Asymptomatic infection is an important obstacle for controlling disease in countries where malaria is endemic. Because asymptomatic carriers do not seek treatment for their infections, they can have high levels of gametocytes and constitute a reservoir available for new infection. We employed a sample pooling/PCR-based molecular detection strategy for screening malaria infection in residents from areas of Myanmar where malaria is endemic. Blood samples (n ‫؍‬ 1,552) were collected from residents in three areas of malaria endemicity (Kayin State, Bago, and Tanintharyi regions) of Myanmar. Two nested PCR and real-time PCR assays showed that asymptomatic infection was detected in about 1.0% to 9.4% of residents from the surveyed areas. The sensitivities of the two nested PCR and real-time PCR techniques were higher than that of microscopy examination (sensitivity, 100% versus 26.4%; kappa values, 0.2 to 0.5). Among the three regions, parasite-positive samples were highly detected in subjects from the Bago and Tanintharyi regions. Active surveillance of residents from regions of intense malaria transmission would reduce the risk of morbidity and mitigate transmission to the population in these areas of endemicity. Our data demonstrate that PCRbased molecular techniques are more efficient than microscopy for nationwide surveillance of malaria in countries where malaria is endemic.

BackgroundEmergence of artemisinin-resistant malaria in Southeast Asian countries threatens the global control of malaria. Although K13 kelch propeller has been assessed for artemisinin resistance molecular marker, most of the mutations need to be validated. In this study, artemisinin resistance was assessed by clinical and molecular analysis, including k13 and recently reported markers, pfarps10, pffd and pfmdr2.MethodsA prospective cohort study in 1160 uncomplicated falciparum patients was conducted after treatment with artemisinin-based combination therapy (ACT), in 6 sentinel sites in Myanmar from 2009 to 2013. Therapeutic efficacy of ACT was assessed by longitudinal follow ups. Molecular markers analysis was done on all available day 0 samples.ResultsTrue recrudescence treatment failures cases and day 3 parasite positivity were detected at only the southern Myanmar sites. Day 3 positive and k13 mutants with higher prevalence of underlying genetic foci predisposing to become k13 mutant were detected only in southern Myanmar since 2009 and comparatively fewer mutations of pfarps10, pffd, and pfmdr2 were observed in western Myanmar. K13 mutations, V127M of pfarps10, D193Y of pffd, and T448I of pfmdr2 were significantly associated with day 3 positivity (OR: 6.48, 3.88, 2.88, and 2.52, respectively).ConclusionsApart from k13, pfarps10, pffd and pfmdr2 are also useful for molecular surveillance of artemisinin resistance especially where k13 mutation has not been reported. Appropriate action to eliminate the resistant parasites and surveillance on artemisinin resistance should be strengthened in Myanmar. Trial registration This study was registered with ClinicalTrials.gov, identifier NCT02792816.

Background The malaria burden of Myanmar still remains high within the Greater Mekong Subregion of Southeast Asia. An important indicator of progress towards malaria elimination is the prevalence of parasite infections in endemic populations. Information about malaria epidemiology is mostly derived from reports of confirmed acute malaria cases through passive case detection, whereas the prevalence of baseline subclinical malaria infections is much less known. Methods In this study, cross-sectional surveys were conducted during the rainy season of 2017 in four townships (Bilin, Thabeikkyin, Banmauk and Paletwa) of Myanmar with divergent annual malaria incidences. A total of 1991 volunteers were recruited from local villages and Plasmodium subclinical infections were estimated by light microscopy (LM), rapid diagnostic tests (RDTs) and nested PCR. The nested PCR analysis was performed with a modified pooling strategy that was optimized based on an initial estimate the infection prevalence. Results The overall malaria infection prevalence based on all methods was 13.9% (277/1991) and it differed drastically among the townships, with Paletwa in the western border having the highest infection rate (22.9%) and Thabeikkyin in central Myanmar having the lowest (3.9%). As expected, nested PCR was the most sensitive and identified 226 (11.4%) individuals with parasite infections. Among the parasite species, Plasmodium vivax was the most prevalent in all locations, while Plasmodium falciparum also accounted for 32% of infections in the western township Paletwa. Two RDTs based on the detection of the hrp2 antigen detected a total of 103 P. falciparum infections, and the ultrasensitive RDT detected 20% more P. falciparum infections than the conventional RDT. In contrast, LM missed the majority of the subclinical infections and only identified 14 Plasmodium infections. Conclusions Cross-sectional surveys identified considerable levels of asymptomatic Plasmodium infections in endemic populations of Myanmar with P. vivax becoming the predominant parasite species. Geographical heterogeneity of subclinical infections calls for active surveillance of parasite infections in endemic areas. The pooling scheme designed for nested PCR analysis offers a more practical strategy for large-scale epidemiological studies of parasite prevalence. Such information is important for decision-makers to put forward a more realistic action plan for malaria elimination. Electronic supplementary material The online version of this article (10.1186/s13071-019-3330-1) contains supplementary material, which is available to authorized users.

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The conversion of biomass waste products to valuable products like cellulose hydrogel films is important in cell regeneration. In this study, the various biomass wastes: thanaka heartwood (TH), sugarcane bagasse (SB) and rice straw (RS) were used as cellulose resources. They were chemically treated using acid and alkali to obtain cellulose fibers. The yield percent of cellulose fibers depends on the nature of biomass materials. Scanning Electron Microscope (SEM), X-ray Diffraction (XRD) and Fourier Transform Infrared Spectroscopy (FTIR) analyses showed that the amount of lignin and hemicellulose from these samples were successfully reduced by chemical treatment. Cellulose fibers were treated using the dimethylacetamide/lithium chloride (DMAc/LiCl) system to obtain cellulose hydrogel solutions. Following this, the cellulose hydrogel films were prepared employing the phase inversion method without cross-linker. These films were transparent and flexible. In the present study, water retainable property and viscoelasticity of cellulose hydrogel films were measured. Antimicrobial activity tests of cellulose solutions have been carried out to be utilized to hydrogel films for biomedical application.

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