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Mapping asymptomatic malaria infections, which contribute to the transmission reservoir, is important for elimination programs. This analysis compared the spatiotemporal patterns of symptomatic and asymptomatic Plasmodium falciparum malaria infections in a cohort study of ∼25,000 people living in a rural hypoendemic area of about 179 km2 in a small area of the Chittagong Hill Districts of Bangladesh. Asymptomatic infections were identified by active surveillance; symptomatic clinical cases presented for care. Infections were identified by a positive rapid diagnostic test and/or microscopy. Fifty-three subjects with asymptomatic P. falciparum infection were compared with 572 subjects with symptomatic P. falciparum between mid-October 2009 and mid-October 2012 with regard to seasonality, household location, and extent of spatial clustering. We found increased spatial clustering of symptomatic compared with asymptomatic infections, and the areas of high intensity were only sometimes overlapping. Symptomatic cases had a distinct seasonality, unlike asymptomatic infections, which were detected year-round. In a comparison of 42 symptomatic Plasmodium vivax and 777 symptomatic P. falciparum cases from mid-October 2009 through mid-March 2015, we found substantial spatial overlap in areas with high infection rates, but the areas with the greatest concentration of infection differed. Detection of both symptomatic P. falciparum and symptomatic P. vivax infections was greater during the May-to-October high season, although a greater proportion of P. falciparum cases occurred during the high season compared with P. vivax. These findings reinforce that passive malaria surveillance and treatment of symptomatic cases will not eliminate the asymptomatic reservoirs that occur distinctly in time and space.

The key concern of this paper is to bring forth a contemporary estimation of the impact of the ongoing COVID-19 pandemic on remittance inflows in Bangladesh as well as to find out the scenario of whether the migration and exchange rate have impacted on the remittance inflows in Bangladesh based on the monthly data from January 2008 to December 2021. By introducing dummy variable in the Autoregressive Distributed Lag (ARDL) bound testing approach, it is found that the ongoing COVID-19 pandemic has a strong positive impact on the remittance inflows in Bangladesh in the long-run. Besides, there is a positive impact of exchange rate on remittance inflows in the long-run while a negative relationship between the remittance inflows and migration in the long-run in Bangladesh. For the healthiness of the model, various diagnostic tests along with normality and stability test were performed over the period.

The aim of the study was to explore the antioxidant and free radical scavenging activity of bark of Dillenia indica L. The methanolic extract (CME) of coarse powder of the dried bark was fractionated with pet-ether (PETF), chloroform (CHF), and water (AQF) and each fraction was investigated for antioxidant and free radical potentials. The phenolic contents of CME, CHF, PETF and AQF were found to be 90.2, 171.1, 52.1 and 158.1 and flavonoid contents 182.6, 340.2, 285.9, and 362.6 mg of GAE/g of dried extract, respectively. The total antioxidant activity of CME, PETF, CHF, AQF and standard catechin in terms of absorbance were 0.373, 0.707, 0.88, 1.051 and 0.804, respectively at 160 μg/ml concentration indicating AQF possessing the highest total antioxidant activity. In DPPH radical scavenging activity, the AQF and CHF showed potential radical scavenging activity followed by CME and PETF with IC50 values of 1.5, 2.5, 23 and 61 μg/ml, respectively, whereas standard ascorbic acid showed IC50 at 8 μg/ml. Among the extractives, AQF and CHF exhibited potent hydroxyl radical scavenging activity with IC50 values of 49.0 and 42 μg/ml followed by CME and PETF with IC50 of 86 and 168 μg/ml, respectively. In ferric-reducing antioxidant assay, AQF, CHF and CME (absorbance 2.262, 2.418 and 2.157, respectively) showed higher activity than that of standard (1.793) followed by PETF (absorbance 0.593). Since polyphenols like flavonoids play a vital role in controlling antioxidants, polyphenol rich extracts are potent source of antioxidants. Our data showed that the chloroform fraction of the bark of D. indica provided highest polyphenols and antioxidant activities, hence, can be used further as a source of natural antioxidants. Bangladesh Pharmaceutical Journal 25(1): 38-43, 2022 (January)

This study seeks to assess the effects of the components of FDI inflows on GDP growth in Bangladesh covered the years 1997 to 2021. For this, three components of FDI (equity capital, reinvested earnings and intra company loans) along with labor force and trade openness have used in this analysis. By employing ARDL Bound Test, the coefficients of reinvested earnings and intra company loans provide a significantly positive relationship with GDP growth both in the short run and the long run. Whereas, the coefficient of equity capital has positive but insignificant impact on GDP growth in the long run. Besides, labor force and trade openness has positive and significant impact on GDP growth. Several diagnostics tests demonstrate that the model is normal, stable, and there is no serial autocorrelation or heteroscedasticity. The study suggests that FDI inducing policies will enhance the economic growth, mitigate the effects of the COVID-19 pandemic and meet up the sustainable development goals (SDG), {"references":["Agrawal, G., & Khan, M. A. (2011). Impact of FDI on GDP: A comparative study of China and India. International Journal of Business and Management, 6(10), 71.","Ahamad, M. G., Tanin, F., & Ahmed, Z. U. (2010). Does FDI intensify Economic Growth? Empirics from Bangladesh","Ahamed, M. G., & Tanin, F. (2010). Determinants of, and the Relationship between FDI and Economic Growth in Banglades","Asaduzzaman, M. (2019). FDI as an Opportunity for Economic growth of Bangladesh: A VECM Analysis. ERN: Other Development Economics: Macroeconomic Issues in Developing Economies (Topic).","Baklouti, N., & Boujelbene, Y. (2016). Foreign Direct Investment-Economic Growth Nexus. Acta Universitatis Danubius: Oeconomica, 12(2).","Bashir, T., Mansha, A., Zulfiqar, R., & Riaz, R. (2014). Impact of FDI on economy growth: a comparison of South Asian States & China. European Scientific Journal, 10(1)."]}

