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Background: Joint efforts by government and non-government organizations have helped to reduce malaria in Bangladesh and set the country on a clear path to eventual malaria elimination. However, achieving that goal would be challenging without a comprehensive understanding of vector bionomics. Methods: Targeted capturing of Anopheles mosquitoes over a rainy season, utilizing specific sampling methods, including human landing catches (HLCs), CDC-light traps (CDC-LTs), and pyrethrum spray catches (PSCs) were aimed to characterize entomological drivers of transmission in four sites of Bandarban, Bangladesh. Results: Molecular characterization of a subset of 4637 mosquitoes has demonstrated the presence of at least 17 species whose capture rates were representative of the rainy season. Species compositions and bionomic traits did not vary between sites with Anopheles maculatus having the highest landing rate by HLCs and Anopheles vagus having the highest capture rate with CDC-LTs. Interestingly, Anopheles species compositions and capture rates varied significantly (p < 0.05) for An. vagus, between HLCs and its often-used proxy—CDC-LTs- suggesting impacts on downstream analysis. CDC-LTs capture rates demonstrated differing compositions with indoor and outdoor biting rates. For example, Anopheles nigerrimus and Anopheles nivipes were more endophagic by HLCs and more exophagic by CDC-LTs. The use of a cow-baited CDC-LT also demonstrated significantly different results when compared to a human-baited CDC-LT considering the high degree of anthropophily in these species. The exception to both zoophily and indoor resting was An. vagus, which demonstrated both anthropophily and high resting rates indoors—pointing to this species being a possible primary vector at this site. Conclusion: A diverse Anopheles fauna in Bandarban has been confirmed through molecular methods, highlighting the potential impact of sampling techniques. Given the complexity of the local ecosystem, a better understanding of mosquito behaviour and ecology is required to achieve the goal of malaria elimination in Bangladesh. [ABSTRACT FROM AUTHOR]

Background: Among 13 endemic districts, the Chittagong Hill Tracts bear more than 90% of Bangladesh's malaria burden. Despite the private sector's prominence in rural healthcare, its role in malaria management remains underutilized. This study aimed to strategize leveraging the for-profit private sector, such as diagnostic and treatment centers, to bolster national malaria surveillance and control, advancing Bangladesh toward malaria elimination by 2030. Methods: This mixed-method study commenced with a questionnaire-based cross-sectional survey followed by selected focused group discussions (FGDs) among the participants. Three FGDs were held with the for-profit service providers so that further insights and qualitative viewpoints of them can be utilized in situation analysis. Based on the endemicity and strategic priorities, a comprehensive mapping of private for-profit facilities from the regions comprising 15 sub-districts across 8 chosen districts (7 malaria endemic districts and the rest non-endemic districts) was created. For the non-endemic zone, the sub-districts were selected based on their proximity to an area with high malaria transmission. Results: Among the 104 representative participants, majority were male (n = 92, 88.5%), had a diploma in their respective fields (n = 53, 51%) and were involved either in laboratory work (n = 49, 47.1%) or as owners/managers of health centers (n = 41, 39.4%). The selected health facilities were close to the corresponding Upazila Health Complexes (mean distance 2.8 km), but were distantly located from the designated district hospitals (mean distance 48.9 km). The main sources of RDT kits (62.3%) and anti-malarial drugs (63.2%) were local wholesale markets. A large share of the corresponding facilities neither provided malaria treatment services (81.7%) nor worked with the NMEP (93.3%). Conclusions: This study highlights challenges and recommendations for engaging private for-profit health facilities in Bangladesh's malaria elimination efforts. The identified challenges include low-quality RDTs, staff shortages, and inadequate capacity building. Recommendations emphasize effective training, stakeholder interaction, and enhanced oversight for successful malaria control efforts. [ABSTRACT FROM AUTHOR]

Background: Bangladesh has reduced malaria incidence and mortality by over 75% between 2010 and 2020. Widespread long-lasting insecticidal net (LLIN) distribution and use is one of the measures responsible for this success. Recalcitrant malaria hotspots within the Chittagong Hill Tracts districts suggest important drivers of malaria risk may remain uncharacterized. Methods: Towards understanding how household-level human behaviour impacts exposure to mosquitoes, parallel human landing catches and human behavioural observations were conducted in four households for 6 months (May–October) over the rainy season in the Bandarban District. Analysis quantifies spatiotemporal human behaviour-adjusted exposure to Anopheles with and without LLINs. Results: This small-scale operational study demonstrates that human spatial and temporal presence along with LLIN use drives exposure to Anopheles. Though the four households had both outdoor and indoor exposure, especially in the evening (1800–2000 h) and early morning (0400–0500 h), data points to household-based heterogeneity in malaria exposure even with similar LLIN access. Conclusion: Incorporating human behaviour into exposure estimates can be used to understand the efficacy and limitations of local vector control strategies and identify gaps in protection, as well as where present intervention strategies may be optimized. [ABSTRACT FROM AUTHOR]

