 2016, a household-level malaria indicator survey was conducted in Phu Yen Province, Vietnam with the aim of assessing the knowledge, behaviors and associated risks of malaria infection among priority mobile and migrant populations (MMPs) working and sleeping in forests and on farms. A total of 4211 people were included in the survey, comprised of 1074 heads of households and 3137 associated household members. Of the 1074 head-of-household respondents, 472 slept in a forest, 92 slept on a farm, 132 slept in both forests and farms, and 378 slept at their villages within the last 12 months. Age, literacy, and occupation were significantly different among those who slept in a forest versus on a farm. Of 301 respondents who answered questions about malaria risk factors at sleeping sites, 35% were somewhat aware of malaria prevention practices, but only 4% could recall at least four malaria prevention messages. Among the same group of 301 respondents, only 29% used nets and only 11% used treated nets. Ownership and use of nets among forest-goers was significantly lower than those who slept on a farm or in their village. Huts without walls were significantly prominent forest sleeping site locations (POR = 10.3; 95% CI 4.67-22.7). All respondents who slept in a forest requested standby malaria drugs and one-third of them self-treated without blood testing. Results from this study highlight the importance of capturing relevant location-specific data among priority populations such as remote forest and farm going mobile and migrant populations in Vietnam. Data regarding behavioral practices, knowledge, preventative measures, and intervention coverage at remote-area transmission sites must be routinely captured to effectively monitor progress and refine targeted intervention strategies accordingly.
In Vietnam, a large proportion of all malaria cases and deaths occurs in the central mountainous and forested part of the country. Indeed, forest malaria, despite intensive control activities, is ...still a major problem which raises several questions about its dynamics.A large-scale malaria morbidity survey to measure malaria endemicity and identify important risk factors was carried out in 43 villages situated in a forested area of Ninh Thuan province, south central Vietnam. Four thousand three hundred and six randomly selected individuals, aged 10-60 years, participated in the survey. Rag Lays (86%), traditionally living in the forest and practising "slash and burn" cultivation represented the most common ethnic group. The overall parasite rate was 13.3% (range 0-42.3 while Plasmodium falciparum seroprevalence was 25.5% (range 2.1-75.6). Mapping of these two variables showed a patchy distribution, suggesting that risk factors other than remoteness and forest proximity modulated the human-vector interactions. This was confirmed by the results of the multivariate-adjusted analysis, showing that forest work was a significant risk factor for malaria infection, further increased by staying in the forest overnight (OR= 2.86; 95%CI 1.62; 5.07). Rag Lays had a higher risk of malaria infection, which inversely related to education level and socio-economic status. Women were less at risk than men (OR = 0.71; 95%CI 0.59; 0.86), a possible consequence of different behaviour. This study confirms that malaria endemicity is still relatively high in this area and that the dynamics of transmission is constantly modulated by the behaviour of both humans and vectors. A well-targeted intervention reducing the "vector/forest worker" interaction, based on long-lasting insecticidal material, could be appropriate in this environment.
Long-lasting insecticidal hammocks (LLIHs) are being evaluated as an additional malaria prevention tool in settings where standard control strategies have a limited impact. This is the case among the ...Ra-glai ethnic minority communities of Ninh Thuan, one of the forested and mountainous provinces of Central Vietnam where malaria morbidity persist due to the sylvatic nature of the main malaria vector An. dirus and the dependence of the population on the forest for subsistence--as is the case for many impoverished ethnic minorities in Southeast Asia.
A social science study was carried out ancillary to a community-based cluster randomized trial on the effectiveness of LLIHs to control forest malaria. The social science research strategy consisted of a mixed methods study triangulating qualitative data from focused ethnography and quantitative data collected during a malariometric cross-sectional survey on a random sample of 2,045 study participants.
To meet work requirements during the labor intensive malaria transmission and rainy season, Ra-glai slash and burn farmers combine living in government supported villages along the road with a second home at their fields located in the forest. LLIH use was evaluated in both locations. During daytime, LLIH use at village level was reported by 69.3% of all respondents, and in forest fields this was 73.2%. In the evening, 54.1% used the LLIHs in the villages, while at the fields this was 20.7%. At night, LLIH use was minimal, regardless of the location (village 4.4%; forest 6.4%).
Despite the free distribution of insecticide-treated nets (ITNs) and LLIHs, around half the local population remains largely unprotected when sleeping in their forest plot huts. In order to tackle forest malaria more effectively, control policies should explicitly target forest fields where ethnic minority farmers are more vulnerable to malaria.
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