The study aims to assess the cytotoxic activity of the methanolic extract (CME) and various fractions from the bark of Dillenia indica L (Family: Dilleniaceae) using brine shrimp lethality bioassay and sedative activities using hole cross, open field, and elevated-plus maze (EPM) test in Swiss albino mice. In brine shrimp assay, the LC50 for CME, pet-ether (PETF), chloroform (CHF) and aqueous (AQF) fraction were found to be 110, 24.55, 85 and 14.45 μg/ml, respectively, indicating significant cytotoxicity of PETF and AQF when compared to the standard vincristine sulfate (7.5 μg/ml). In open field test, the number of movements per min (after 120 min) was 40.90, 12.43, 5.45, 3.66, and 29.74 for control, standard diazepam, CME, CHF and AQF, respectively, indicating strong activity of the chloroform soluble fraction compared to the other test samples of D. indica. Similar data was observed in hole cross test where the number of movements per minute after 120 min were 3.60, 5.56, 4.77, and 7.99 for the standard, CME, CHF and AQF, respectively. In EPM test, the CME showed a significant decreased percentage of entries of mice into the open arms of EPM as well as the percentage of time spent in the open arms. The result indicates that the CHF significantly suppressed the locomotor activity than that of methanol and aqueous fractions. These findings will be helpful for bioassay-guided isolation of active principles responsible for cytotoxicity and sedative activities. Bangladesh Pharmaceutical Journal 24(2): 105-110, 2021

To understand the effect of post-harvest good handling practices on prawn(Macrobrachiumrosenbergii) quality, data were collected from stakeholders involved indistribution chain by semi-structured questionnaire, focus group discussion and transectwalking at Kishoreganj and Mymensingh. Most used containers were split bamboo basket(39%), split bamboo basket with polythene lining (18%), plastic crate (12%), styrofoamcrate (8%) and rectangular metal container (12%). 15%, 25%, 10%, 100% and 7% largeprawns were water washed and 9%, 35%, 22%, 100%, 60% large prawns were icedimmediately after harvest, later in fishing trip, immediately after landing, at wholesalehouse before transportation and during retail sale, respectively. Bacterial counts of waterused for ice preparation, ice crushed mechanically and on soil floor collected from BhairabBazar and Karimganj were 6.58±1.87×103, 4.77±0.19×102, 4.12±2.06×103 cfu/ml and4.82±1.56×102, 6.01±1.61×101, 6.90±1.61×102 cfu/ml, respectively. Ice melted watercollected after unpacking prawn containers at Mymensingh, transported from BhairabBazar and Karimganj, had 5.90±1.95×107 and 6.32±2.06×108 cfu/ml bacterial counts,respectively; indicated unhygienic handling environments. However, existing post-harvesthandling practices produce prawns acceptable for consumers as sensory assessment forprawns showed the quality defect points of 1.0 (Excellent), 2.1 (Good), 2.3 (Good) and 2.9(Good) at harvesting, landing, wholesale and retail shop, respectively. Res. Agric., Livest. Fish.7(2): 321-328, August 2020

Maturation rate of malaria parasites within red blood cells (RBC) can be influenced by host nutrient status or circadian rhythm. Here, we observed in mice that systemic host inflammation, induced by lipopolysaccharide (LPS) conditioning or ongoing acute malaria infection, slowed the progression of a single cohort of parasites from one generation of RBC to the next. LPS-conditioning and acute infection both triggered substantial changes to the metabolomic composition of plasma in which parasites circulated. This altered plasma directly slowed parasite maturation in a manner that could not be rescued by supplementation, consistent with the presence of inhibitory factors. Single-cell transcriptomic assessment of mixed parasite populations, exposed to a short period of systemic host inflammation in vivo, revealed specific impairment in the transcriptional activity and translational capacity of trophozoites compared to rings or schizonts. Thus, we provide in vivo evidence of transcriptomic and phenotypic plasticity of asexual blood-stage Plasmodium parasites when exposed to systemic host inflammation.

A major mechanism of host-mediated control of blood-stage Plasmodium infection is thought to be removal of parasitized red blood cells (pRBCs) from circulation by the spleen or phagocytic system. The rate of parasite removal is thought to be further increased by anti-malarial drug treatment, contributing to the effectiveness of drug therapy. It is difficult to directly compare pRBC removal rates in the presence and absence of treatment, since in the absence of treatment the removal rate of parasites is obscured by the extent of ongoing parasite proliferation. Here, we transfused a single generation of fluorescently-labelled Plasmodium berghei pRBCs into mice, and monitored both their disappearance from circulation, and their replication to produce the next generation of pRBCs. In conjunction with a new mathematical model, we directly estimated host removal of pRBCs during ongoing infection, and after drug treatment. In untreated mice, pRBCs were removed from circulation with a half-life of 15.1 h. Treatment with various doses of mefloquine/artesunate did not alter the pRBC removal rate, despite blocking parasite replication effectively. An exception was high dose artesunate, which doubled the rate of pRBC removal (half-life of 9.1 h). Phagocyte depletion using clodronate liposomes approximately halved the pRBC removal rate during untreated infection, indicating a role for phagocytes in clearance. We next assessed the importance of pRBC clearance for the decrease in the parasite multiplication rate after high dose artesunate treatment. High dose artesunate decreased parasite replication ∼46-fold compared with saline controls, with inhibition of replication contributing 23-fold of this, and increased pRBC clearance contributing only a further 2.0-fold. Thus, in our in vivo systems, drugs acted primarily by inhibiting parasite replication, with drug-induced increases in pRBC clearance making only minor contributions to overall drug effect.