Background: Malaria remains endemic in Bangladesh, with the majority of cases occurring in forested, mountainous region in the Chittagong Hill Tracts (CHT). This area is home to Bengali and diverse groups of indigenous people (Pahari) residing largely in mono-ethnic villages. Methods: 1002 individuals of the 9 most prominent Pahari and the Bengali population were randomly selected and screened by RDT and qPCR. Parasites were genotyped by msp2 and deep sequencing of 5 amplicons (ama1-D3, cpmp, cpp, csp, and msp7) for Plasmodium falciparum (n = 20), and by microsatellite (MS) typing of ten loci and amplicon sequencing of msp1 for Plasmodium vivax (n = 21). Population structure was analysed using STRUCTURE software. Identity-by-state (IBS) was calculated as a measure of parasite relatedness and used to generate relatedness networks. Results: The prevalence of P. falciparum and P. vivax infection was 0.7% by RDT (P. falciparum 6/1002; P. vivax 0/1002, mixed: 1/1002) and 4% by qPCR (P. falciparum 21/1002; P. vivax 16/1002, mixed: 5/1002). Infections were highly clustered, with 64% (27/42) of infections occurring in only two Pahari groups, the Khumi and Mro. Diversity was high; expected heterozygosity was 0.93 for P. falciparum and 0.81 for P. vivax. 85.7% (18/21) of P. vivax and 25% (5/20) of P. falciparum infections were polyclonal. No population structure was evident for either species, suggesting high transmission and gene flow among Pahari groups. Conclusions: High subclinical infection prevalence and genetic diversity mirror ongoing transmission. Control activities should be specifically directed to Pahari groups at greatest risk. [ABSTRACT FROM AUTHOR]

Primaquine and tafenoquine are the only licensed drugs with activity against Plasmodium vivax hypnozoites but cause haemolysis in patients with glucose–6–phosphate dehydrogenase (G6PD) deficiency. Malaria also causes haemolysis, leading to the replacement of older erythrocytes with low G6PD activity by reticulocytes and young erythrocytes with higher activity. Aim of this study was to assess the impact of acute malaria on G6PD activity. Selected patients with uncomplicated malaria were recruited in Bangladesh (n = 87), Indonesia (n = 75), and Ethiopia (n = 173); G6PD activity was measured at the initial presentation with malaria and a median of 176 days later (range 140 to 998) in the absence of malaria. Among selected participants (deficient participants preferentially enrolled in Bangladesh but not at other sites) G6PD activity fell between malaria and follow up by 79.1% (95%CI: 40.4 to 117.8) in 6 participants classified as deficient (<30% activity), 43.7% (95%CI: 34.2 to 53.1) in 39 individuals with intermediate activity (30% to <70%), and by 4.5% (95%CI: 1.4 to 7.6) in 290 G6PD normal (≥70%) participants. In Bangladesh and Indonesia G6PD activity was significantly higher during acute malaria than when the same individuals were retested during follow up (40.9% (95%CI: 33.4–48.1) and 7.4% (95%CI: 0.2 to 14.6) respectively), whereas in Ethiopia G6PD activity was 3.6% (95%CI: -1.0 to -6.1) lower during acute malaria. The change in G6PD activity was apparent in patients presenting with either P. vivax or P. falciparum infection. Overall, 66.7% (4/6) severely deficient participants and 87.2% (34/39) with intermediate deficiency had normal activities when presenting with malaria. These findings suggest that G6PD activity rises significantly and at clinically relevant levels during acute malaria. Prospective case-control studies are warranted to confirm the degree to which the predicted population attributable risks of drug induced haemolysis is lower than would be predicted from cross sectional surveys. Author summary: Plasmodium vivax forms dormant liver stages in the human host that reactivate weeks to months after the first infection and cause significant morbidity and mortality in affected populations. The group of 8-aminoquinolines are the only class of licensed drugs that remove these liver stages from the human host but are contra-indicated in patients with low activities of the glucose-6-phosphate dehydrogenase enzyme (G6PD). The WHO therefore recommends testing G6PD activity prior to treatment to exclude individuals with low activities from standard treatment. We enrolled 335 patients with malaria in Bangladesh, Indonesia, and Ethiopia and measured G6PD activity in all participants. All participants were followed up and a second G6PD measurement was collected between 6 and 33 months after enrolment if participants were free of malaria. When comparing both measurements, G6PD activity was 10% higher during malaria. The increase in G6PD activity during malaria is probably triggered by the Plasmodium infection, the observed change in G6PD activity may alter the risk profile of standard malaria treatment with 8-aminoquinolines. [ABSTRACT FROM AUTHOR]