The artemisinins are the first-line therapy for severe and uncomplicated malaria, since they cause rapid declines in parasitemia after treatment. Despite this, in vivo mechanisms underlying this rapid decline remain poorly characterised. The overall decline in parasitemia is the net effect of drug inhibition of parasites and host clearance, which competes against any ongoing parasite proliferation. Separating these mechanisms in vivo was not possible through measurements of total parasitemia alone. Therefore, we employed an adoptive transfer approach in which C57BL/6J mice were transfused with Plasmodium berghei ANKA strain-infected, fluorescent red blood cells, and subsequently drug-treated. This approach allowed us to distinguish between the initial drug-treated generation of parasites (Gen0), and their progeny (Gen1). Artesunate efficiently impaired maturation of Gen0 parasites, such that a sufficiently high dose completely arrested maturation after 6h of in vivo exposure. In addition, artesunate-affected parasites were cleared from circulation with a half-life of 6.7h. In vivo cell depletion studies using clodronate liposomes revealed an important role for host phagocytes in the removal of artesunate-affected parasites, particularly ring and trophozoite stages. Finally, we found that a second antimalarial drug, mefloquine, was less effective than artesunate at suppressing parasite maturation and driving host-mediated parasite clearance. Thus, we propose that in vivo artesunate treatment causes rapid decline in parasitemia by arresting parasite maturation and encouraging phagocyte-mediated clearance of parasitised RBCs.

The hybrid arrangement of the power system is becoming famous in the latest days on account of its gain of sustainable combination to the classical strength grid. Hybrid power systems with renewable sources can provide potency, reliability, and security while reducing operational costs. It is advantageous to the analyst, even after a detailed solution has been performed. If the detailed stability case at the expected clearing time is unstable, the critical clearing time indicates the improvement necessary to achieve stability. A review of the hybrid power system and a comprehensive analysis of critical clearing time in transient stability assessment are performed and presented here. For elaborated analysis, IEEE 30 bus test power system has been adopted and revised for this distinct study. The modified hybrid power system subsist of the wind turbine, solar PV array with the energy storage mechanism and conventional diesel generators to study the critical clearing time for the transient stability assessment. The hybrid wind-solar-diesel wattage power system was sculptured in ETAP simulation software. The alteration in rotor angle of the machines after a three-phase fault is considered for various cases and the details investigation are presented here.

Bangla Sign language (BdSL) is the communication language used by the deaf and dumb of Bangladesh. In this paper, we present an optimal approach to recognize BdSL in real-time. First, we have developed BdSLInfinite dataset, which consists of 2,000 images of 37 different signs. Using this dataset, a convolutional neural network (CNN) based model is trained using Xception architecture that achieves 98.93% accuracy over the test-set, with response time of 48.53 ms on average. To the best of our knowledge, our proposed method outperforms all existing BdSL recognition methods in terms of both accuracy and speed.

Malaria is an infectious disease caused by protozoan parasites of the genus Plasmodium. It remains a major cause of morbidity and deaths in many developing countries – an estimated 445,000 people died from malaria in 2016. The symptoms of malaria occur during the blood-stage of infection, and can vary from asymptomatic infection to life-threatening syndromes such as cerebral malaria. The disease severity often correlates with the number of blood-stage parasites in the body. It is likely that both host and parasite factors are involved in determining parasite growth kinetics in vivo. However, our understanding of these factors is limited. Given that an effective malaria vaccine currently remains elusive, and that resistance has emerged against the currently available anti-malarial drugs, it is important to identify new approaches for controlling the number of parasites in blood in vivo.I have used experimental mouse models of blood-stage Plasmodium infection to directly measure parasite maturation, clearance and replication rates in vivo. I observed that parasite control can be achieved in a number of ways including: (i) the use of anti-malarial drugs that inhibit or arrest parasite development within a red blood cell, (ii) the use of drugs that prevent parasites from progressing from one generation of red blood cells to another, (iii) by host phagocytes actively removing parasitised red blood cells, and (iv) by host-mediated impairment of parasite maturation within red blood cells.Next, I identified the mechanisms of antibody-mediated parasite control using P. yoelii 17XNL and P. chabuadi AS infection models. The experiments that I conducted demonstrated that the Plasmodium-specific antibodies in these systems provide robust protection against homologous re-challenge not by accelerating clearance of infected pRBC but by preventing asexually replicated parasites transitioning from one infected red blood cell to the others. This correlated with an inability of Plasmodium-specific IgG to bind to the surface of pRBC, despite showing its clear specificity for the parasite proteins. I also observed that the efficacy of antibody-mediated immunity depended on phagocytes, but not on the complement factors C3/C5. Finally, hundreds of Plasmodium-exported proteins, known collectively as the “exportome”, remodel host RBC, and yet the precise functions of many of these as well their ability to promote host interactions remain unclear. Using a high-throughput, barcode-based forward genetic screen in immunocompetent and immune-deficient mice, I screened 117 exportome-associated genes to understand their in vivo function and possible host-interaction. I demonstrated that 32 of these genes were essential for blood-stage growth, including 8 with no previous functional annotation. Further analysis revealed that 10 genes were required for growth in the presence of an intact immune system, which were not required for growth in immune-deficient mice. This study provides proof-of-principle that although parasite genes are not essential for blood-stage growth per se but they are required in combating the host immune responses.

Plasmodium parasites invade and multiply inside red blood cells (RBC). Through a cycle of maturation, asexual replication, rupture and release of multiple infective merozoites, parasitised RBC (pRBC) can reach very high numbers in vivo, a process that correlates with disease severity in humans and experimental animals. Thus, controlling pRBC numbers can prevent or ameliorate malaria. In endemic regions, circulating parasite-specific antibodies associate with immunity to high parasitemia. Although in vitro assays reveal that protective antibodies could control pRBC via multiple mechanisms, in vivo assessment of antibody function remains challenging. Here, we employed two mouse models of antibody-mediated immunity to malaria, P. yoelii 17XNL and P. chabaudi chabaudi AS infection, to study infection-induced, parasite-specific antibody function in vivo. By tracking a single generation of pRBC, we tested the hypothesis that parasite-specific antibodies accelerate pRBC clearance. Though strongly protective against homologous re-challenge, parasite-specific IgG did not alter the rate of pRBC clearance, even in the presence of ongoing, systemic inflammation. Instead, antibodies prevented parasites progressing from one generation of RBC to the next. In vivo depletion studies using clodronate liposomes or cobra venom factor, suggested that optimal antibody function required splenic macrophages and dendritic cells, but not complement C3/C5-mediated killing. Finally, parasite-specific IgG bound poorly to the surface of pRBC, yet strongly to structures likely exposed by the rupture of mature schizonts. Thus, in our models of humoral immunity to malaria, infection-induced antibodies did not accelerate pRBC clearance, and instead co-operated with splenic phagocytes to block subsequent generations of pRBC., Author summary Malaria occurs when Plasmodium parasites replicate inside red blood cells, with the number of parasitised cells (pRBC) correlating with disease severity. Antibodies are highly effective at controlling pRBC numbers in the bloodstream, and yet we know very little about how they function in vivo. Human in vitro studies predict that antibodies may function in a number of ways, including via phagocytes or different complement mechanisms. However, to date it has been challenging to explore how antibodies might control parasite numbers in vivo. Here, we have used a unique method in mice, where clearance and replication of a single cohort of pRBC was closely tracked in the presence of protective antibodies. Surprisingly, antibodies played no role whatsoever in accelerating the removal of pRBC. Instead, antibodies were highly effective at preventing parasites from progressing from one generation of pRBC to the next. This process partly depended on host phagocytes. However, we found no role for complement-mediated direct killing. Together, our in vivo data suggest in mouse models that naturally-acquired antibodies do not clear pRBC, and instead prevent transition from one red blood cell to the next.

While milk is well known to be a balanced diet with its high nutritional values, conversely milk and milk products may serve as potential substrate for the growth and proliferation of a range of microorganisms which in turn fatally influences mass public health. Current study attempted to examine the likelihood of microbial contamination within some common milk products consumed by the locality of the city of Dhaka, Bangladesh. All samples exhibited the presence of bacterial and fungal contamination within a range of 102-104 cfu/mL and 102-103 cfu/mL, respectively. Among specific pathogens, Staphylococcus spp. was noticed to be the predominant ones and was recovered from 9 samples out of 20 samples in a range of 102-103 cfu/mL. Klebsiella spp. and Vibrio spp. were found within 6 and 9 samples, respectively. Products were also found to be contaminated with Vibrio spp. Study of antibiotic susceptibility test revealed that all the pathogenic bacteria were resistant against most of the commonly used antibiotics of which several isolates showed multi-drug resistant (MDR) trait. Therefore, the presence of pathogenic bacteria with the drug-resistance property in tested milk and milk products overall imparted the necessity of maintaining standardized hygienic handling and processing means for better management of public health.Stamford Journal of Microbiology, Vol.5(1) 2015: 13-17

Hemoglobin E is largely confined to south and southeast Asia. The association between hemoglobin E (HbE) and malaria is less clear than that of hemoglobin S and C. As part of a malaria study in the Chittagong Hill Districts of Bangladesh, an initial random sample of 202 individuals showed that 39% and 49% of Marma and Khyang ethnic groups, respectively, were positive for either heterozygous or homozygous hemoglobin E. In this group, 6.4% were also found to be severely deficient and 35% mildly deficient for glucose-6-phosphate dehydrogenase (G6PD). In a separate Plasmodium falciparum malaria case–uninfected control study, the odds of having homozygous hemoglobin E (HbEE) compared with normal hemoglobin (HbAA) were higher among malaria cases detected by passive surveillance than age and location matched uninfected controls (odds ratio [OR] = 5.0, 95% confidence interval [CI] = 1.07–46.93). The odds of heterozygous hemoglobin E (HbAE) compared with HbAA were similar between malaria cases and uninfected controls (OR = 0.71, 95% CI = 0.42–1.19). No association by hemoglobin type was found in the initial parasite density or the proportion parasite negative after 2 days of artemether/lumefantrine treatment. HbEE, but not HbAE status was associated with increased passive case detection of malaria.