Background: Glucose-6-phosphate dehydrogenase (G6PD) activity is dependent upon G6PD genotype and age of the red blood cell (RBC) population, with younger RBCs having higher activity. Peripheral parasitemia with Plasmodium spp. induces hemolysis, replacing older RBCs with younger cells with higher G6PD activity. This study aimed to assess whether G6PD activity varies between individuals with and without malaria or a history of malaria.Methods and Findings: Individuals living in the Chittagong Hill Tracts of Bangladesh were enrolled into 3 complementary studies: (i) a prospective, single-arm clinical efficacy trial of patients (n = 175) with uncomplicated malaria done between 2014 and 2015, (ii) a cross-sectional survey done between 2015 and 2016 (n = 999), and (iii) a matched case-control study of aparasitemic individuals with and without a history of malaria done in 2020 (n = 506). G6PD activity was compared between individuals with and without malaria diagnosed by microscopy, rapid diagnostic test (RDT), or polymerase chain reaction (PCR), and in aparasitemic participants with and without a history of malaria. In the cross-sectional survey and clinical trial, 15.5% (182/1,174) of participants had peripheral parasitemia detected by microscopy or RDT, 3.1% (36/1,174) were positive by PCR only, and 81.4% (956/1,174) were aparasitemic. Aparasitemic individuals had significantly lower G6PD activity (median 6.9 U/g Hb, IQR 5.2-8.6) than those with peripheral parasitemia detected by microscopy or RDT (7.9 U/g Hb, IQR 6.6-9.8, p < 0.001), but G6PD activity similar to those with parasitemia detected by PCR alone (submicroscopic parasitemia) (6.1 U/g Hb, IQR 4.8-8.6, p = 0.312). In total, 7.7% (14/182) of patients with malaria had G6PD activity < 70% compared to 25.0% (248/992) of participants with submicroscopic or no parasitemia (odds ratio [OR] 0.25, 95% CI 0.14-0.44, p < 0.001). In the case-control study, the median G6PD activity was 10.3 U/g Hb (IQR 8.8-12.2) in 253 patients with a history of malaria and 10.2 U/g Hb (IQR 8.7-11.8) in 253 individuals without a history of malaria (p = 0.323). The proportion of individuals with G6PD activity < 70% was 11.5% (29/253) in the cases and 15.4% (39/253) in the controls (OR 0.7, 95% CI 0.41-1.23, p = 0.192). Limitations of the study included the non-contemporaneous nature of the clinical trial and cross-sectional survey.Conclusions: Patients with acute malaria had significantly higher G6PD activity than individuals without malaria, and this could not be accounted for by a protective effect of G6PD deficiency. G6PD-deficient patients with malaria may have higher than expected G6PD enzyme activity and an attenuated risk of primaquine-induced hemolysis compared to the risk when not infected. [ABSTRACT FROM AUTHOR]

The proportion of Plasmodium vivax malaria among all malarias is increasing worldwide. Treatment with 8-aminoquinolines remain the only radical cure. However, 8-aminoquinolines can cause severe hemolysis in glucose-6-phosphate dehydrogenase (G6PD) deficient patients. The population of the multi-ethnic Chittagong Hill Tracts (CHT) carry the highest malaria burden within Bangladesh. As in many countries the national treatment guidelines recommend 8-aminoquinoline based radical cure without routine G6PD deficiency (G6PDd) testing to guide treatment. Aim of this study was to determine the need for routine testing within a multi-ethnic population by assessing the prevalence of G6PDd among the local population. Participants from 11 ethnicities were randomly selected and malaria status was assessed by microscopy, rapid diagnostic test (RDT) and polymerase chain reaction (PCR). G6PD status was determined by spectrophotometry and G6PD genotyping. The adjusted male median (AMM) was defined as 100% G6PD activity, participants were categorized as G6PD deficient (<30% activity), G6PD intermediate (30% to 70% activity) or G6PD normal (>70% activity). Median G6PD activities between ethnicities were compared and the association between G6PD activity and malaria status was assessed. 1002 participants were enrolled and tested for malaria. G6PD activity was measured by spectrophotometry in 999 participants and host G6PD genotyping undertaken in 323 participants. Seven participants (0.7%) had peripheral parasitaemia detected by microscopy or RDT and 42 by PCR (4.2%). Among 106 participants (32.8%) with confirmed genotype, 99 (93.4%) had the Mahidol variant. The AMM was 7.03U/gHb with 90 (9.0%) G6PD deficient participants and 133 (13.3%) with intermediate G6PD activity. Median G6PD activity differed significantly between ethnicities (p<0.001), proportions of G6PD deficient individuals ranged from 2% to 26% but did not differ between participants with and without malaria. The high G6PDd prevalence and significant variation between ethnicities suggest routine G6PDd testing to guide 8-aminoquinoline based radical in the CHT and comparable settings. Author summary: The Plasmodium vivax malaria parasite is a major public health burden in many parts of the Asia-Pacific and Americas. Primaquine-based radical cure is the only available treatment that effectively removes P. vivax from the human host but can cause severe side effects in individuals with glucose-6-phosphate dehydrogenase (G6PD) deficiency. The WHO recommends testing for G6PD deficiency to guide treatment, but this is not done on a routine basis in many countries. The aim of this study was to determine the importance of routine testing in multi-ethnic populations. The study was conducted in a multi-ethnic population in the Chittagong Hill Tracts (Bangladesh), which carries the highest burden of malaria within the country. We enrolled 1002 participants from 11 major ethnicities within the area and assessed the prevalence of G6PD deficiency by phenotype and genotype. Based on phenotype 9.0% of the population were not eligible for standard primaquine based radical cure, however numbers varied significantly between ethnicities, ranging from 2% to 26%. In 93% of cases where a genotype was identified, the severe Mahidol G6PD variant was found. Our findings highlight the importance of routine G6PD testing prior to primaquine based radical cure in multi-ethnic populations. [ABSTRACT FROM AUTHOR]