Severe malaria and associated high parasite burdens occur more frequently in humans lacking robust adaptive immunity to Plasmodium falciparum Nevertheless, the host may partly control blood-stage parasite numbers while adaptive immunity is gradually established. Parasite control has typically been attributed to enhanced removal of parasites by the host, although in vivo quantification of this phenomenon remains challenging. We used a unique in vivo approach to determine the fate of a single cohort of semisynchronous, Plasmodium berghei ANKA- or Plasmodium yoelii 17XNL-parasitized red blood cells (pRBCs) after transfusion into naive or acutely infected mice. As previously shown, acutely infected mice, with ongoing splenic and systemic inflammatory responses, controlled parasite population growth more effectively than naive controls. Surprisingly, however, this was not associated with accelerated removal of pRBCs from circulation. Instead, transfused pRBCs remained in circulation longer in acutely infected mice. Flow cytometric assessment and mathematical modeling of intraerythrocytic parasite development revealed an unexpected and substantial slowing of parasite maturation in acutely infected mice, extending the life cycle from 24 h to 40 h. Importantly, impaired parasite maturation was the major contributor to control of parasite growth in acutely infected mice. Moreover, by performing the same experiments in rag1-/- mice, which lack T and B cells and mount weak inflammatory responses, we revealed that impaired parasite maturation is largely dependent upon the host response to infection. Thus, impairment of parasite maturation represents a host-mediated, immune system-dependent mechanism for limiting parasite population growth during the early stages of an acute blood-stage Plasmodium infection.

Malaria is endemic in the Chittagong Hill Districts of southeastern Bangladesh. Previous epidemiological analyses identified the agricultural practice of jhum cultivation as a potential risk factor for malaria infection. We conducted qualitative interviews with jhum cultivators and surveillance workers to describe jhum cultivation and used demographic and malaria surveillance in two study unions from May of 2010 to August of 2012 to better understand the relationship between jhum cultivation and malaria infection. Qualitative interviews revealed that jhum cultivation is conducted on remote, steep hillsides by ethnic tribal groups. Quantitative analyses found that adult jhum cultivators and individuals who live in the same residence had significantly higher incidence rates of symptomatic Plasmodium falciparum infection compared with non-cultivators. These results confirm that jhum cultivation is an independent risk factor for malaria infection and underscore the need for malaria testing and treatment services to reach remote populations in the Chittagong Hill Districts.

Summary Objectives An analysis of the risk factors and seasonal and spatial distribution of individuals with subclinical malaria in hypoendemic Bangladesh was performed. Methods From 2009 to 2012, active malaria surveillance without regard to symptoms was conducted on a random sample ( n =3971) and pregnant women ( n =589) during a cohort malaria study in a population of 24000. Results The overall subclinical Plasmodium falciparum malaria point prevalence was 1.0% ( n =35), but was 3.2% ( n =18) for pregnant women. The estimated incidence was 39.9 per 1000 person-years for the overall population. Unlike symptomatic malaria, with a marked seasonal pattern, subclinical infections did not show a seasonal increase during the rainy season. Sixty-nine percent of those with subclinical P. falciparum infections reported symptoms commonly associated with malaria compared to 18% without infection. Males, pregnant women, jhum cultivators, and those living closer to forests and at higher elevations had a higher prevalence of subclinical infection. Conclusions Hypoendemic subclinical malaria infections were associated with a number of household and demographic factors, similar to symptomatic cases. Unlike clinical symptomatic malaria, which is highly seasonal, these actively detected infections were present year-round, made up the vast majority of infections at any given time, and likely acted as reservoirs for continued transmission.

Agrobacterium -mediated genetic transformation protocol was established for two chickpea ( Cicer arietinum L.) varieties, namely Barichhola-4 (Bch-4) and Barichhola-5 (Bch-5). Transformation ability of different explants such as decapitated embryo with single cotyledon disc (DEC), decapitated embryo (DE) and slice embryo decapitated at shoot end with single cotyledon disc (SEC) were tested using Agrobacterium tumefaciens strain LBA4404 harbouring binary plasmid pBI121, containing the GUS and nptII genes. Maximum transformation ability was exhibited by explants of decapitated embryo (DE) from Barichhola-5 (Bch-5). The optimum regeneration from the transformed tissue was achieved on MS supplemented with 0.5 mg/l BAP, 0.5 mg/l Kn and 0.2 mg/l NAA along with double the amount of CaCl 2 and KNO 3 . Selection of the transformed shoots was carried out by gradually increasing the concentration of kanamycin to 150 mg/l. Stable expression of the GUS gene was detected in various parts of the transformed shoots through GUS histochemical assay. Stable integration of nptII gene within the genomic DNA from these transformed shoots was confirmed through PCR analysis. DOI: http://dx.doi.org/10.3329/ptcb.v22i1.11258 Plant Tissue Cult. & Biotech. 22 (1): 41-50, 2012 (June)

Background. In recent studies, the combination of azithromycin and artesunate has proven to be a promising alternative for the treatment of uncomplicated falciparum malaria. Methods. We conducted a randomized, controlled clinical trial assessing the efficacy of azithromycin-artesunate combination therapy. The study was conducted involving 228 patients aged 8-65 years. Patients were randomized to 1 of 2 cohorts at a ratio of 2:1, receiving either azithromycin-artesunate once daily for 3 days (30 mg/kg per day of azithromycin plus 4 mg/kg per day of artesunate) or an adult dose of 80 mg of artemether plus 960 mg of lumefantrine (4 tablets Coartem or the equivalent for children weighing

The research work was undertaken for detection and determination of antibiogram profile of Escherichia coli (E. coli ) that produce Shiga toxin from apparently healthy broilers (n=8) from different commercial farms of Jessore, Bangladesh. Broiler cloacal swabs (n=8) were collected by inserting the sterile swab stick in the cloacae of broiler and inoculated into peptone water for enrichment for 24 hours at 37°C. Enriched culture was streaked onto Eosin Methylene Blue (EMB) agar for isolation of pure bacterial culture. Then pure bacterial culture was streaked onto Mac-Conkey (MC) agar to identify Gram negative bacteria. Cultural method, Gram staining, biochemical reaction and polymerase chain reaction technique were used to identify the bacteria. The antibiogram profiles of bacteria were investigated against 6 commonly used antibiotics (Ciprofloxacin, Ampicillin, Colistinsulphate, Erythromycin, Neomycin and Penicillin) by disc diffusion method. Five E. coli isolates were identified and Shiga toxin producing E. coli (STEC) was detected by amplifying 372-bp fragment of Stx2 gene in polymerase chain reaction (PCR) assay. The prevalence of the Shiga toxin generating E. coli (STEC) in broiler cloacal swab was 62.5%. All isolates (100%) were resistant to Ampicillin, Colistinsulphate, Erythromycin, Neomycin and Penicillin and sensitive to Ciprofloxacin. The findings of this research strongly imply that broiler harbor multidrug resistant and Shiga toxin producing E. coli (STEC) which may cause public health problem if enter into human food chain.

Cryptosporidium species are a common cause of diarrhea, which can be severe and protracted in young children and immunocompromised individuals.A cohort of 226 Bangladeshi children aged 2-5 years was prospectively followed for3 years to study the role of host genetics in susceptibility to infection, as well as the community impact of cryptosporidiosis on this population.Ninety-six children (42.5%) received a diagnosis of Cryptosporidium infection. A total of 51 (22.6%) had asymptomatic infection. Fifty-eight (25.7%) had cryptosporidiosis, of whom 17 (29.3%) had recurrent disease. Children with cryptosporidiosis presented early, and most had abdominal pain and a short course of diarrhea. Infected children were more likely to carry the human leukocyte antigen (HLA) class II DQB1*0301 allele, particularly those with both asymptomatic and symptomatic infection (P = .009); a strong association was found between carriage of the DQB1*0301/DRB1*1101 haplotype and development of both asymptomatic and symptomatic infection (P = .009). Infected children were also more likely to carry the B*15 HLA class I allele.This is the first study to describe a possible genetic component of the immune response to Cryptosporidium infection, which includes HLA class I and II alleles. Cryptosporidiosis in Bangladeshi children aged 2-5 year is common and often recurrent, but the duration is shorter and the abdominal pain greater than that described in children aged2 years.

Shiga toxin genes (stx) harbouring Escherichia coli (STEC) strains were isolated and identified from diarrhoeal patients visiting the Dhaka Hospital of ICDDR,B: Centre for Health and Population Research, Dhaka, Bangladesh. Of the 189 E. coli strains isolated from 775 diarrhoeal stool specimens, 19 harboured stx1, and one isolate was revealed to have amplicons for both stx1 and stx2 by a PCR assay. Sequence analysis of the 349-bp stx1 from representative isolates revealed 100% homology with the sequence of stx1 available in the GenBank. Among the stx1 positive isolates, two harboured the eae but none were positive for hlyA, katP, etpD or saa genes. Fifteen of the 20 stx positive strains could be categorized into 13 non-O157 serogroups while 4 were untypable and one was a rough strain. Most of the STEC strains were resistant to ampicillin, cephalothin, co-trimoxazole, tetracycline, and nalidixic acid. In the Vero cell assay, all the strains were negative for expression of Shiga toxin (Stx). Randomly amplified polymorphic DNA (RAPD) PCR analysis demonstrated genetic diversity. This is one of the first reports to show the presence of STEC in diarrhoeal patients in Bangladesh.

Humoral immunity develops in the spleen during blood-stage Plasmodium infection. This elicits parasite-specific IgM and IgG, which control parasites and protect against malaria. Studies in mice have elucidated cells and molecules driving humoral immunity to Plasmodium, including CD4(+) T cells, B cells, interleukin (IL)-21 and ICOS. IL-6, a cytokine readily detected in Plasmodium-infected mice and humans, is recognized in other systems as a driver of humoral immunity. Here, we examined the effect of infection-induced IL-6 on humoral immunity to Plasmodium. Using P.chabaudi chabaudi AS (PcAS) infection of wild-type and IL-6(-/-) mice, we found that IL-6 helped to control parasites during primary infection. IL-6 promoted early production of parasite-specific IgM but not IgG. Notably, splenic CD138(+) plasmablast development was more dependent on IL-6 than germinal centre (GC) B-cell differentiation. IL-6 also promoted ICOS expression by CD4(+) T cells, as well as their localization close to splenic B cells, but wasnot required for early Tfh-cell development. Finally, IL-6 promoted parasite control, IgM and IgG production, GC B-cell development and ICOS expression by Tfh cells in a second model, Py17XNL infection. IL-6 promotes CD4(+) T-cell activation and B-cell responses during blood-stage Plasmodium infection, which encourages parasite-specific antibody production.