• Ivermectin, an FDA-approved anti-parasitic agent, was found to be an inhibitor of SARS-CoV-2 replication in the laboratory. • Ivermectin may be effective for the treatment of early-onset mild COVID-19 in adult patients. • Early viral clearance of SARS-CoV-2 was observed in ivermectin treated patients. • Remission of fever, cough and sore throat did not differ among treatment groups. No severe adverse event was observed. • Larger trials will be needed to confirm these preliminary findings. Ivermectin, a US Food and Drug Administration-approved anti-parasitic agent, was found to inhibit severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) replication in vitro. A randomized, double-blind, placebo-controlled trial was conducted to determine the rapidity of viral clearance and safety of ivermectin among adult SARS-CoV-2 patients. The trial included 72 hospitalized patients in Dhaka, Bangladesh, who were assigned to one of three groups: oral ivermectin alone (12 mg once daily for 5 days), oral ivermectin in combination with doxycycline (12 mg ivermectin single dose and 200 mg doxycycline on day 1, followed by 100 mg every 12 h for the next 4 days), and a placebo control group. Clinical symptoms of fever, cough, and sore throat were comparable among the three groups. Virological clearance was earlier in the 5-day ivermectin treatment arm when compared to the placebo group (9.7 days vs 12.7 days; p = 0.02), but this was not the case for the ivermectin + doxycycline arm (11.5 days; p = 0.27). There were no severe adverse drug events recorded in the study. A 5-day course of ivermectin was found to be safe and effective in treating adult patients with mild COVID-19. Larger trials will be needed to confirm these preliminary findings. [ABSTRACT FROM AUTHOR]

Background: Glucose-6-Phosphate dehydrogenase (G6PD) deficiency is the most common enzymopathy worldwide, no reliable bedside diagnostic tests to quantify G6PD activity exist. This study evaluated two novel quantitative G6PD diagnostics. Methods: Participants with known G6PD activity were enrolled in Bangladesh. G6PD activity was measured by spectrophotometry, Biosensor (BS; AccessBio/CareStart, USA) and STANDARD G6PD (SG; SDBiosensor, ROK). G6PD activity was measured repeatedly in a subset of samples stored at room temperature and 4°C. Results: 158 participants were enrolled, 152 samples tested by BS, 108 samples by SG and 102 samples were tested by all three methods. In comparison to spectrophotometry BS had sensitivity and specificity of 72% (95%CI: 53–86) and 100% (95%CI: 97–100) at 30% cut off respectively, while SG had a sensitivity of 100% (95%CI: 88–100) and specificity of 97% (95%CI: 91–99) at the same cut off. The sensitivity and specificity at 70% cut off activity were 71% (95%CI: 59–82) and 98% (95%CI, 92–100) respectively for BS and 89% (95%CI: 77–96) and 93% (95%CI: 83–98) respectively for SG. When an optimal cut-off was applied the sensitivity of the BS at 70 cut off rose to 91% [95%CI: 80–96] and specificity to 82% [95%CI: 83–89]; a diagnostic accuracy comparable to that of the SG (p = 0.879). G6PD activity dropped significantly (-0.31U/gHb, 95%CI: -0.61 to -0.01, p = 0.022) within 24 hours in samples stored at room temperature, but did not fall below 90% of baseline activity until day 13 (-0.87U/gHb, 95%CI: (-1.11 to -0.62), p<0.001). Conclusion: BS and SG are the first quantitative diagnostics to measure G6PD activity reliably at the bedside and represent suitable alternatives to spectrophotometry in resource poor settings. If samples are stored at 4°C, G6PD activity can be measured reliably for at least 7 days after sample collection. [ABSTRACT FROM AUTHOR]