Background Pregnancy is a known risk factor for malaria which is associated with increased maternal and infant mortality and morbidity in areas of moderate-high malaria transmission intensity where Plasmodium falciparum predominates. The nature and impact of malaria, however, is not well understood in pregnant women residing in areas of low, unstable malaria transmission where P. falciparum and P. vivax co-exist. Methods A large longitudinal active surveillance study of malaria was conducted in the Chittagong Hill Districts of Bangladesh. Over 32 months in 2010–2013, the period prevalence of asymptomatic P. falciparum infections was assessed by rapid diagnostic test and blood smear and compared among men, non-pregnant women and pregnant women. A subset of samples was tested for infection by PCR. Hemoglobin was assessed. Independent risk factors for malaria infection were determined using a multivariate logistic regression model. Results Total of 34 asymptomatic P. falciparum infections were detected by RDT/smear from 3,110 tests. The period prevalence of asymptomatic P. falciparum infection in pregnant women was 2.3%, compared to 0.5% in non-pregnant women and 0.9% in men. All RDT/smear positive samples that were tested by PCR were PCR-positive, and PCR detected additional 35 infections that were RDT/smear negative. In a multivariate logistic regression analysis, pregnant women had 5.4-fold higher odds of infection as compared to non-pregnant women. Malaria-positive pregnant women, though asymptomatic, had statistically lower hemoglobin than those without malaria or pregnancy. Asymptomatic malaria was found to be evenly distributed across space and time, in contrast to symptomatic infections which tend to cluster. Conclusion Pregnancy is a risk factor for asymptomatic P. falciparum infection in the Chittagong Hill Districts of Bangladesh, and pregnancy and malaria interact to heighten the effect of each on hemoglobin. The even distribution of asymptomatic malaria, without temporal and spatial clustering, may have critical implications for malaria elimination strategies.

The reaction of [Os3(CO)10(μ-dppm)] (1) with 1-vinylimidazole at 110°C afforded two novel trosmium compounds, [(μ -H)Os 3 (CO) 7 (μ-2,3-η 2 - C=NCH=CHN CH=CH 2 ) (η 1 - CH=NCH=CHN –CH=CH2){μ3-η3-PPhCH2PPh(C6H4)}] (3) and [Os3(CO)8(μ-2,3-η2- C=NCH=CHN CH=CH 2 )(η1- CH=NCH=CHN CH=CH 2 )(μ3-η2-PPhCH2PPh2)] (4). The compounds have been characterized by elemental analysis, IR, 1H and 31P{1H} NMR and mass spectrometry together with an X-ray analysis for 3, which has a unique structure with a bridging hydride, an N-coordinated η1-vinylimidazole, a dimetallated μ-η2-vinylimidazolide and a μ3-η3-PPhCH2PPh(C6H4) ligands.

Background In the past many regions of Bangladesh were hyperendemic for malaria. Malaria control in the 1960s to 1970s eliminated malaria from the plains but in the Chittagong Hill Tracts remained a difficult to control reservoir. The Chittagong Hill Tracts have areas with between 1 and 10% annual malaria rates, predominately 90-95% Plasmodium falciparum. In Southeast Asia, multiplicity of infection for hypo-endemic regions has been approximately 1.5. Few studies on the genetic diversity of P. falciparum have been performed in Bangladesh. Anderson et al. performed a study in Khagrachari, northern Chittagong Hill Tracts in 2002 on 203 patients and found that parasites had a multiplicity of infection of 1.3 by MSP-1, MSP-2 and GLURP genotyping. A total of 94% of the isolates had the K76T Pfcrt chloroquine resistant genotype, and 70% showed the N86Y Pfmdr1 genotype. Antifolate drug resistant genotypes were high with 99% and 73% of parasites having two or more mutations at the dhfr or dhps loci. Methods Nested and real-time polymerase chain reaction (PCR) methods were used to genotype P. falciparum using antigenic polymorphic markers and to study anti-malarial drug resistance markers in malaria endemic areas of Bangladesh. Results The analysis of polymorphic and drug resistant genotype on 33 paired recrudescent infections after drug treatment in the period 2004 to 2008 in the Chittagong Hill Tracts, which is just prior to countrywide provision of artemisinin combination therapy. Overall the multiplicity of infection for MSP-1 was 2.7 with a slightly smaller parasite diversity post-treatment. The 13 monoclonal infections by both GLURP and MSP-1 were evenly divided between pre- and post-treatment. The MSP-1 MAD block was most frequent in 66 of the samples. The prevalence of the K76T PfCRT chloroquine resistant allele was approximately 82% of the samples, while the resistant Pfmdr1 N86Y was present in 33% of the samples. Interestingly, the post-treatment samples had a small but significantly higher frequency of the sensitive PfCRT alleles by RT-PCR. Conclusion The parasite population retains high population diversity despite hypo-endemic transmission with retention, but decrease in the chloroquine-resistant allele and Pfmdr1 resistant alleles in the Chittagong Hill Tracts of Bangladesh.

A recent active cross sectional survey by a rapid diagnostic test (RDT) in 2007 showed crude malaria prevalence is 11% among the 1.5 million people most at risk for malaria in Bangladesh. An active randomized population malaria surveillance was initiated by JHMRI and ICDDR,B in Kuhalong union near hypoendemic Bandabarn in the Chittagong hill tracts of Bangladesh. The population of Kuhalong is 11,000 with approximately 2,000 households which were enumerated in a baseline census with a GIS mapping component. A demographic surveillance system and knowledge attitude and practice surveys have been obtained as part of the project to follow mosquito vectors by monthly trapping, host susceptibility factors and malariometrics. Here we present results from weekly malariometrics during the October to March low transmission season in the age groups of less than 5, 5 to 15 and greater than 15 years. Microscopy, RDT and real-time PCR was performed on active surveillance showing approximately 2% positive rates by microscopy or RDT in close to 500 individuals. A real-time PCR assay detected 6% prevalence. The sensitivity of the RT-PCR in the 96-well format was increased to 10-100 parasites per microliter with a glycogen/ acetate DNA precipitation at low speed tabletop centrifugation after column extraction. We detected P. vivax and P. malariae in less than 5% of the malaria positive patient samples by RT-PCR. All the P. falciparum isolates were chloroquine resistant PfCRT K76T genotype and atovaquone sensitive PfCYTb 268Y by fluorescent TAQman probe analysis. A reverse transcriptase real-time PCR assay from dried blood on filter papers was able to detect gametocytes. Studies on malaria seropositivity rates are in progress. In summary, a significant asymptomatic malaria PCR positive population exists. The role of this subpopulation in contributing to continuing transmission is being evaluated. Chloroquine resistance is fixed in this geographic area still responsive to artemisinin combination therapy.

Bangladesh faces increasing levels of chloroquine resistance, and drug sensitivity to sulfadoxine-pyremethamine is already compromised. Therefore, the Ministry of Health recently changed the national treatment guidelines to artemisinin-based combination therapies. The purpose of this study was to determine the baseline therapeutic efficacy of artemether-lumefantrine used as a six-dose regimen for the treatment of uncomplicated Plasmodium falciparum malaria. Sixty-seven patients were enrolled in the study; the cure rate in a 42-day follow-up after an adjustment by polymerase chain reaction was 94.3%. The treatment led to rapid fever (mean +/- SD = 25.82 +/- 12.14 hours) and parasite (30.36 +/- 19.43 hours) clearance. These data suggest that artemether-lumefantrine is a highly efficacious and well-tolerated treatment for uncomplicated P. falciparum malaria in Bangladesh.

BackgroundMalaria is endemic in 13 of 64 districts of Bangladesh, representing a population at risk of about 27 million people. The highest rates of malaria in Bangladesh occur in the Chittagong Hill Districts, and Plasmodium falciparum (predominately chloroquine resistant) is the most prevalent species.MethodsThe objective of this research was to describe the epidemiology of symptomatic P. falciparum malaria in an area of Bangladesh following the introduction of a national malaria control program. We carried out surveillance for symptomatic malaria due to P. falciparum in two demographically defined unions of the Chittagong Hill Districts in Bangladesh, bordering western Myanmar, between October 2009 and May 2012. The association between sociodemographics and temporal and climate factors with symptomatic P. falciparum infection over two years of surveillance data was assessed. Risk factors for infection were determined using a multivariate regression model.Results472 cases of symptomatic P. falciparum malaria cases were identified among 23,372 residents during the study period. Greater than 85% of cases occurred during the rainy season from May to October, and cases were highly clustered geographically within these two unions with more than 80% of infections occurring in areas that contain approximately one-third of the total population. Risk factors statistically associated with infection in a multivariate logistic regression model were living in the areas of high incidence, young age, and having an occupation including jhum cultivation and/or daily labor. Use of long lasting insecticide-treated bed nets was high (89.3%), but its use was not associated with decreased incidence of infection.ConclusionHere we show that P. falciparum malaria continues to be hypoendemic in the Chittagong Hill Districts of Bangladesh, is highly seasonal, and is much more common in certain geographically limited hot spots and among certain occupations.

Background Until recently the Chittagong Hill tracts have been hyperendemic for malaria. A past cross-sectional RDT based survey in 2007 recorded rates of approximately 15%. This study was designed to understand the present epidemiology of malaria in this region, to monitor and facilitate the uptake of malaria intervention activities of the national malaria programme and to serve as an area for developing new and innovative control strategies for malaria. Methods This research field area was established in two rural unions of Bandarban District of Bangladesh north of Bandarban city, which are known to be endemic for malaria due to Plasmodium falciparum. The project included the following elements: a) a demographic surveillance system including an initial census with updates every four months, b) periodic surveys of knowledge attitude and practice, c) a geographic information system, d) weekly active and continuous passive surveillance for malaria infections using smears, rapid tests and PCR, f) monthly mosquito surveillance, and e) daily weather measures. The programme included both traditional and molecular methods for detecting malaria as well as lab methods for speciating mosquitoes and detecting mosquitoes infected with sporozoites. Results The demographic surveillance enumerated and mapped 20,563 people, 75% of which were tribal non-Bengali. The monthly mosquito surveys identified 22 Anopheles species, eight of which were positive by circumsporozoite ELISA. The annual rate of malaria was close to 1% with 85% of cases in the rainy months of May-October. Definitive clustering identified in the low transmission season persisted during the high transmission season. Conclusion This demographically and geographically defined area, near to the Myanmar border, which is also hypoendemic for malaria, will be useful for future studies of the epidemiology of malaria and for evaluation of strategies for malaria control including new drugs and vaccines.